NYSDEC LAKE ERIE 2008 ANNUAL REPORT

Transcription

1 New York State Department of Environmental Conservation Division of Fish, Wildlife and Marine Resources NYSDEC LAKE ERIE 28 ANNUAL REPORT to the Lake Erie Committee and the Great Lakes Fishery Commission Lake Erie Eastern Basin New York March 29 New York State Department of Environmental Conservation 625 Broadway, Albany, New York David A. Paterson, Governor

2 STUDIES REPORTED IN THIS DOCUMENT ARE SUPPORTED BY THE FEDERAL AID IN SPORT FISH RESTORATION PROGRAM

3 NYS DEC LAKE ERIE 28 ANNUAL REPORT to the Lake Erie Committee Report Section Authors: Donald W. Einhouse Supervising Aquatic Biologist - NYS DEC Lake Erie Unit James L. Markham Senior Aquatic Biologist - NYS DEC Lake Erie Unit Kevin A. Kapuscinski Research Assistant - SUNY ESF at Syracuse Michael L. Wilkinson Senior Aquatic Biologist - NYS DEC Region 9 Fisheries Michael T. Todd Aquatic Biologist - NYS DEC Region 9 Fisheries Lake Erie Unit Technical Support: Douglas L. Zeller Research Vessel Captain - Lake Erie Unit Richard C. Zimar Senior Fish & Wildlife Technician - Lake Erie Unit Brian J. Beckwith Senior Fish & Wildlife Technician - Lake Erie Unit Clerical Assistance: Mari Ellen ( Ginger ) Szwejbka Secretary 1 - Lake Erie Unit Acknowledgments Great Lakes program supervision is adeptly provided by William Culligan. The Lake Erie Fisheries Unit also recognizes the contributions of seasonal staff that are essential to completing an ambitious field program. During 28 field year these individuals included Fish and Wildlife Technician s Mark Dusablon, Carrie Babcock, Pete Krakowiak, and Paul Andrews. We also acknowledge contributions of DEC s Chautauqua Fish Cultural Station, DEC s Region 9 Fisheries Office, SUNY Fredonia s Biology Department and Buffalo State College s Great Lakes Center in supporting various Lake Erie field activities.

4 TABLE OF CONTENTS New York State Department of Environmental Conservation Lake Erie Unit Dunkirk, New York 1448 Presented at the Lake Erie Committee Meeting Ypsilanti, Michigan March 23, 29 SECTION TITLE A B C D E F G H I J K L M N EXECUTIVE SUMMARY RESEARCH PARTNERSHIPS (D. W. Einhouse and J. L. Markham) JUVENILE YELLOW PERCH TRAWL SURVEY (D. W. Einhouse) WARMWATER GILL NET ASSESSMENT (D. W. Einhouse) WALLEYE TAGGING STUDY (D. W. Einhouse) COLDWATER ASSESSMENT SURVEY (J. L. Markham) SEA LAMPREY ASSESSMENT (J. L. Markham) 28 SALMONINE STOCKING SUMMARY (J. L. Markham and M. A. Wilkinson) THE 27 LAKE ERIE SALMONID ANGLER DIARY PROGRAM (J. L. Markham) WILD STEELHEAD ASSESSMENT PROGRAM (J. L. Markham) FISHERIES ACOUSTIC SURVEY (D. W. Einhouse and L. Witzel) WALLEYE DIET STUDY (D. W. Einhouse) FORAGE TRAWL SURVEY (D. W. Einhouse) OPEN LAKE SPORT FISHING SURVEY (D. W. Einhouse) O BUFFALO RIVER WALLEYE REHABILITATION (D. W. Einhouse and M. A. Wilkinson) P Q R COMMERCIAL FISHERY ASSESSMENT (D. W. Einhouse) PUBLIC INFORMATION AND EXTENSION (M. T. Todd) SAMPLING EFFORTS FOR YOUNG-OF-YEAR (26-28) AND ADULT MUSKELLUNGE (28) IN THE BUFFALO HARBOR, LAKE ERIE, AND THE UPPER NIAGARA RIVER (K. L. Kapuscinski, M. A. Wilkinson, and J. M. Farrell)

5 New York State Department of ENVIRONMENTAL CONSERVATION New York s 28 Lake Erie Fisheries Program Highlights The New York State Department of Environmental Conservation s Lake Erie Fisheries Unit is responsible for fishery research and assessment activities for one of New York s largest and most diverse freshwater fishery resources. A variety of annual programs are intended to achieve an improved understanding of Lake Erie s fish community to guide fisheries management, and safeguard this valuable resource for current and future generations. This document shares just a few of the highlights from the 28 program year. A much more complete annual report is available on DEC s website at or by contacting DEC s Lake Erie Unit office, the contact information provided at the bottom of this page. Walleye Lake Erie s eastern walleye resource is composed of locally spawning stocks, as well as contributions from summertime movements from western basin spawning stocks. The annual movement of western basin stocks is now well known via longterm tagging studies conducted throughout the lake. Walleye fishing quality in recent years has been excellent and largely attributable to excellent spawning success observed in 23. However, despite excellent fishing quality, walleye fishing activity, as well as overall boat activity are experiencing long-term declines from factors not apparently linked to fishing quality. Our most recent juvenile walleye surveys indicate average spawning success also occurred from 25 to 27, suggesting the adult population will somewhat decline from a peak a few years earlier. Catch per Net Age-1 Walleye Index 1984 year class 23 year class Year Class Smallmouth Bass Lake Erie supports New York s and perhaps the country s finest smallmouth bass fishery. Generally stable annual spawning success, coupled with excellent survival to old ages, produces high angler catch rates and frequent encounters with trophy-sized fish. Our bass monitoring program finds the current bass population slightly above long-term abundance levels, and particularly high catches of juvenile bass in recent years forecast abundance of the adult population to remain high in the near future. Catch per Net Smallmouth Bass Index 5 45 age age 3 to 7 35 age 1 & Yellow Perch The yellow perch resource in eastern Lake Erie has experienced wide oscillations in abundance over the last 3 years, reaching a low ebb in the mid-199 s, and since then experiencing an extended recovery that began about 21. A large adult population continues to produce good catch rates for anglers especially during spring and fall seasons, with an average harvested size of 1.5 inches. Measures of juvenile yellow perch abundance each of the last three years have also been especially high, suggesting the recent large and more stable adult abundance will extend at least another few years. Gill Net Catches of Yellow Perch Catch per Net age 7 + age 3 to 6 age 1 & Lake Erie Fisheries Unit 178 Point Drive North Dunkirk, NY (716)

6 Lake Trout Rehabilitation of a self-sustaining lake trout population in the eastern basin of Lake Erie continues to be a major thrust in New York s Great Lakes coldwater fisheries management program. Lake trout have been stocked annually since 1978 and assessment programs monitor the status of progress. A revised lake trout rehabilitation plan was completed in 28 and will guide future recovery efforts. Abundance of lake trout in the New York waters of Lake Erie has been slowly increasing since 2 and has reached the levels found in the 199s, but lakewide abundance remains well below targets. Over 95% of the current population is comprised of young fish between 2 and 5 years old. Additional stocking and continued sea lamprey control is needed in order to build adult lake trout populations to levels were natural production is a possibility. Catch per Net Gill Net Catches of Lake Trout Age 1 to 4 Age 5 & 6 Age Steelhead and Salmonid Stocking New York annually stocks around 27, steelhead and 35, brown trout into Lake Erie and its tributaries to provide recreational opportunities for both lake and stream anglers. Tributary angling for steelhead, assessed through an angler diary program, continues to show the excellent fishery that has developed with average catch rates exceeding.5 fish/hour. Wild reproduction of steelhead also occurs that contributes to the fishery as well. Juvenile assessment programs conducted since 21 confirmed substantial numbers of young-of-year steelhead present in the fall on many tributaries. Pre-passage monitoring is occurring on Chautauqua Creek in anticipation of a fish passage project that will hopefully improve natural reproduction in this stream. Fishing quality is expected to remain good in the near future. Sea Lamprey Sea lamprey invaded Lake Erie and the Upper Great Lakes in the 192s and have played an integral part of the failure of many native coldwater fish stocks. Sea lamprey control in Lake Erie began in 1986 in support of lake trout rehabilitation efforts, and regular treatments are conducted to control lamprey populations. Annual monitoring consists of observations of sea lamprey wounds on lake trout and nest counts on standard stream sections. Both wounding rates and nest counts declined 6% in 28 compared to 27, indicating that the Lake Erie sea lamprey population is declining due to recent control measures. Back-toback lampricide treatments of all key Lake Erie tributaries began in 28 and will continue in 29, and these treatments are expected to reduce sea lamprey wounding to below target levels by 21. Wounds per 1 Fish Sea Lamprey Wounding Rate on Lake Trout >21 inches Target = 5 wounds/1 fish Prey Fish The Lake Erie Unit also participates in a number of investigations to assess forage fishes and other components of the lake ecosystem. These investigations include trawl, sonar, surveys of prey fishes, and predator diet studies. A variety of prey fish investigations beginning approximately 15 years ago found rainbow smelt as the dominant component of the open lake forage fish community. However in recent years there has been a notable shift to increased prey species diversity, somewhat lower smelt abundance, and an especially high incidence of round gobies and emerald shiners found in both prey fish collections and predator diets. Over time we expect investigations to be useful in furthering our understanding of factors shaping the fish community. Number (thousands) Trout & Salmon Stocking in NY Lake Trout Coho Chinook Brown trout 6 Dom. Rainbow trout Steelhead Catch per Hectare Trawl Catches of Prey Fish clupeids soft-rayed spiny-rayed 8, 6, 4, 2, Lake Erie Fisheries Unit 178 Point Drive North Dunkirk, NY (716)

7 NYSDEC Lake Erie Annual Report 28 B. RESEARCH PARTNERSHIPS The Lake Erie Unit collaborates with investigators from other government and academic institutions to pursue a broad array of initiatives (Table S.1). The Lake Erie Unit s contribution to these partnerships usually includes vessel and staff time for field collections, and/or sharing archived data series spanning many years of standard sampling programs. The Lake Erie Unit remains amenable to pursuing additional partnerships to the extent such projects remain consistent with our mission, and practical for integrating any new effort with our ongoing programs. Table B list of active research partnerships with NYS DEC Lake Erie Unit. Principal Investigator Geddes et al. Johnson, T. Keir, M. Lantry, B. Kocovsky et al. Mackey, S. McIntyre, P. Murphy, E. Noyes et al. Rudstam et al. Rutherford et al. Stepien et al. Strakosh et al. Strakosh et al. Strakosh et al. Strakosh et al. Strakosh et al. Vandergoot et al. Wang, H. et al. Zhao et al. Project Name The Lake Erie GIS data base Comparison of whitefish from Lakes Erie, Michigan, and Superior Contaminant testing of Lake Erie lake trout Energetics of juvenile lake trout across the Great Lakes Yellow perch morphology in Lake Erie Identification and mapping of lake trout spawning areas in Lake Erie Genetic analysis of Great Lakes white sucker population structure US EPA GLNPO Great Lakes Fish Monitoring Program Surveillance for VHS virus in New York State Great Lakes Acoustic Standard Operating Procedures Spatial analysis of yellow perch fisheries and populations in Lake Erie Genetic Stock Structure of Lake Erie Yellow Perch Spawning Groups Smallmouth bass genetic analysis in New York s portion of Lake Erie Movement patterns of potadromous Smallmouth bass in Lake Erie Effects of dam passage on the fish community of Chautauqua Creek Economic benefits of the Lake Erie steelhead fishery to western New York Walleye year class formation in New York s portion of Lake Erie The Lake Erie Walleye PIT Tag Study Inter-stock variation of maturation schedules of walleye in the Great Lakes Development of an east basin Lake Erie walleye stock assessment model Section B Page 1

8 NYSDEC Lake Erie Annual Report 28 C. JUVENILE YELLOW PERCH TRAWL SURVEY Donald W. Einhouse Introduction The Lake Erie Unit s long-term bottom trawling program has the principal objectives of assessing trends in abundance of juvenile yellow perch, and monitoring the status of the forage fish community. Results from this program are also merged with broader lake wide assessments of yellow perch and forage fish populations and reported with the interagency Forage Task Group (FTG 28) and Yellow Perch Task Group Reports (YPTG 28). Aspects of this program that specifically describe forage status are described in more detail in Section M. Methods This fall trawling series was initiated in 1992 and replaced the Juvenile Percid Assessment conducted from 1986 to 1991 (Culligan et al. 1992). The current trawling program is conducted during October at randomly selected stations between the 5- and 1-ft depth contours in New York s portion of Lake Erie. Standard tow duration is 1 minutes. Survey procedures generally follow those performed for an inter-agency, western basin Lake Erie assessment that is reported annually in Lake Erie s Forage Task Group Report (FTG 28). The standard gear for this trawling program is a 4- seam bottom trawl with the following characteristics: Headrope length: Footrope length: Ground wire to doors: Trawl webbing: Twine diameter: Cod-end webbing: 31.8 ft 38.1 ft 6.4 ft 2. inches 21 thread.4 inches included 34 usable tows, totaling 34 minutes (5.7 hours). This effort was distributed among stations ranging in depths between 5 ft to 1 ft. Seven sample days, from October 7 to 23, completed the 28 assessment. Reported measures conform to a lakewide standard of reporting trawl densities as mean number per hectare (FTG 1998). A hectare is acres. The area density is computed from known trawl fishing dimensions measured from previous calibrations and individual tow distances estimated from navigation equipment. Beginning in 24 NYS DEC secured equipment to measure the fishing dimensions of each trawl sample collected for this program. Our new monitoring capability suggests the currently measured trawl wing spread is significantly wider than previously indicated by standard fishing dimensions assigned from a late-199's trawl measurement exercise. Nevertheless, for the analyses in this report we continued to apply the previous standard fishing dimensions to remain consistent with long term procedures. A separate investigation by the Forage Task Group is reviewing New York s trawl measurement data to determine whether such equipment should become part of the standard operating procedures for trawl programs on Lake Erie conducted by other jurisdictions. Results Summary statistics for trawl catches of 14 frequently encountered species are presented in Table C.1. In 28, the most abundant species encountered in this program was rainbow smelt. Other species that made large contributions to the trawl collections included yellow perch, trout-perch and white perch. Overall standard daytime trawling effort in 28 Section C Page 1

9 NYSDEC Lake Erie Annual Report 28 TABLE C.1 CPE (number per hectare) of selected species collected with a 1-m bottom trawl from approximately 3 sites between 5 to 1 ft depth contours in New York waters of Lake Erie, October, Species Yellow Perch Age Age 1 Age 2+ Index (#/ha) (1992 to 27) Min Max Mean Trawl (#/ha) 28 1, Walleye Age White Perch Age White Bass Age Rainbow Smelt Age Age ,154. 2, , , Alewife Age Gizzard Shad Age Trout-Perch All ages 27. 1, Sm. Bass Age Age 1+ Emerald Shiner Age Age 1+ Spottail Shiner Age Age 1+ Round Goby Age Age 1+ Burbot Age Age , Whitefish Age # of Samples A more detailed description of abundance measures for forage fish species encountered in this trawling program are described in Section M of this report. The 28 mean density estimates for age-, age-1 and adult (age-2 and older) yellow perch were all higher than the previous 16-year mean density estimates for each of these life stages of yellow perch. The 28 young-of-the-year (YOY) yellow perch index was the highest measure observed in the entire trawl series by a wide margin. The 28 index for age-1 yellow perch was also notable as the highest age-1 yellow perch measure in this trawl series, by only slightly surpassing the previous high in observed in 27. Very high age-1 yellow perch abundance has now been estimated for three consecutive years, and four of the last five years. Trends in juvenile yellow perch growth rates are presented in Figure C.1. Both age- and age-1 yellow perch mean total length values in 28 are near the largest values of this data series. total length (inches) age- Juvenile Yellow Perch Growth age Figure C.1. Mean total length of age- and age-1 yellow perch collected by bottom trawl in New York waters of Lake Erie, October Error Bars are 95 % confidence intervals. During 1997 only one age- yellow perch was collected and error bars could not be computed. Discussion This October trawling program continues to portray an improved status of the yellow perch population relative to a long period of low abundance through the 199's. These results also closely mirror findings from other Lake Erie jurisdictions and support the view that yellow perch abundance has rebounded and stabilized relative to the 199's low ebb. Especially high age-1 yellow perch indices in three consecutive years from 26 through 28 suggest favorable abundance of adult yellow perch (age-2+) will continue for the near future. A broader, basin-wide summary, describing yellow perch population trends is provided in the annual report of the Yellow Perch Task Group (YPTG 28). Section C Page 2

10 NYSDEC Lake Erie Annual Report 28 References Culligan, W. J., F. C. Cornelius, D. W. Einhouse, D. L. Zeller, and R. C. Zimar Annual Report to the Lake Erie Committee. New York Department of Environmental Conservation, Albany. 52 pp. FTG Report of the Lake Erie Forage Task Group. Presented to the Standing Technical Committee, Lake Erie Committee, Great Lakes Fishery Commission Annual Meeting of the Lake Erie Committee. FTG 28. Report of the Lake Erie Forage Task Group. Presented to the Standing Technical Committee, Lake Erie Committee, Great Lakes Fishery Commission. YPTG 28. Report of the Lake Erie Yellow Perch Task Group. Presented to the Standing Technical Committee, Lake Erie Committee, and Great Lakes Fishery Commission. Section C Page 3

11 NYSDEC Lake Erie Annual Report 28 D. WARMWATER GILL NET ASSESSMENT Donald W. Einhouse Introduction An annual gill net assessment of the warm water fish community represents the oldest, standard survey performed by New York s Lake Erie Fisheries Unit and 28 marked the 28 th year of this ongoing effort. The principal objective of this September gill net survey is to produce measures of abundance, age composition and growth of walleye, smallmouth bass and yellow perch in New York s portion of Lake Erie. Walleye and yellow perch measures of abundance and age composition are also contributed to the inter-agency Walleye and Yellow Perch Task Groups for broader lake wide assessment of the walleye and yellow perch populations. A secondary objective for this gill net assessment is to monitor trends in abundance for other commonly encountered warmwater fish species. Methods This annual, autumn gill netting survey has been underway since However, methods for conducting this program were significantly altered after 1992 to accommodate adoption of an interagency approach to assessment of the fish community. A detailed description of the current procedures can be found in the report of the Lake Erie Committee s Index Fishing Work Group (Ryan et al. 1993). As part of these current procedures, several fixed sampling stations from New York s former (< 1993) gill netting program on Lake Erie were retained to maintain continuity of a long-term data series for especially shallow (<39 ft) waters. Long-term catch rates presented in this report focus principally on the inshore (<5 ft) stratum, where a standard sampling strategy has been performed since The current, overall sampling strategy for this program is a stratified, random approach with stations selected from a grid system. Both bottom and limnetic warmwater habitats were sampled with 7-ft monofilament gill nets from 1993 through Beginning in 1996, only bottom habitat has been sampled. Fourteen individual gill net panels were 5 ft by 6 ft and consisted of stretch mesh sizes, ranging from 1.25 to 6. inches for a particular net. One change implemented in 25 was the deletion of the 6. inch mesh panel from New York s standard gill net. An examination of gill net catches from 1993 to 24 found the 6-inch panel contributed miniscule catches for all commonly encountered species, but was otherwise responsible for excessive net damage. The excessive net damage was because our interagency standard monofilament twine diameter is too weak to retain species large enough to be entangled in 6-inch stretch mesh. Beginning in 25 the new configuration for a standard gill net became a 65-ft net consisting of 13 panels ranging from 1.25 to 5.5 inches for a particular net. Previous summary statistics were not re-analyzed with the deletion of 6.-inch panel catches because separate evaluations confirmed the presence/absence of the 6. inch panel did not measurably change overall data series catch rates. The sampling period extends from September 1 to fall turnover. Four to six nets are fished each sample day, and 4 samples were collected in 28. These nets are set between 12: PM and sunset and retrieved between sunrise and 12: noon the following day. Data from gill nets that sampled for more than 24 hours or nets that are badly damaged, tangled, or fouled by debris are omitted from data analyses used to index abundance. Catches from overnight sets are completely Section D Page 1

12 NYSDEC Lake Erie Annual Report 28 enumerated by species. Walleye, yellow perch, and smallmouth bass are examined in greater detail. These species are measured, weighed, sexed, and scales, spines or otoliths are taken for age determination. Large catches of walleye, smallmouth bass and especially yellow perch are sub-sampled as needed to process samples in a timely manner. Results The overall abundance index for walleye at inshore gill net stations in 28 was slightly below the longterm average abundance since 1981 (Table D.1) Table D.1. Catch rates of selected warmwater species per variable mesh gill net from inshore stations (<5 ft) in New York waters of Lake Erie, September-October, SPECIES Gill Net Index ( ) Min. Max. Mean Gill Net Index in 28 Mean 95% Conf. Limit Walleye Smallmouth Bass number per net Walleye: NY Gill Net Index ( - 5 ft) age 8 + age 3 to 7 age 1 & 2 Figure D.2. Walleye catch rates by age category per gill net set from inshore stations (< 5 ft) in New York waters of Lake Erie, September-October, This gill net assessment has had a juvenile walleye emphasis since its inception, with age-1 and age-2 walleye typically comprising a large fraction of the overall walleye sample each year (Figure D.2). Rock Bass White Perch Gizzard Shad Redhorse Sucker walleye age distribution index gill net White Sucker nearshore (< 15 m) offshore (> 15 m ) White Bass Freshwater Drum Channel Catfish Stonecat Quillback Carp catch per net Yellow Perch Alewife age The age composition of this walleye sample was composed mostly of age-1, age-2, and age-5 individuals representing the 27, 26, and 23 year classes, respectively. Adult cohorts older than age-5 were scarcely detected in 28 samples. The age composition of this walleye sample spanning 28 years is shown in Figure D.1. Walleye abundance in gill nets has declined in recent years with attrition of a dominant year class that was produced in 23. Figure D.2. Age composition of walleye collected from the New York waters of Lake Erie, September - October, 28. Yearling walleye catch rates in 28 ranked the 27 year class as below the average, but above the median, and the thirteenth largest measured in this 28-year time series. This somewhat less abundant 27 year class also followed two consecutive years of above average yearling walleye abundance (Figure D.3). Section D Page 2

13 NYSDEC Lake Erie Annual Report 28 catch per net-night yearling walleye index of abundance year class Figure D.3 Relative abundance of age-1 walleye collected from the New York waters of Lake Erie, September-October, Length-at-age trends for juvenile walleye are presented in Figure D.4. Age-1 and age-2 walleye were near long term average sizes for this September netting program. Length of age-1 & age-2 walleye Catch Per Net smallmouth age distribution index gill net nearshore (< 15 m) offshore (15-3m) age Figure D.5. Age composition of smallmouth bass collected from the New York waters of Lake Erie, September-October, 28. Overall smallmouth bass abundance in gill nets has remained at generally high levels during the last nine years, with young fish (age-1 & age-2) contributing the greatest share to this annual collection through recent years (Figure D.6). total length (inches) age-1 age Figure D.4. Mean total length of age-1 & age-2 walleye collected form variable mesh gill nets in the New York waters of Lake Erie, September-October, Error bars are 2 standard errors. 28 number per net Smallmouth Bass: NY Gill Net Index ( - 5 ft) age 8 + age 3 to 7 age 1 & Smallmouth bass catch rates in 28 were above average value for this 28-year time series (Table D.1). Mostly sub-adult smallmouth bass (age-1, age-2, and age-3) contributed to this 28 sample which included 15 age groups from age- to age-15 (Figure D.5). Offshore gill net stations encountered fewer sub-adult cohorts of smallmouth bass than the companion near shore gill net stations. Figure D.6. Smallmouth bass catch rates by age category from inshore stations (< 5 ft) in New York waters of Lake Erie, September-October, The long-term recruitment indices for age-2 and age- 3 smallmouth bass rank the 25 year class as above average abundance. Early indications from this same juvenile recruitment index suggest the 26 year class is also somewhat above average abundance as age-2 individuals (Figure D.7). Section D Page 3

14 NYSDEC Lake Erie Annual Report 28 cpe (number/net-night) juvenile smallmouth bass recruitment age-2 age-3 year class Figure D.7. Relative abundance of age-2 and age-3 smallmouth bass collected from the New York waters of Lake Erie, September - October, Age-2 and age-3 smallmouth bass cohorts averaged 11.8 in and 14.1 in total length, respectively. The age-3 measure was the longest observed in the 28- year time series, and the age-2 measure was the 2 nd highest in the series (Figure D.8). Robust sample sizes accompanied this length analysis, with n = 158 for age-2, and n = 312 for age-3 smallmouth bass, respectively. total length (inches) Mean length of age-2 and age-3 bass age 2 age 3 to 5 ft), long-term gill net sites. Age-1, age-2, age-3 and age-5 yellow perch were the most abundant age groups in the 28 collections and individuals greater than age-7 were more scarce. Adult cohorts of yellow perch have contributed measurably to this annual sample each of the last 9 years (Figure D.9). number per net Yellow Perch: NY Gill Net Index (5 to 1 ft) ages 8 + ages 3 to 7 ages 1 and Figure D.9. Yellow perch catch rates by age category per variable mesh gill net set from sampling locations between 5 and 1 ft in New York waters of Lake Erie, September-October, Abundance measures for all fifteen of the most commonly encountered species in this annual gill net sample are reported in Table D.1. Of these fifteen species, only smallmouth bass and yellow perch were encountered at notably higher than average abundance. Most of the other species were encountered at near average abundance, except white sucker and stonecat catch rates have exhibited a declining trend that has now extended many years Discussion Figure D.8. Mean total length of age-2 and age-3 smallmouth bass collected from gill nets in the New York waters of Lake Erie, September-October, Error bars are 95% confidence limits. In the 5 to 1 ft stratum, yellow perch continued to be encountered at high levels of abundance. This deeper 5 to 1 ft stratum has been sampled since the interagency index fishing protocol was fully implemented in New York, starting in Yellow perch are not effectively sampled at the shallower ( Overall walleye abundance in 28 was somewhat below the average for our time series, with age-1 and age-2 cohorts contributing the largest share to this sample. This gill net index occurs in shallow near shore regions that typically encounter more juvenile than adult walleye in most sampling years. The 28 yearling index for walleye was near long term measures of central tendency (between the mean and median values), but lower than age-1 observations of each of the previous two sampling years. Our most Section D Page 4

15 NYSDEC Lake Erie Annual Report 28 recent index characterizes the 27 year class as very typical of the average yearling walleye production measured over the last 28 years. Smallmouth bass abundance in 28 was above the long term average index, with sub-adult cohorts making the largest share of this sample. Standard recruitment measures describe very good recruitment for the 25 (age-3) year class, and early indications suggesting at least average recruitment for the 26 (age-2) year class. A paper by Einhouse et al. (22) related recruitment patterns of smallmouth bass in New York s portion of Lake Erie to mean summer water temperature. This study found warmer than average summer water temperatures corresponded with production of larger smallmouth bass year classes. This bass recruitment and water temperature data series has been updated annually since this 22 publication and has remained in good agreement that summer water temperatures are at least a coarse predictor of smallmouth bass year class strength. As such, warmer than average summer water temperatures the last two years (27 and 28) at least provide some confidence that recruitment should have been good for those 27 and 28 year classes. We will not have direct measures of abundance for these year classes until they recruit to our gill nets as age-2 individuals over the next two sampling years. One of the most conspicuous long term trends from our smallmouth bass data series has been our long term measure of length-at-age for age-2 and age-3 smallmouth bass. This sub-adult smallmouth bass growth data series continues to show significantly elevated growth rates that began when round gobies became an abundant species in eastern Lake Erie. Particularly notable in 28 was the new record mean length for age-3 smallmouth bass at 14.1 inches, surpassing the previous high measure by a wide margin (.5 inches). Gobies have now been abundant for 9 years in eastern Lake Erie, but notably decreased in abundance for the first time in 28 (see Section C), yet smallmouth bass growth rates have continued to increase through recent years. Presently the observed mean length of Lake Erie smallmouth bass after three and four growing seasons, respectively, exceed measures for New York s other fast growing populations by approximately 2 inches (Green et al. 1986). As such, these smallmouth bass growth data would ostensibly make a good candidate for a study of bass bioenergetics and fish community dynamics. The status of the yellow perch population has improved considerably since the 199 s. Independent gill net and bottom trawling programs (see Section C) continue to corroborate observations of neighboring jurisdictions, and all agree that expanded and more stable abundance of yellow perch now occurs in the eastern Lake Erie. Excellent juvenile recruitment in recent years coupled with a conservative harvest strategy by eastern basin jurisdictions (YPTG 28) seems to have fostered the long term recovery of this resource inhabiting the region of Lake Erie s lowest biological productively, the lake s eastern basin. Abundance trends for some other commonly encountered species have recently received closer scrutiny due to extensive fish kills observed especially during 21 and 22. The species composition of those fish kills consisted largely of freshwater drum, and to a lesser extent, a wide variety of generally benthic species, including rock bass, stonecats, and smallmouth bass. Despite these notable fish kills, we have not yet detected population level declines for freshwater drum in our gill net index. During 25 we also observed an extensive summertime mortality of channel catfish but were unable to obtain suitable fresh samples for examination by pathologists. Subsequent gill net indices found channel catfish catches steadily dropped from 24 through 27, following progressive increases in abundance between 1999 and 23. Recently viral hemorrhagic septicemia (VHS) virus has emerged in the Great Lakes as a serious pathogen of fish. In light of these continuing and unpredictable perturbations, long term index netting remains invaluable as a tool to quantify and Section D Page 5

16 NYSDEC Lake Erie Annual Report 28 understand any accompanying impacts on fish communities. References Einhouse, D. W., W. J. Culligan, and J. Prey. 22. Changes in the smallmouth bass fishery of New York s portion of Lake Erie with Initiation of a spring black bass season. American Fisheries Society Symposium 31:63-614, 22. Green, D. M., B. L. Schonhoff, and W. D. Youngs. The New York State Bass Study Use of angler Collected Data to Determine Population Dynamics. New York State Department of Environmental Conservation, Bureau of Fisheries report. April, Ryan, P., S. Orsatti, D. Einhouse, D. Davies, R. Knight, M. Rawson, M. Turner, J. Murphy, and S. Nepszy Interagency Protocol for Index Fishing with Gill Nets in Lake Erie. Report to the Standing Technical Committee and the Great Lakes Fishery Commission. September, YPTG 28. Report of the Lake Erie Yellow Perch Task Group. Presented to the Standing Technical Committee, Lake Erie Committee, and Great Lakes Fishery Commission. Section D Page 6

17 NYSDEC Lake Erie Annual Report 28 E. WALLEYE TAGGING STUDY Donald W. Einhouse Introduction A long-term, annual walleye tagging program has been pursued by the Lake Erie Unit in conjunction with other Lake Erie jurisdictions since 199. Interagency standard procedures have been adopted and tag recovery data are managed through a centralized database. Lake Erie s inter-agency Walleye Task Group has provided coordination for this annual lake wide assessment. This long term, inter-agency study has been instrumental in advancing our understanding of walleye movements, survival, and exploitation rates on Lake Erie. By 28 most of the lake wide walleye tagging effort had been suspended, however New York and other Lake Erie jurisdictions continue to monitor walleye in fisheries and index netting programs for tag-recaptures. Methods Through the 19 years New York has participated in this interagency tagging study, 21,411 walleye have been tagged in New York s portion of Lake Erie spanning a period from 199 to 27. Walleye were collected by boat shocker and trap nets at springtime spawning locations. During most of the years of this study trap nets contributed a larger portion of the annual sample than the boat shocker. Jaw tags were used throughout the study and we largely relied on voluntary tag returns from fishers to assess walleye movements and mortality rates. From 25 to 27 a supplementary PIT (Passive Integrative Responder) tagging component was also conducted to assess jaw tag loss, jaw tag non-reporting, and develop independent measures of walleye mortality and exploitation rates. Results of this PIT tagging investigation are being pursued as a separate effort by a graduate student at Michigan State University and will not be included with this report. Results Since the inception of this tagging study in 199 through 28, 1,827 tag recoveries originating from the New York tagging sites have been reported by anglers and the Ontario commercial fishery. Sixty seven (67) of these jaw tag recaptures occurred during 28. The origin of many of the recaptures reported in 28 differed markedly from the typical pattern. Typically almost all of the recaptures reported in any given year are from anglers; however in returns (24 %) were from a single Ontario commercial fisherman who reported every one of his recaptures as occurring the previous year, in 27. We have otherwise not received a single report from the Ontario commercial fishery in the last five years. This series of walleye tag recovery data has been annually examined using an old computer program that estimates mean survival and recovery rates for tagged populations (Brownie et al. 1978). Data added from our most recent iteration of the tag recovery matrix has now exceeded the capacity of this old computer program, in a large part because our time series now exceeds 15 years. Moreover this computer program has limited ability to accommodate missing years of tag data, and we did not tag walleye in 28 for the first time since the inception of this study. As such, tag-recapture survival and exploitation estimates provided in our 27 annual report (Einhouse et al. 28) are the most current estimates we can easily produce by employing our long term standard analysis methods. The spatial pattern of jaw tag recoveries spanning the entire study period (199 28) for all jurisdictions and eastern and western basin tagged walleye is presented in Figure E.1. Jaw tagged walleye originating from western basin tagging locations show a much broader lake wide distribution of recoveries than eastern basin tagged Section E Page 1

18 NYSDEC Lake Erie Annual Report 28 walleye, which tend to remain within the eastern basin of the lake. Additionally, most of the eastern basin tag returns occurred along the south shore of the basin where most of the tagging has also occurred through the entire study. A B Figure E.1. The distribution of tag recoveries from walleye tagged at eastern (A) and western (B) basin spawning sites from 1986 to 28. Modified and updated from Haas et al. 23. Discussion Walleye survival and exploitation estimates produced from tag-recapture data have not been updated for 28 due to problems associated with using old computer programs that are now rendered obsolete by this ever expanding and complex data series. Walleye mortality estimates reported from the 27 annual report represent the most current summary for this data series (Einhouse et al. 28). These previous summaries of walleye mortality components describe high survival rates (> 7 % S) accompanied by a seemingly low natural mortality component for walleye from New York tagging locations. Much more sophisticated tag-recapture analysis software has since been developed and will be used in the event we resume a tagging initiative in the future. This tagging study has been most valuable as an ongoing program for understanding walleye distribution and exploitation rates throughout Lake Erie. These data have also been independently examined in support of three sponsored research projects to improve our understanding of walleye distribution, movements, and mortality on a lake wide scale. From 25 through 27 the ongoing walleye jaw tagging study was expanded to incorporate a PIT tagging component. The walleye PIT tagging study has been a 3-year inter-agency research initiative to independently develop estimates of exploitation and survival without a reliance on voluntary tag returns from fisheries. During 28 the unusual report of 16 tag-recaptures from a single commercial fisherman highlights the need to develop estimates that do not rely on haphazard voluntary tag returns. A secondary objective of this PIT tag initiative is to evaluate tag loss. In the absence of voluntary returns by fishers, the PIT tagging study requires a supplemental effort by agency personnel to examine large numbers of walleye encountered at fish cleaning stations and creel survey locations. These analyses are also the focus of a PhD dissertation by a graduate student candidate attending Michigan State University. At this time New York has suspended both jaw tag and PIT tagging efforts for the foreseeable future, ending 19 consecutive years of participation in this annual walleye tagging program. Although tagging operations will be suspended, active surveillance for jaw tags and PIT tags will continue at least through 29. The jaw tagging study has now seemingly reached a point of diminishing returns for a variety of reasons. Ontario commercial fishers only rarely report jaw tags, tagging in most neighboring Lake Erie jurisdictions has already been suspended, and finally although inter-agency jaw tagging study has yielded a great deal of insight into walleye Section E Page 2

19 NYSDEC Lake Erie Annual Report 28 movements and distribution over many years, at this point other initiatives are now becoming a greater focus for inter-agency collaboration. The much higher cost of PIT tags precludes annual tagging as a standard activity. Instead, PIT tagging may proceed at regular intervals, separated by 2 or more years of only tag surveillance. During 29 we expect to re-direct our previous springtime tagging and recapture data gathering efforts to a new walleye assessment. We plan to expand springtime boat shocker surveys to document additional walleye spawning locations in New York s portion of Lake Erie. The objective of this new initiative is to survey for new spawning walleye locations to recognize habitats of particular significance. Also, we will attempt to ascribe relative abundances to walleye concentrations using an array of spawning locations. References Brownie, C., D. R. Anderson, K. P. Burnham, and D. S. Robson Statistical inference from band recovery data: a handbook. U.S. Department of Interior, Fish and Wildlife Resource Publication No Washington, D.C. Einhouse, D. W. and R. Haas A preliminary examination of walleye distribution and exploitation in the eastern basin of Lake Erie using tag-recapture data. New York Department of Environmental Conservation, Bureau of Fisheries report. November, Einhouse, D. W., J. L. Markham, D. L. Zeller, R. C. Zimar, and B. J. Beckwith 28. NYS DEC Lake Erie 27 Annual Report. New York State Department of Environmental Conservation, Albany, New York. Haas, R. and co-authors. 23. Lake Erie interagency walleye tagging study: 1986 to present. Percis III Symposium. University of Wisconsin Sea Grant Institute, Madison, WI. Section E Page 3

20 NYSDEC Lake Erie Annual Report 28 F. COLDWATER ASSESSMENT SURVEY James L. Markham Rehabilitation of a self-sustaining lake trout population in the eastern basin of Lake Erie continues to be the major thrust of New York=s Great Lakes coldwater fisheries management programs, in cooperation with members of the Lake Erie Committee (LEC), the U.S. Fish and Wildlife Service, and the Biological Research Division of USGS at Sandusky, Ohio. A new lake trout management plan (Markham et al. 28) was approved by the LEC in 28 and will serve as a guide for rehabilitation efforts in the future. New York=s 28 annual lake trout assessment program consisted of: (1) standardized deepwater gill netting in August, and (2) monitoring sea lamprey wounding activity as it impacts lake trout. Additional sampling was also conducted in November to sample eggs and the spawning population. Juvenile lake trout sampling protocols, other than bycatch from forage bottom trawl sampling, continue to be a data void in Lake Erie=s rehabilitation program. Methods A standardized, random design gill net sampling protocol has been employed to assess the lake trout population in the New York waters of Lake Erie since Sampling is conducted in August each year, following lake stratification. LORAN-C lines of position having a relative North/South orientation are used to establish 13 equidistant transects in each of two areas from Dunkirk west to the New York/Pennsylvania boundary. This area delineates summertime lake trout habitat in the New York waters of Lake Erie. Six randomly selected transects in each of the two areas are sampled each season. Five net gangs, or lifts, are fished per night on each transect, yielding a total effort of 6 lifts. However, if bias is encountered (i.e., major thermocline shift overnight), lifts are deleted and/or the entire transect may be reset another day. On any given transect, the first net gang (#1) is fished parallel with shore (on contour), at or below the 5 o F isotherm. Each net gang consists of 1 randomly placed, 5 foot panels of monofilament mesh, ranging from 1.5 to 6. inch by.5 inch increments. Each gang is 5 feet total length. Each of the next three successive net gangs are set on bottom along contours at increments of 5. feet greater depth or.5 miles distance from the previous gang, whichever occurs first, along the transect in a northerly (deeper) direction. All lake trout are processed for total length, weight, sex, maturity, stomach contents, fin clips, and sea lamprey attacks. Snouts are retained from all lake trout for coded-wire tag retrieval and analysis in the laboratory. Otoliths are collected from any lake trout without a clip or coded-wire tag. Secondary targets (i.e. burbot, whitefish, and other salmonids) are processed using the same protocol. Otoliths and/or scales are collected from all secondary targets as needed. November sampling included two net gangs of 5 foot panels of monofilament mesh ranging from 4.5 to 6. inches by.5 inch increments, plus 7. and 8. inch mesh. Each gang was 3 feet total. Nets were placed adjacent to likely spawning rock piles on Brocton Shoal. Two lines of eggs traps made from 5-gallon buckets were also set on top of rock pile ridges on Brocton Shoal in an attempt to determine if lake trout were spawning over this area. The egg traps were made neutral buoyant, which allowed the traps to return to the upright position after strong storm and current events. Each line contained 6 buckets. Klondike strain lake trout are an offshore form from Lake Superior and are thought to behave differently than traditional Lean strain lake trout. They were first stocked in Lake Erie in 24. For assessment purposes, Klondikes are separated out in most analysis in order to detect differences between them and all Lean strain lake trout. Lean strain lake trout include all other strains stocked, including Finger Lakes, Superior, and Lewis Lake. Section F Page 1

21 NYSDEC Lake Erie Annual Report 28 Protocol Changes Several changes in the standard sampling methods and gear have been made since the survey began in These changes are as follows: - Starting in 1995, placement of the fifth or deepest net gang deviated from the previous ( ) protocol. Instead of continuing the above described method of setting progressively deeper gangs, the fifth gang is now set 5 feet deeper than the shallowest gang (#1) or 1. mile distance from the fourth gang, whichever occurred first. This modification was made with hopes of intercepting lake trout that may have moved deeper, in response to greater light penetration. - In 1996, the standard sampling protocol was changed by using monofilament as the standard webbing, replacing the multifilament webbing. This change followed two years of comparison netting that found no significant difference in lake trout catchability between the two types of webbing material (Culligan et al. 1997). - In 1996, one 5 foot panel each of 7. and 8. inch mesh of the standard type were added to each net gang to promote the capture of older-aged lake trout. Fish collected in these samples are used to supplement length, weight, maturity and sea lamprey wounding data. Results Total unbiased gill net assessment of the lake trout population residing in New York=s portion of Lake Erie in 28 sampled 63 individuals in 6 lifts. This was the most lake trout ever caught in the August gill net assessment survey. Seventeen age classes, ranging from age 1 to 24, were represented in the sample of 493 known-aged fish (Tables F.1 and F.2). Similar to the past seven years, young lake trout ages 2-5 were the most abundant cohorts, representing over 95% of the total catch. Cohorts older than age 7 remain in very low abundance. However, three age 24 lake trout were sampled, which were the oldest lake trout ever caught in the survey. TABLE F.1. Number, mean total length (inches TL), mean weight (lbs.), and percent maturity of known age and sex lake trout (Lean strain) by age class collected in gill nets (all gear types) from New York waters of Lake Erie, August 28. AGE SEX NUMBER 2 Male Female 3 Male Female 5 Male Female 6 Male Female 7 Male Female 8 Male Female 9 Male Female 11 Male Female 12 Male Female 14 Male Female 15 Male Female 17 Male Female 18 Male Female 21 Male Female 23 Male Female 24 Male Female MEAN LENGTH (inches TL) MEAN WEIGHT (pounds) PERCENT MATURE TABLE F.2. Number, mean total length (inches TL), mean weight (lbs.), and percent maturity of known age and sex lake trout (Klondike strain) by age class collected in gill nets (all gear types) from New York waters of Lake Erie, August 28. AGE SEX NUMBER MEAN LENGTH MEAN WEIGHT PERCENT MATURE (inches TL) (pounds) 2 Male Female Male Female Male Female Growth and Maturity Mean lengths-at-age and mean weights-at-age of sampled Lean strain lake trout remain consistent with averages from the previous 1 years ( ) up to age 9 (Figures F.1 and F.2). Low sample sizes contributed to variation in mean length and weights in the older age groups. Mean length and weight of Klondike strain lake trout remain lower compared to Lean strain lake trout at ages 4 and 5. Both mean Section F Page 2

22 NYSDEC Lake Erie Annual Report 28 Mean Length (inches TL) Leans - 28 Klondikes Age FIGURE F.1. Mean length-at-age of lean strain and Klondike strain lake trout collected in gill nets from New York waters of Lake Erie, August 28, and the 1-year average from for current growth rate comparison. Mean Weight (lbs) Leans - 28 Klondikes Age FIGURE F.2. Mean weight-at-age of lean strain and Klondike strain lake trout collected in gill nets from New York waters of Lake Erie, August 28, and the 1-year average from for current growth rate comparison. length and mean weight of Klondike strain fish were significantly less at age-5 (two sample t-test; P<.1) compared to the paired stocking of FL strain lake trout. Maturity rates of Lean strain lake trout remained consistent with past years where males are nearly 1% mature by age 4 and females by age 5 (Table F.1). Klondike strain lake trout appear to have similar maturity rates to Lean strain fish in Lake Erie at ages 4 and 5 (Table F.2). Overall Abundance The relative abundance of lake trout caught in standard size meshes of " has been on a general increase since its time series low in 2. Overall abundance in 28 in New York waters was 8.6 lake trout/lift, which was the highest value in the time series (Figure F.3) and above the Objective 1 target (8 fish/lift) established in the lake trout CPE (Number per lift) Basinwide New York Target Average Year FIGURE F.3. Catch per effort (number fish/lift) and confidence limits (approximated as 2 SE s) of lake trout caught in standard assessment gill nets from New York waters of Lake Erie, August Basinwide abundance, target basinwide abundance, and NY series average are also shown. management plan (Markham et al. 28). Basinwide abundance, however, is still well below the target level. Burbot abundance increased slightly in 28 following a sharp decline in 27. Overall burbot abundance in 28 was estimated at 2.4 fish/lift, which was slightly higher than the time series average of 2.1 fish/lift (Figure F.4). Burbot abundance has declined over 5% since 24. CPE (Number per lift) Year FIGURE F.4. Catch per effort (number fish/lift) and confidence limits (approximated as 2 SE s) of burbot caught in standard assessment gill nets from New York waters of Lake Erie, August Dashed line indicates time series average. Whitefish catches continue to be highly variable in this survey, both between years and within years. After declining to near zero in 26, whitefish abundance increased to 11.7 fish/lift in 27, its highest level in the time series, due to catches from the dominant 23 year class. Whitefish abundance declined in 28 to 6.1 fish/lift, but remains at its fourth highest value in the time series and well above average (Figure F.5). Other notable species caught during the survey include 1 Coho salmon, 7 brown trout, and 29 walleye. The relative abundance of lake trout by age of the Section F Page 3

23 NYSDEC Lake Erie Annual Report 28 CPE (Number per lift) CPE (Number per lift) Basinwide New York Target Average Year FIGURE F.5. Catch per effort (number fish/lift) and confidence limits (approximated as 2 SE s) of whitefish caught in standard assessment gill nets from New York waters of Lake Erie, August Dashed line indicates time series average. 28 standard gill net assessment catch illustrates the higher abundance of the younger cohorts between the ages of 2 and 5, and the absence of age 8 and older age-classes (Figure F.6). Klondike strain lake trout comprise all of the age 4 lake trout, which was the most abundant age-class sampled and represented over half of all the lake trout caught, and 54% of the age 5 age-class. Younger age-classes have dominated the catches since 22. The abundance of older lake trout (age 1+) has declined from over 3% of the total abundance in 21 to only 1.9% in 28. CPE( Number per Lift) Klondikes Leans Age FIGURE F.6. Relative abundance by age of lake trout collected from standard assessment gill nets fished in New York waters of Lake Erie, August 28. A lift consists of ten 5 foot panels of variable mesh size (1.5-6 inches). Klondike strain lake trout are shown in yellow bars. Adult Abundance The relative abundance of age 5 and older lake trout nearly doubled from 1.5 fish/lift in 27 to 2.9 fish/lift in 28 (Figure F.7). This was the fourth highest adult abundance in the time series and well above the average of 1.6 fish/lift. The adult abundance in New York waters is also above the Objective 2 target (2. fish/lift) established in the Year FIGURE F.7. Relative abundance of age 5 and older lake trout collected from standard assessment gill nets fished in New York waters of Lake Erie, August A lift consists of ten 5 foot panels of variable mesh size (1.5-6 inches). Confidence intervals are approximated as 2 SE s. Basinwide abundance, target basinwide abundance, and NY series average are also shown. lake trout management plan (Markham et al. 28). However, overall basinwide adult abundances remain well below target levels. The CPE of mature females >45g in Lake Erie, representing mature, repeat spawning fish, was.47 fish/lift in 28 (Figure F.8). This is above the series average of.34 fish/lift, but remains below the targets established in the lake trout management plan (.5 fish/lift) (Markham et al. 28). Again, basinwide abundance of mature females >45g is much less than the abundance in New York waters. CPE( Number per Lift) Basinwide New York Target Average FIGURE F.8. Relative abundance of all mature females >45g from standard assessment gill nets in New York waters of Lake Erie, August Basinwide abundance, target basinwide abundance, and NY series average are also shown. Recruitment The success of stocking is measured by the recruitment of age 2 fish. Lake trout that have survived from stocking to age-2 have adapted to the lake environment and have sufficiently grown out of Section F Page 4

24 NYSDEC Lake Erie Annual Report 28 the range of most lake predators. Abundance at age- 2 is a strong indication of abundance at older age classes. The age 2 recruitment index, which is an abundance index of survival to age 2 standardized for the number of stocked yearlings, increased to.53 in 28 (Figure F.9). This was the fourth highest recruitment index in the time series and the third time in the past six years with above-average recruitment. Much of the recruitment success in 25, 26, and 28 is due to Klondike strain lake trout. Age 2 CPE Index Average Age 2 Index FIGURE F.9. Index of recruitment for age 2 lake trout caught in standard assessment gill nets from New York waters of Lake Erie, August The index is equal to the number of age 2 fish caught per lift for every 1, yearling lake trout stocked. Survival Cohort analysis estimates of annual survival (S) were calculated by strain and year class using a 3- year running average of CPE with ages 4 through 1. A running average was used due to the high year-to-year variability in catches. Mean overall adult survival estimates were highest for the Lake Ontario (LO) strain (.81) and lowest for the Superior (SUP) strain (.579) (Table F.3). Survival rates for the Lake Erie (LE) strain were also high (.788), but this was based upon only two year classes with relatively poor returns. The Finger Lakes (FL) strain, the most consistently stocked lake trout strain in Lake Erie, had an overall mean survival estimates of.779. Survival estimates prior to 1986 are low due to the effects of a large sea lamprey population. Survival of the year classes were comparably higher as the sea lamprey population declined and the number of adult lake trout increased, decreasing the affect of host density. Survival estimates during this period ( ) were highest for the FL strain (.83) and lowest for the SUP strain (.79). The LO TABLE F.3. Cohort analysis estimates of annual survival (S) by strain and year class for lake trout caught in standard assessment nets in the New York waters of Lake Erie, Threeyear running averages of CPE from ages 4 1 were used due to year-to-year variability in catches. Shaded cells indicate survival estimates that fall below the.6 target rate. Asterisk (*) indicates years where straight CPE s were used for ages 4-9 (SUP 1999), 5-9 (FL 1999), 4-8 (SUP 2), or 4-7 (SUP 21). STRAIN Year Class LE LO LL SUP FL * *.5 21*.213 MEAN strain, a cross between SUP and FL strains, was intermediate at.81. Survival estimates declined again beginning with the 1992 year class as the lamprey population increased. Mean overall survival estimates for all strains were above the target goal of 6% or higher (Lake Trout Task Group 1985; Markham et al. 28) except for the LL and SUP strains. More recent estimates of survival indicate that survival may have declined well below target levels due to sea lamprey predation. Survival estimates of the year classes of SUP strain lake trout range from Survival estimates from the 1996, 1997, and 1999 FL strain are much higher, but are based on very low returns. All of these survival estimates are below the ranges that were observed for these strains during the period of high-lamprey control. Strains Eight different lake trout strains were found in the 558 fish caught with hatchery-implanted coded-wire tags (CWT=s) or fin-clips (Table F.4). Klondike Section F Page 5

25 NYSDEC Lake Erie Annual Report 28 TABLE F.4. Number of lake trout per stocking strain by age collected in gill nets from New York waters of Lake Erie, August 28. Stocking strain codes are: FL = Finger Lakes, LE = Lake Erie, LL = Lewis Lake, LO = Lake Ontario, SUP = Superior, KL = Klondike, SI = Slate Island, TI = Traverse Island. Shaded cells indicate ages strain was stocked. AGE FL LE LL LO SUP KL SI TI TOTAL (KL) and Finger Lakes (FL) strains remain the most numerous strains caught in Lake Erie in 28. Klondike strain lake trout have only been stocked in Lake Erie in low amounts for four of the last five years while the Finger Lakes strain has been the most numerous and consistent strain stocked. Numbers of Superior (SUP) strain lake trout, also commonly stocked and the most prevalent strain a few years ago, continue to decline rapidly in Lake Erie. Only five SUP strain fish were sampled in 28 compared to 167 in 24. All other Lean lake trout strains (LE, LL, LO, SI, TI) remain minor contributors to the Lake Erie stock. The FL strain remains the most prevalent lake trout strain caught at older ages. All lake trout over age 11 were either FL strain fish or FL strain crosses (LE, LO strain) with the exception of one LL strain fish. TABLE F.5. Frequency of occurrence of diet items from nonempty stomachs of lake trout and burbot collected in gill nets from New York waters of Lake Erie, August 28. PREY SPECIES Lean Lake Trout (N = 155) Klondike Lake Trout (N =164) Burbot (N =88) Smelt 127 (82%) 122 (74%) 15 (17%) Yellow Perch 1 (1%) 1 (1%) White Perch 1 (1%) Emerald Shiner 1 (1%) 2 (2%) Gizzard Shad 1 (1%) Round Goby 46 (3%) 59 (36%) 84 (95%) Unknown Fish 7 (5%) 9 (5%) 13 (15%) Mudpuppy 1 (1%) Number of Empty Stomachs Diet Analysis of the stomach contents of lake trout and burbot revealed diets almost exclusively comprised of fish in both species (Table F.5). Rainbow smelt, the longtime main prey item for lake trout, was the most prevalent diet item found in both Lean (82%) and Klondike (74%) strain lake trout stomachs. Round gobies increased from 21% occurrence in 27 in Lean strain lake trout to 3% in 28, but declined from 44% to 36% in Klondike strain fish (Figure F.1a and F.1b). Despite the decline in occurrence in Klondike strain lake trout, round gobies still represent a significant portion of the diet of lake trout and do offer alternative forage to smelt. Yellow perch, white perch, and one mudpuppy were the only other identifiable diet items found in lake trout stomachs. This was the first time a mudpuppy was found in a lake trout stomach. % Occurrence % Occurrence A. Lean Lake Trout Smelt Gobies B. Klondike Lake Trout Smelt Gobies FIGURE F.1. Percent occurrence of smelt and round gobies in the diet of lake trout (Lean and Klondike strain) caught in assessment gill nets in the New York waters of Lake Erie, August, Section F Page 6

26 NYSDEC Lake Erie Annual Report 28 Round gobies continue to be the major food item for burbot, occurring in 95% of the 88 non-empty burbot stomachs examined (Table F.5; Figure F.11). Smelt were a distant secondary diet species (17%). This was the highest occurrence of gobies and the lowest occurrence of smelt found in burbot stomachs since round gobies appeared in 2. All other prey items (yellow perch, emerald shiner, gizzard shad) were infrequent components of the burbot diet. 1 Burbot Smelt Gobies % Occurrence FIGURE F.11. Percent occurrence of smelt and round gobies in the diet of burbot caught in assessment gill nets in the New York waters of Lake Erie, August, Gill Nets Egg Traps FIGURE F.12. Gill net and egg trap survey locations sampled for lake trout spawning on Brocton Shoal and Van Buren Bay in the eastern basin of Lake Erie, November 28. temperatures ranged from 51F at setting to 44F at pickup. No lake trout eggs were collected in the 12 egg trap buckets. However, 58 bloody red shrimp (Hemimysis), a new invasive species, were collected. The majority (48) of the Hemimysis were found in two traps, but seven of the 12 traps contained at least one of the new invader. Spawning and Egg Trap Surveys Only one overnight gill net set targeting spawning lake trout was accomplished in 28 due to poor weather conditions. Two net gangs were set on both Brocton Shoal (offshore, deep) and Van Buren Reef (nearshore, shallow) on 5 November 28 and pulled the following day (Figure 12). Bottom water temperatures at both locations were 51F, which should have been optimal for lake trout spawning. Only 1 lake trout were caught in total; three on Brocton Shoal and seven on Van Buren Reef. Six of the lake trout were females and four males, and all of the fish were hard (unripe) with the exception of one male. The lake trout were all age-6 Finger Lakes strain fish with the exception of one age-5 and one age-7 fish. One female s eggs were undeveloped, presumably due to an A1 sea lamprey wound. Other species caught included catfish, gizzard shad, smallmouth bass, and walleye. Two egg trap lines were set on raised rock ridges (i.e. suspected spawning areas) on Brocton Shoal on 5 November 28 and picked up on 24 November 28 (Figure 12). The traps were set to determine if lake trout were spawning over these areas. Water Discussion The 28 coldwater assessment survey revealed dramatic increases in the lake trout population in the New York waters of Lake Erie. Overall abundance increased 4% over 27, mainly due to the large returns of the age-4 Klondike strain fish. Adult stocks are also showing signs of rebuilding, although at a slower pace. Abundance of lake trout in New York waters is approaching or has exceeded some of the metrics established in the lake trout management plan, but basinwide abundance remains well short of rehabilitation goals. Klondike strain lake trout continue to show promise in Lake Erie. Despite being stocked in low numbers in four of the past five years, they are now the most common lake trout strain in the population. Abundance estimates of the 24 year class at age-4 were the highest on record, and the high returns of the sparsely-stocked 23 year class at age-5 is partially responsible for the increase observed in the adult (age 5+) population. Recruitment of age-1 and age-2 Klondikes continues to be higher than Lean Section F Page 7

27 NYSDEC Lake Erie Annual Report 28 strains stocked at the same time. While maturity rates on this strain appear to be similar in Lake Erie to Lean strain lake trout, growth rates are slower with differences of nearly three inches and three pounds, on average, by age-5. Wounding rates on age-5 Klondikes were over 3 times higher than on age-5 Finger Lakes strain lake trout in 28, indicating that they may be susceptible to sea lamprey attacks despite their smaller size. Results from the limited gill net and egg trap lake trout spawning surveys were disappointing. Brocton Shoal has been identified as a historic spawning site for lake trout (Edsall et al. 1992), but this survey along with others conducted in the late-199s and in 21 found similar results: lake trout are not using this historical site and more lake trout tend to use the inshore areas around Van Buren Reef. Underwater cameras reveal that the rock piles on Brocton Shoal are not clean with deep interstitial spaces as Edsall et al. (1992) described, but are extensively covered in mats of quagga mussels to the point where single rocks are hardly distinguishable. The possibility exists that past spawning sites in Lake Erie that were once ideal for lake trout production, such as Brocton Shoal, are no longer viable habitats for spawning and rearing. If lake trout are not utilizing Brocton Shoal as a spawning ground, then several more questions need to addressed: 1) Are lake trout spawning? 2) If so, where are they spawning? and 3) What is this habitat like and why is it better? Further spawning survey work and mapping of possible spawning areas, as suggested by Thibodeau and Kelso (199), are required to determine where the most effort should be expended to develop naturally spawning populations. References Culligan, W. J., F. C. Cornelius, D. W. Einhouse, D. L. Zeller, R. C. Zimar, B. J. Beckwith, and M. A. Wilkinson NYSDEC Lake Erie 1997 Annual Report to the Lake Erie Committee. New York Department of Environmental Conservation, Albany. Edsall, T.A., Brown, C.L., Kennedy, G.W., and French, J.R.P., III Surficial substrates and bathymetry of five historical lake trout spawning reefs in nearshore waters of the Great Lakes. Great Lakes Fish. Comm. Technical Report 58. Lake Trout Task Group A Strategic Plan for the Rehabilitation of Lake Trout in Eastern Lake Erie. Report to the Great Lakes Fishery Commission=s Lake Erie Committee, Ann Arbor, Michigan, USA. Markham, J., A. Cook, T. MacDougall, L. Witzel, K. Kayle, C. Murray, M. Fodale, E. Trometer, F. Neave, J. Fitzsimons, J. Francis, and M. Stapanian. 28. A strategic plan for the rehabilitation of lake trout in Lake Erie, Lake Erie Committee, Great Lakes Fisheries Commission, Ann Arbor, MI. Available at ocs/manplan28.pdf [accessed 14 January 28]. Thibodeau, M.L., and Kelso, J.R.M An evaluation of putative lake trout (Salvelinus namaycush) spawning sites in the Great Lakes. Canadian Technical Report of Fisheries and Aquatic Sciences No Section F Page 8

28 NYSDEC Lake Erie Annual Report 28 G. SEA LAMPREY ASSESSMENT James L. Markham Sea lamprey invaded Lake Erie and the Upper Great Lakes in the 192's with the opening of the Welland Canal connecting Lakes Erie and Ontario. Although not totally to blame for the ultimate demise of the lake trout population in Lake Erie, they undoubtedly played an integral part in the eventual failure of the original stocks. Populations of lampreys were left untreated in Lake Erie until the Strategic Plan for Lake Trout Restoration in Eastern Lake Erie document was formulated in 1985 (Lake Trout Task Group 1985a) that pointed to the lack of lamprey treatment as a bottleneck in the establishment of a lake trout population. The Sea Lamprey Management Plan for Lake Erie (Lake Trout Task Group 1985b) followed with a set of goals to achieve lamprey control. Since 1986, the Great Lakes Fisheries Commission has conducted regular treatments of key Lake Erie tributaries in order to control lamprey populations and the damage they inflict on the Lake=s coldwater fishery resources to accomplish these management goals. Methods Lake trout are the only Lake Erie salmonine species used for sea lamprey wounding observations due to availability. More recently, sea lamprey wounds on burbot are also reported due to their population decline. Samples are obtained from deepwater gill net assessments targeting lake trout, burbot and other coldwater species during August along New York=s portion of Lake Erie from Dunkirk westward to the New York/Pennsylvania boundary. Sea lamprey wounds are classified as A1-A4 for evidence of active feeding and as B1-B4 wounds for non-active feeding, according to King and Edsall (1979). Wounding frequencies on lake trout are reported as the number of fresh (A1-A3) wounds per 1 fish. A1 and A4 wounds, specifically, are tabulated under the same criteria as evidence of the current and previous year=s wounding, respectively. Data are tabulated using standard total length categories: inches, inches, inches, and all fish greater than 29 inches. Burbot wounding rates are reported for fresh (A1-A3) and A4 wounds on all individuals. Sea lamprey nest counts are also conducted annually on standard sections of four streams: Delaware Creek, Clear Creek, North Branch of Clear Creek, and Canadaway Creek - between June 1 and June 15. Counting surveys begin following peak catches in portable assessment traps operated on Cattaraugus Creek at the base of Springville Dam and at Spooner Creek under contract with the U.S. Fish and Wildlife Service. All Clear Creek count sites are located on Seneca Nation of Indians= lands, and activities there are conducted with permission of the Seneca Nation. Results A total of 34 A1-A3 wounds were found on 55 lake trout greater than 21 inches total length in 28, equaling a wounding rate of 6.7 wounds per 1 fish (Table G.1; Figure G.1). This was a 6% decline from the 27 wounding rate (16.5 wounds/1 fish) and the lowest sea lamprey wounding rate in the last six years. Despite the decline, the wounding rate is still slightly higher than the target rate of 5 wounds per 1 fish (Lake Trout Task Group 1985b). Wounding rates have remained above target for 13 of the past 14 years following relaxed lamprey control measures in the mid 199 s (Sullivan et al. 23). Lake trout >29 inches continue to be prime targets for sea lampreys, but smaller lake trout in the inch category received the highest percentage of TABLE G.1. Frequency of sea lamprey wounds observed on several standard length groups of lake trout collected from gill nets in New York waters of Lake Erie, August 28. SIZE CLASS TOTAL LENGTH (inches) SAMPLE SIZE WOUND CLASSIFICATION A1 A2 A3 A4 NO. A1-A3 WOUNDS PER 1 FISH NO. A4 WOUNDS PER 1 FISH > > Section G Page 1

29 NYSDEC Lake Erie Annual Report 28 Wounds per 1 Fish Lake Trout >21 Inches A1-A3 Target The post-treatment average includes 1987 through 27. fish) to 35.4 wounds/1 fish in 28 (Figure G.3). This was the lowest A4 wounding rate in the last four years but still above the time series average of 25.1 wounds/1 fish. Similar to past surveys, the majority of the A4 wounds were found on fish greater than 25 inches in total length (Table G.1). A4 wounding rates on lake trout >29 inches in length remain very high (13 wounds/1 fish) with many fish possessing multiple wounds FIGURE G.1. Number of fresh (A1-A3) sea lamprey wounds per 1 adult lake trout greater than 21 inches sampled in gill nets from New York waters of Lake Erie, August - September, The Strategic Plan target rate is 5%. fresh wounds (Table G.1). This was the second consecutive year and only the third year since 1988 that sea lamprey wounds were found on lake trout less than 21 inches. Fresh A1 wounds are considered indicators of the attack rate for the current year at the time of sampling (August). A1 wounding in 28 was 1.4 wounds per adult lake trout greater than 21 inches, which was the lowest rate since 22 and below the series average of 2.26 wounds/fish (Table G.1; Figure G.2). A total of nine A1 wounds were found spread across all size categories. The past year=s cumulative attacks are indicated by A4 wounds. A4 wounding rates continued to decline from the time series high in 26 (77.4 wounds/ 1 Wounds per 1 Fish Lake Trout >21 Inches A1 Average FIGURE G.2. Number of fresh (A1) sea lamprey wounds per 1 adult lake trout greater than 21 inches sampled in gill nets from New York waters of Lake Erie, August - September, Wounds per 1 Fish Lake Trout >21 Inches A4 Average FIGURE G.3. Number of healed (A4) sea lamprey wounds observed per 1 adult lake trout greater than 21 inches sampled in gill nets from New York waters of Lake Erie, August, The post-treatment average includes 1987 through 27. Finger Lakes (FL) and Klondike (KL) strain lake trout were the most prevalent strains sampled and accounted for all the fresh (A1-A3) sea lamprey wounds and the majority of the A4 wounds (Table G.2). Overall A1-A3 and A4 wounding rates were higher on Finger Lakes strain compared to Klondike strain lake trout. A4 wounding rates were very high on other lake trout strains (Lake Erie, Lewis Lake, Lake Ontario, Superior) due to low sample sizes and multiple wounds per fish. TABLE G.2. Frequency of sea lamprey wounds observed on lake trout >21 inches, by strain, in New York waters of Lake Erie, August 28. LAKE TROUT STRAIN SAMPLE SIZE WOUND CLASSIFICATION A1 A2 A3 A4 NO. A1-A3 WOUNDS PER 1 FISH NO. A4 WOUNDS PER 1 FISH FL KL LE LL LO SUP Section G Page 2

30 NYSDEC Lake Erie Annual Report 28 Populations of burbot, once the most prevalent coldwater predator, have declined to less than half the numbers seen only a few years ago across the eastern basin of Lake Erie (CWTG 28). Both A1- A3 and A4 wounding rates on burbot have increased since 21 in the New York waters of Lake Erie. The fresh wounding rate on burbot declined in 28 from a time series high in 27, but A4 wounding rates continued a 4-year increasing trend to a time series high of 15.6 wounds/1 fish (Figure G.4). Wounds per 1 Fish Burbot A1-A FIGURE G.4. Number of A1-A3 and A4 sea lamprey wounds per 1 burbot (all sizes) sampled in gill nets from New York waters of Lake Erie, August, Sea lamprey nest counts occurred between 6 June and 12 June, 28. The overall index for sea lamprey nesting decreased for the first time since 24 to 15.7 nests/mile (Figure G.5). This was a A4 64% decline over the 27 nesting rate of 43.1 nests/mile and below the time series average of 17.2 nests/mile. The highest nest counts were once again found in the main branch of Clear Creek (91 nests; 22.8 nests/mile), a tributary to Cattaraugus Creek (Table G.2). This was a decline of 61% over the 27 nest density of 59. nests/mile. Sea lamprey nesting rates also declined sharply on Canadaway Creek with only 1 nest found in.8 miles of creek (1.3 nests/mile). More typical rates were found on North Branch of Clear Creek while no nests were found for the second consecutive year on Delaware Creek. Density (nests/mile) Nest Density Average FIGURE G.5. Sea lamprey nest density (nests/mile) from standard stream sections on New York tributaries of Lake Erie, No sampling was conducted in The posttreatment average includes 1987 through 27. TABLE G.3. Individual and overall indices of sea lamprey nest density (nests/mile) from standard stream sections on New York tributaries of Lake Erie, YEAR STD. STREAM SECTION Mile Delaware Creek N/A Clear Creek * N/A N. Br. Clear Creek N/A Canadaway Creek N/A OVERALL YEAR STD. STREAM SECTION Mile Delaware Creek ** Clear Creek N. Br. Clear Creek ** Canadaway Creek OVERALL Section G Page 3

31 NYSDEC Lake Erie Annual Report 28 Discussion While fresh wounding rates remain above target levels and A4 wounding rates remain above average, all of the indicators point to a decline in sea lamprey abundance in Lake Erie. A1-A3 wounding rates declined 6% compared to 27 while A4 wounding rates have declined 54% since 26. Sea lamprey nest densities declined over 6% in the past year as well. The decline comes after two consecutive years of lampricide treatments on Cattaraugus Creek, a main producer of sea lampreys in Lake Erie, and the first round of back-to-back lampricide treatments of all key Lake Erie tributaries. These treatments are expected to reduce sea lamprey wounding to below target levels by 21 in Lake Erie, and hopefully help trigger a resurgence of the adult lake trout population. The lack of large lake trout >29 inches and the high abundance of smaller lake trout has increased the wounding rates in the smaller size categories. Until this year, lake trout >25 inches, and especially those >29 inches, have been targeted by sea lampreys. Over time, the abundance of larger lake trout (age 1+) has declined from over 3% of the total abundance in 21 to less than 3% in 27 (Einhouse et al. 28). With less available large targets, smaller sized lake trout have seemingly become more susceptible to wounding. This trend should reverse itself once the adult lake trout population builds again, but stresses the importance of continued sea lamprey control to lake trout rehabilitation efforts. The susceptibility of Klondike strain lake trout to sea lamprey attacks remains in question. Overall results indicate that Klondikes are equal or less impacted by sea lamprey wounding than Finger Lakes strain fish, which are thought to be the best strain for avoiding lampreys (Schneider et al. 1996). However, Klondikes have only recently been stocked (see Section H) and have slower growth rates (see Section F), and therefore have not obtained the larger sizes targeted by sea lampreys. It is possible that Klondike strain lake trout will be less susceptible to wounding due to their slower growth as long as other larger lake trout (i.e. preferred targets) are available, but several years more of wounding statistics are needed. References CWTG. 28. Report of the Lake Erie Coldwater Task Group, March 28. Presented to the Standing Technical Committee, Lake Erie Committee of the Great Lakes Fishery Commission. Ann Arbor, Michigan, USA. Einhouse, D.W., J.L. Markham, K.L. Kapuscinski, M.L. Wilkinson, M.T. Todd, D.L. Zeller, R.C. Zimar, and B.J. Beckwith. 28. NYSDEC Lake Erie 27 Annual Report to the Lake Erie Committee. New York Department of Environmental Conservation, Albany. King, L.E., Jr. and T.A. Edsall Illustrated Field Guide for the Classification of Sea Lamprey Attack Marks on Great Lakes Lake Trout. Great Lakes Fishery Commission, Special Publication 79-1, Ann Arbor, Michigan. 41 pp. Lake Trout Task Group. 1985a. A Strategic Plan for the Rehabilitation of Lake Trout in Eastern Lake Erie. Report to the Great Lakes Fishery Commission=s Lake Erie Committee, Ann Arbor, Michigan, USA. Lake Trout Task Group. 1985b. A Sea Lamprey Management Plan for Lake Erie. Report to the Great Lakes Fishery Commission=s Lake Erie Committee, Ann Arbor, Michigan, USA. Schneider, C.P., R.W. Owens, R.A. Bergstedt, and R. O Gorman Predation by sea lamprey (Petromyzon marinus) on lake trout (Salvelinus namaycush) in southern Lake Ontario, Canadian Journal of Fisheries and Aquatic Sciences 53(9): Sullivan, W.P., G.C. Christie, F.C. Cornelius, M.F. Fodale, D.A. Johnson, J.F. Koonce, G.L. Larson, R.B. McDonald, K.M. Mullett, C.K. Murray, and P.A. Ryan. 23. The sea lamprey in Lake Erie: a case history. Journal of Great Lakes Research 29 (Supplement 1): Section G Page 4

32 NYSDEC Lake Erie Annual Report 28 H. 28 SALMONINE STOCKING SUMMARY James L. Markham and Michael A. Wilkinson New York has been regularly stocking salmonids into Lake Erie since 1968 when the first coho salmon were introduced. The initial introductions were made to control excessive alewife and rainbow smelt populations that existed (Crawford 21). Eventually, most salmonid stockings were continued to support declining sport fish populations and to utilize the sparsely inhabited hypolimnion (Cornelius, NYSDEC, personal communication). The one exception is lake trout, which have been stocked since the mid-197's in an effort to rehabilitate this once-native species. Pacific salmon are no longer stocked into Lake Erie by any agency and the majority of the stocking effort is concentrated on steelhead and lake trout. Results and Discussion The 458,551 salmonines stocked into New York=s waters of Lake Erie was 3.1% above the proposed 28 stocking of 445, fish, marking the second consecutive year that actual stocking reached overall stocking goals (Table H.1). However, not all species reached their stocking goal while others had surplus fish stocked. Overall, stocked numbers of brown, rainbow, and steelhead trout have remained around 3, yearlings annually since 1998 (Figure H.1). Yearling Equivalents (thousands) Coho Chinook Brown trout Dom. Rainbow trout Steelhead FIGURE H.1. Number (in yearling equivalent units) of Pacific salmon, brown trout, and rainbow trout (domestic and steelhead) stocked in New York waters of Lake Erie, The current lake trout stocking goal (16, yearlings) was met for the first time since 23 (Table H.1; Figure H.2). A total of 152,751 yearlings were stocked into New York waters while 5, surplus Lake Manitou strain fish were stocked by the Ontario Ministry of Natural Resources off Port Maitland. Combined, the 22,751 yearlings were the most lake trout stocked into Lake Erie waters since Since the Allegheny National Fish Hatchery (ANFH) remained closed for renovations, lake trout stocked in New York waters were raised at two federal facilities in Vermont (White River and Pittsford National Fish Hatcheries) and stocked between 29 April and 7 May, 28. All lake trout were stocked offshore of Dunkirk in approximately 7 feet of water via the R/V ARGO. The majority of the lake trout were Finger Lakes strain fish with lesser numbers of Klondike strain also stocked. The Vermont hatcheries are scheduled to raise lake trout for Lake Erie until renovations at the ANFH are complete. Current projections for resuming production at the ANFH have been pushed back to 212 due to lack of funds. Yearlings Stocked SUPERIOR FINGER LAKES LEWIS LAKE LAKE ONTARIO LAKE ERIE KLONDIKE OTHERS FIGURE H.2. Yearling lake trout stocked (in yearling equivalents) in eastern basin waters of Lake Erie, , by strain. Stocking goals through time are shown by dark lines. The current stocking goal is 16, yearlings per year. Steelhead remain the most numerous salmonid species stocked with 264,8 yearlings stocked in 8 tributaries (Tables H.1 and H.2; Figure H.1). All of the Lake Erie tributaries received their stocking goal Section H Page 1

33 NYSDEC Lake Erie Annual Report 28 or more in 28. Warm weather and low water conditions forced the stockings from Buffalo Creek, Cayuga Creek, and Cazenovia Creek to be moved to the lower stretches of the Buffalo River. Surplus steelhead were stocked in Cattaraugus Creek (27,8 surplus yearlings), 18 Mile Creek (2,), and the Buffalo River (5,). Surplus Skamania strain (9,8) were again available and stocked for the fourth consecutive year in Cattaraugus Creek. These fish were double clipped (LPAD) for future identification. A small number of domestic rainbows (5,) were also stocked in 18 Mile Creek for the fourth straight year to supplement the steelhead runs in this popular tributary. Lastly, a total of 36, yearling brown trout were split between Barcelona Harbor, Dunkirk Harbor, Cattaraugus Creek, and Big Sister Creek. Stocking numbers of brown trout remain shy of the stocking goal (45, yearlings) due to shortages within the New York hatchery system. The cooperative pen-rearing project in Dunkirk Harbor with the Lake Erie Salmon and Trout Association was permanently cancelled in 28 due to poor harbor water conditions and failures in two of the previous three years. The 1, steelhead scheduled for the net pens were moved to Walnut and Silver Creeks (5, fish per creek). Late stocking dates, warm weather, and low water conditions also hampered the net pen project conducted by the Bison City Rod and Gun Club in the lower Buffalo River. A total of 1,8 steelhead of the scheduled 1, were put into the pens on 23 April for educational purposes, and these fish were released after only one week. Growth was determined to be negligible. The project is scheduled to continue in 29. References Crawford, S.S. 21. Salmonine introductions to the Laurentian Great Lakes: an historical review and evaluation of ecological effects. Canadian Special Publication of Fisheries and Aquatic Sciences pp. Section H Page 2

34 NYSDEC Lake Erie Annual Report 28 TABLE H.1. Summary of trout stocking in New York waters of Lake Erie in 28. Species Location Date Stk YC Hatchery Strain Mos Stage #/lb. Clip/Mark Num Stk. Proposed - 27 Lake Trout Dunkirk 4/29/8 27 PNFH Finger Lakes 16 Ylg 9.7 AD/ ,85 Lake Trout Dunkirk 4/3/8 27 PNFH Finger Lakes 16 Ylg 9.7 AD/ ,125 Lake Trout Dunkirk 4/3/8 27 PNFH Finger Lakes 16 Ylg 11 AD/ ,33 Lake Trout Dunkirk 5/1/8 27 PNFH Finger Lakes 16 Ylg 11 AD/ Lake Trout Dunkirk 5/1/8 27 PNFH Finger Lakes 16 Ylg 11 AD/ ,892 Lake Trout Dunkirk 5/5/8 27 PNFH Finger Lakes 16 Ylg 11 AD/ ,35 Lake Trout Dunkirk 5/6/8 27 PNFH Finger Lakes 16 Ylg 11 AD/ , Lake Trout Dunkirk 5/6/8 27 WRNFH Klondike 16 Ylg 7.2 AD/6189 9,593 Lake Trout Dunkirk 5/7/8 27 WRNFH Klondike 16 Ylg 7.2 AD/ ,186 Lake Trout Totals Lake Trout Yearlings 152,751 16, Brown Trout Dunkirk Harbor 4/28/8 27 RSFH Domestic 16 Ylg 3.7 None 16, 2, Brown Trout Barcelona Harbor 4/15/8 27 RSFH Domestic 16 Ylg 4.2 None 8, 1, Brown Trout Mouth - Cattaraugus Creek 4/24/8 27 RSFH Domestic 16 Ylg 3.6 None 8, 1, Brown Trout Big Sister Creek 5/1/8 27 CSFH Domestic 16 Ylg 3.4 None 4, 5, Brown Trout Totals Brown Trout Yearlings 36, 45, Rainbow Trout Walnut Creek 4/28/8 27 SRSFH Washington 12 Ylg 18 None 1, 1, Rainbow Trout Silver Creek 4/28/8 27 SRSFH Washington 12 Ylg 18 None 1, 1, Rainbow Trout Buffalo River 4/23/8 27 SRSFH Washington 12 Ylg 18 None 43,2 35, Rainbow Trout Cattaraugus Cr. 5/1/8 27 SRSFH Washington 12 Ylg 27 None 9,* 72, Rainbow Trout Cattaraugus Cr. 5/1/8 27 SRSFH Skamania 12 Ylg 13 LPAD 9,8* Rainbow Trout 18-Mi. Creek 4/25/8 27 SRSFH Washington 12 Ylg 2 None 2, 2, Rainbow Trout S. Branch 18-Mi. Creek 4/25/8 27 SRSFH Washington 12 Ylg 2 None 2,* 18, Rainbow Trout Canadaway Cr. 4/28/8 27 SRSFH Washington 12 Ylg 2 None 2, 2, Rainbow Trout Chautauqua Cr. 4/29/8 27 SRSFH Washington 12 Ylg 27 None 4, 4, Rainbow Trout Buffalo River (Pen) 5/1/8 27 SRSFH Washington 12 Ylg 18 None 1,8 1, Rainbow Trout 18 Mile Creek 4/1/8 27 CSFH Rand Dom 16 Ylg 4.1 None 5, 5, Rainbow Trout Totals Steelhead Yearlings (Washington Strain) 264,8 235, Rainbow Trout Yearlings (Randolph Strain) 5, 5, TOTAL ALL SPECIES ` 458, , * Includes surplus fish Hatchery Codes: ANFH = Allegheny National Fish Hatchery; RSFH = Randolph State Fish Hatchery; CSFH = Caledonia State Fish Hatchery; SRSFH = Salmon River State Fish Hatchery; BSFH = Bath State Fish Hatchery; Chat = Chatsworth Fish Hatchery, ON; PNFH = Pittsford, VT National Fish Hatchery; WRNFH = White River, VT National Fish Hatchery Section H Page 3

35 NYSDEC Lake Erie Annual Report 28 TABLE H.2. Approximate numbers (x 1) of salmon and trout planted in New York waters of Lake Erie from 1968 through 28. Lake trout numbers include those stocked in Pennsylvania and Ontario waters also. YEAR Species/ Type Coho Y Coho F Coho f Chin f Lake Y Lake F Lake fry Lake adt.1.1 Brwn Y Brwn F Brwn f Rbow Y Rbow F Rbow f Sthd Y Sthd F TOTAL Species/ Type Coho Y Coho F Coho f 8 2 Chin f Lake Y Lake F Lake fry Lake adt Brwn Y Brwn F Brwn f 2 35 Rbow Y Rbow F Rbow f Rbow adt 1.2 Sthd Y Sthd F Sthd f 1 TOTAL Legend: Y=Standard stocked yearling; F=Fall fingerling; f=spring fingerling; fry=advanced yolk-sac/swim-up fry; adt=surplus broodstock Section H Page 4

36 NYSDEC Lake Erie Annual Report 28 I. THE 27 LAKE ERIE SALMONID ANGLER DIARY PROGRAM James L. Markham The Lake Erie angler diary program began in 1983 with the purpose of gaining additional data from the open water and tributary salmonid fishery. It provides a means of monitoring the quality of the salmonid fishery as well as the success of various species and stockings. Catch per effort indices are obtained by individual angler, tributary, and for the overall fishery. Methods Volunteers participating in the Lake Erie Salmonid Angler Diary Program are encouraged to record information about each personal fishing trip every year. The data are recorded by each diary holder in a standard diary, provided by DEC, according to established methods. Each new volunteer is given written instructions for proper data collection prior to receiving a diary. Anglers are recruited each year through public notification channels (i.e., newspaper columns, letters to sportsman=s groups, hotlines, etc.). Through recruitment, we attempt to maintain a cadre of at least 7 to 75 active anglers each year. The diary program runs through each calendar year. Diaries are intended to represent one full year of fishing activity for each diary holder and are limited to Lake Erie and its tributaries, upstream to the first barrier impassable to fish. Because diaries are not returned until after January each year, there is a oneyear lag in diary summary presentations for the Lake Erie Committee=s annual meeting. Upon receipt, diaries are coded to data sheets and then keypunched onto a spreadsheet for analysis and summation. Once data entry is error-checked, diaries are returned to anglers for their personal use. An overall program summary is provided to each cooperator annually. Also, each cooperator receives a summary of his personal effort and catch for the year. Data represent trout and salmon-directed effort only. Results and Discussion A total of 76 diaries were issued in 27. This was lower than the last five years (which averaged 89) but still a high number compared to the time series. Of these, 42 diarists (55%) reported data fishing specifically for trout and salmon in Lake Erie. A total of 37 anglers reported tributary data while only 7 anglers reported fishing in the open lake. Two anglers reported directed trips in both the open water and tributary components of the fishery. Stream angling, primarily for steelhead, once again dominated the fishery but overall diary effort was reduced despite above average catch rates. Open Lake Waters Seven diarists spent a total of 766 hours on 63 trips targeting trout in Lake Erie in 27 (Table I.1). This was the highest amount of effort spent in the last 5 years by open water diary cooperators despite increasing fuel costs. The average trip consumed 12.2 angler-hours, which was the highest in the time series, and 64 salmonines were caught altogether. On average, anglers caught one fish for every 12 hours of fishing time, which was the fourth poorest ratio in the time series and well above the time series average (1 fish for every 8.8 hours fished). Rainbow/steelhead (rb/sh) continued to be the most caught open water species followed by lake trout and brown trout. A total of 52 rb/sh (81%) were caught, followed by lake trout (9; 14%) and brown trout (3; 5%). No chinook or coho salmon were caught in the open water fishery for the third consecutive year. Average size of the steelhead was 22.8 inches, lake trout 26.2 inches, and brown trout 17.2 inches. Of the 64 fish caught, 51 (8%) of them were harvested. The overall mean catch rate (CPE) was.8 fish/hour, which was similar to the 25 catch rate and well below the series average of.21 fish/hour (Figure I.1). The most trips and catches were from Section I Page 1

37 NYSDEC Lake Erie Annual Report 28 TABLE I.1. Summary of directed trips for salmonids from the OPEN WATERS of New York s portion of Lake Erie reported by angler diary cooperators each year of the program, YEAR # DIARIES ISSUED ANGLERS REPORTING # OF TRIPS TOTAL ANGLER- HOURS AVG. HRS. PER TRIP TOTAL SALMONIDS CAUGHT LT BT RT/SHD CO CH # HOURS TO CATCH LEGAL SALMONID , , , , , Dunkirk with lesser amounts of effort from Barcelona and Sturgeon Point (Table I.2). Tributaries The Lake Erie salmonid tributary fishery remained very good in 27 according to the diary data. A total of 37 anglers recorded 331 trips totaling 1,346 hours of fishing time (Table I.3). This was the lowest number of trips and effort by diary participants since 21. The average trip length was 4.1 hours, which was average for the time series. A total of 1,38 salmonids were caught by diary anglers in 27. The vast majority of the catch (1,24 fish or 98.7%) were rainbow/steelheads. Rb/sh trout have dominated the angler diary program every year, even when significant numbers of other salmonid species (pre-1994) were stocked annually (see Section H, Figure H.1). The size of the angled Section I Page 2 Catch Rate (number/hr) Open Lake Streams FIGURE I.1. Catch rates (# fish/angler hr.) of salmonids for the Open Lake and Stream fisheries reported in Lake Erie angler diaries, TABLE I.2. Trout and salmon catch and effort by OPEN water location on Lake Erie as reported in angler diaries for the 27 calendar year. Catch by Species Water Trips Angler-Hours LT BT RT/STHD CPE Barcelona - Open Lake Barcelona Harbor Cattaraugus - Open Dunkirk - Open Lake Sturgeon Pt. - Open Sturgeon Pt. Harbor TOTAL

38 NYSDEC Lake Erie Annual Report 28 TABLE I.3. Summary of directed trips for salmonids from New York TRIBUTARIES of Lake Erie reported by angler diary cooperators each year of the program, YEAR # DIARIES ISSUED ANGLERS REPORTING # OF TRIPS TOTAL ANGLER- HOURS AVG. HRS. PER TRIP TOTAL SALMONIDS CAUGHT LT BT RT/SHD CO CH # HOURS TO CATCH LEGAL SALMONID , , , , , , , , , , , , , , , , , , , , Catch Rate (number/hr) N = 966 Mean = Size (inches) FIGURE I.2. Length frequency distribution of legal-sized steelhead caught by angler diary cooperators in the New York tributaries of Lake Erie, 27. rb/sh ranged from 7 to 32 inches with an average length of 22.5 inches (Figure I.2). As in the previous two years, steelhead between 22 and 26 inches comprised the bulk of the catch while steelhead abundance over 26 inches dropped dramatically. Catches of brown trout decreased substantially TABLE I.4. Trout and salmon effort and catch from Lake Erie tributaries as reported in angler diaries for the 27 calendar year. Catch by Species Water Trips Angler-Hours BT RT/STHD C CH CPE Chautauqua Creek Canadaway Creek Silver/Walnut Creeks Cattaraugus Creek Eighteen Mile Creek Buffalo/Cayuga/Caz Niagara River Other Streams TOTAL ,24.76 over 26 catches despite continued stocking. Only 14 brown trout were recorded, comprising less than 2% of the total tributary catch. No salmon were reported for the first time in the 24-year time series. Cattaraugus Creek once again dominated the fishing effort in 27 by cooperative diary anglers, accounting for 47% of the trips, 52% of the total effort, and 58% of the catch (Table I.4). CPE was exceptionally high at.85 fish/hour and well above Section I Page 3

39 NYSDEC Lake Erie Annual Report 28 TABLE I.5. Yearly catch rates (fish/hour) and 5 year mean catch rate (22-6) of Lake Erie trout and salmon diary cooperators in major New York tributaries from WATER Year Mean Chautauqua Creek Canadaway Creek Cattaraugus Creek Eighteen Mile Buffalo/Cayuga/ Cazenovia Creeks its 5-year average of.59 fish/hour (Table I.5). Chautauqua Creek, 18 Mile Creek, and Canadaway Creek provided the majority of the remaining catch and effort. Catch rates on Canadaway Creek remained the highest of all the stocked streams (.97 fish/hour). This was the seventh consecutive year that Canadaway Creek had the highest angler catch rates despite relatively poor fishing conditions in the stream in fall 27 due to low water. Catch rates increased over 26 on Chautauqua Creek (.73 fish/hour) but decreased on 18 Mile Creek (.52 fish/hour). Angler usage declined to only 7 trips and 12.6 angler-hours on the Buffalo River system in 27, resulting in only one steelhead caught (.8 fish/hour). Only 5 trips and less than 2 anglerhours were expended on Silver/Walnut Creeks. An increased amount of effort (12.9%) was directed at Other Streams, which are mainly small, non-stocked tributaries, and resulted in a high catch rate of.68 fish/hour. The increased effort in these streams may have been due to the high waters conditions present in many other streams during spring 27. References Markham, J. L. 26. Lake Erie Tributary Creel Survey: Fall 23-Spring 24, Fall 24-Spring 25. Project #: F-48-R-8, Job 111. New York State Department of Environmental Conservation, Albany. 45 pp. Markham, J. L. 28. Lake Erie Tributary Creel Survey: Fall 27-Spring 28. Project #: F-55-R- 1, Job 1. New York State Department of Environmental Conservation, Albany. 23 pp. Overall catch rates were the second highest in the time-series at.76 fish/hour (Figure I.1). More importantly, it continues a trend of high catch rates and stability over the past decade in our Lake Erie tributary fishery. Overall harvest of salmonids caught in the Lake Erie tributaries was 1% in 27, supporting the ongoing trend that many diary tributary fishermen practice strict catch-and-release. These are similar results to tributary creel surveys conducted in 23-4, 24-5 (Markham 26) and 27-8 (Markham 28). Section I Page 4

40 NYSDEC Lake Erie Annual Report 28 J. WILD STEELHEAD ASSESSMENT PROGRAM James L. Markham New York stocks approximately 27, steelhead into its Lake Erie tributaries annually. While stocked fish provide the majority of the recreational opportunity for both lake and stream anglers, there are some streams where successful reproduction and rearing do occur which contribute to the fishery as well. The most notable system is Cattaraugus Creek, where wild steelhead have been present for many years but little was known about their densities and distribution (Mikol 1976). Studies by Mikol (1976) and Goehle (1998) both found about 25% of the adult steelhead in Cattaraugus Creek are naturally produced. Juvenile surveys conducted in some of the better Cattaraugus tributaries confirmed substantial numbers of young-of-year (YOY) rainbow trout present in the fall (Mikol 1976; Goehle 1998; Culligan et al. 22). Subsequent sampling since 21 has focused on other Lake Erie tributaries to assess the potential in each system for producing wild fish. Methods In anticipation of fish passage scheduled for 29 on a series of dams in Chautauqua Creek, a comprehensive survey of the fish community and assessment of juvenile production of steelhead both below and above the two existing fish barriers was conducted in 28. This was the second consecutive year of surveys conducted at these same sites. Two sampling passes were completed at each sampling station using a Smith-Root Model 15-D gasolinepowered backpack electrofishing unit. Blocker seines were not used. Trout were the only fish species collected, but observations on the general abundance (abundant, common, scarce, rare) were made for all non-trout species. All trout were placed into buckets and then transferred into instream flowthrough holding containers until processing. Trout from each run were counted and categorized as young-of-year (YOY) or yearling-and-older (YAO) by size. A maximum of twenty-five YOY and YAO trout from each site were measured for total length. All fish were released after processing. Other data collected at each station included water temperature (F), instream and bank habitat, stream width and site length, clarity, canopy, and substrate composition. Sample populations for all trout were estimated using methods of Seber-LeCren, as described in Everhart and Youngs (1981), for a two pass-through method. Results A total of 2 stations above the dams (Sites 7, 8) and 5 stations below the dams (Sites 1-5) (Figure J.1) were sampled between 18 September and 9 October. An additional station (Site 6) was also sampled on Little Chautauqua Creek (below dam). This stream was previously sampled in 21 and noted for high densities of juvenile steelhead (Culligan et al. 22). Lake Erie Sampling Sites Dams 9 « Chautauqua Creek Westfield Chautauqua Creek Sampling Sites 6 5 Little Chautauqua Creek « Miles FIGURE J.1. Map of the study area on Chautauqua Creek, NY showing locations of sampling sites to determine juvenile steelhead abundance and overall species composition. Sites 1-6 are located below the dams while sites 7-8 are above. Section J Page 1

41 NYSDEC Lake Erie Annual Report 28 Sites Below Dam Juvenile steelhead were collected at every sampling site below the dams (Table J.1). Densities of youngof-year (YOY) steelhead ranged from 4 fish/acre at the lowermost site (Site 1) to 1,596 fish/acre just below the dams (Site 5). Similar to last year, densities of YOY steelhead were highest just below the dams and decreased downstream. Average densities of YOY steelhead between all sites were essentially equal between sampling years (86 fish/acre in 27; 794 fish/acre in 28). Yearling and older (YAO) steelhead densities ranged from 14 fish/acre at Site 6 in Little Chautauqua Creek to 5 fish/acre at Site 5. Average densities of YAO steelhead were only one third the abundance in 28 (33 fish/acre) compared to 27 (94 fish/acre), possibly due to the lower water conditions in Fall 27. TABLE J.1. List of sampling sites, number of young-of-year (YOY) and yearling and older (YAO) rainbow trout sampled, area sampled, and density (trout/acre) on Chautauqua Creek in Fall 28. The density of trout found in 27 is also listed for comparison. Site Pass 1 Pass 2 Area Sampled (acre) Density (trout/acre) 27 Density (trout/acre) YOY YAO YOY YAO YOY YAO YOY YAO , ,6 34 1, , , Fifteen non-trout species were also sampled at the six sites below the dam (Table J.2). The overall fish community was similar to 27. Longnose dace, blacknose dace, mottled sculpins, and rainbow darters were found at every site while white suckers were only found at the lowermost sampling site. Juvenile smallmouth bass were found at the two lowermost sampling sites and had abundances of 264 and 38 fish/acre at Sites 1 and 2, respectively. TABLE J.2. Relative abundance of non-trout species sampled by site in Chautauqua Creek in Fall 27. Abundance codes: A=abundant; C=common; S=scarce; R=rare. Species Site 1 Site 2 Site 3 Site 4 Site 5 Site 6 Site 7 Site 8 Smallmouth bass A A Longnose Dace A A A A A C C C Blacknose Dace R R A A A C C A Central Stoneroller A C R S S Creek Chub R S C C S S River Chub C C S S Rainbow Darter A A C C A R C C Mottled Sculpin S S C C C A C A Northern Hogsucker A A R C S C S White Sucker C Bluntnose Minnow S C Pumpkinseed R R Bluegill R Redfish Shiner R Fathead Minnow C Largemouth Bass R Sites Above Dam Juvenile rainbow trout, presumed to be steelhead, were sampled only at the lowermost sampling site (Site 7) above the dams (Table J.1). A few juvenile and YAO brown trout were found in the upper sampling station (Site 8), but no steelhead. Densities of steelhead were 429 and 37 fish/acre at Site 7 for YOY and YAO, respectively. This was higher YOY abundance than 27 (63 fish/acre) at this site but lower YAO abundance (174 fish/acre). Overall abundances for both YOY and YAO were lower than 27. Eight different non-trout species were found above the dams (Table J.2). Species composition was similar to 27 except for the occurrence of bluntnose minnows and one largemouth bass. Longnose and blacknose dace, rainbow darters, and mottled sculpins were the most commonly caught species. Central stonerollers, found in 27, were not observed in 28. Discussion The second year of pre-fish passage sampling on Chautauqua Creek confirmed the impact of the dams on the steelhead population and overall fish community. Very low water conditions during the summer and fall 27 inhibited fish passage above the dams to the upper areas of the watershed during the fall 27 steelhead run. Abundances of YOY steelhead below the dams were almost four times Section J Page 2

42 NYSDEC Lake Erie Annual Report 28 higher than abundances above the dams in 28. Compared to 27, abundances of YOY steelhead above the dams were 39% lower and YAO 81% lower in 28. This suggests that passage of steelhead over the dams is prohibited during very low water conditions. Similar to last year, stream composition of non-trout species also appears to be affected by the dams with several fish species present below the dams and not above. gairdneri) of the upper Niagara River and tributaries of eastern Lake Erie. MS Thesis. SUNY at Buffalo. 157 pp. Seelbach, P. W Population biology of steelhead in a stable-flow, low-gradient tributary of Lake Michigan. Transactions of the American Fisheries Society 122: Despite less than ideal water conditions, the abundance of YOY steelhead in Chautauqua Creek were comparable to fall densities found in higher quality Michigan streams (Seelback 1993; Godby et al. 27). However, densities were lower than Spooner Creek (3,245 fish/acre), which is considered the top steelhead producing stream in New York s Lake Erie watershed (Culligan et al. 22). Nearly identical abundances of YOY steelhead below the dams in both sampling years suggest that this area is at its carrying capacity. Further studies need to be conducted to determine if this production is contributing to the adult steelhead population of this stream. References Culligan, W. J., D. W. Einhouse, J. L. Markham, D. L. Zeller, R. C. Zimar, and B. J. Beckwith. 22. NYSDEC Lake Erie 21 Annual Report to the Lake Erie Committee. New York Department of Environmental Conservation, Albany. Everhart, W. H. and W. D. Youngs Principles of Fishery Science. Cornell University Press, Ithaca, NY. 349pp. Godby, N. A. Jr., E. S. Rutherford, and D. M. Mason. 27. Diet, feeding rate, growth, mortality, and production of juvenile steelhead in a Lake Michigan tributary. North American Journal of Fisheries Management 27: Goehle, M. A Assessment of natural recruitment in the mixed rainbow/steelhead fishery of Cattaraugus Creek and tributaries. MS Thesis. SUNY at Buffalo. 45 pp. Mikol, G. F Investigation of population dynamics of the lake-run rainbow trout (Salmo Section J Page 3

43 NYSDEC Lake Erie Annual Report 28 Introduction Beginning in 1993, a midsummer east basin fisheries acoustic survey was implemented to provide a more comprehensive evaluation of the distribution and abundance of rainbow smelt. This initiative has been pursued under the auspices of the Lake Erie Committee's Forage Task Group (FTG), and is a collaboration of neighboring east basin Lake Erie jurisdictions and Cornell University's Warmwater Fisheries Unit through coordinated management efforts facilitated by the Great Lakes Fishery Commission (GLFC). Some of the recent progress in the development an acoustic survey program was achieved when Lake Erie s FTG was awarded a grant to purchase a modern signal processing and data management system for acoustic surveys on Lake Erie (Einhouse and Witzel 23). The new data processing system arrived in 22. In 23, Lake Erie representatives from New York State Department of Environmental Conservation and the Ontario Ministry of Natural Resources also attended a workshop to attain proficiency in this new software. The newly trained biologists then hosted a second workshop to introduce this system to the Lake Erie FTG. During 25 FTG members upgraded Lake Erie acoustic hardware system by the purchase of a Simrad EY6 GPT/transducer. Finally, in 28, several members Lake Erie s FTG participated in a Great Lakes Acoustic Workshop devoted to implementation of Standard Operating Procedures (SOP). Completion of this workshop was a benchmark event for then proceeding to re-processing an acoustic data series beginning in 1997 and applying new standards. K. FISHERIES ACOUSTIC SURVEY 1 Donald W. Einhouse and Larry Witzel 2 Section K Page 1 Survey Methods A thorough description of survey methodology as well as a thorough description of the entire series of acoustic survey results for the eastern basin Lake Erie is being pursued as a separate report expected to be available during 29. In general, standard survey procedures have been in-place for offshore transect sampling of eastern Lake Erie since This midsummer, nighttime survey is implemented as an interagency program involving multiple vessels to collect acoustic signals of pelagic fish density and distribution, with an accompanying midwater trawling effort to characterize species composition. The 28 Survey In recent years, New York s annual contribution to the east basin survey is mid-water trawling by the RV Argo to document fish species composition. Fish densities and distribution are measured by a scientific echosounder aboard the Ontario Ministry of Natural Resources (OMNR) research vessel, RV Erie Explorer. Acoustic data acquisition for the 28 survey was completed without incident and attained the full compliment of twelve acoustic transects totaling 186 nautical miles and 764, KB of raw acoustic data (Figure K.1). However, mid-water trawl collections and temperature profiles in 28 were abbreviated due to mechanical difficulties on the RV Argo. In all, both acoustic survey vessels combined for 32 temperature profiles, and the RV Argo made 9 mid-water trawl tows during a shortened 28 mid-water trawling program. 1- This is partially a re-print of the east basin acoustic section described in the 28 Lake Erie Forage Task Group Report 2- Larry Witzel s affiliation is Ontario Ministry of Natural Resources, Lake Erie Management Unit

44 NYSDEC Lake Erie Annual Report 28 At this writing the acoustic data series from 1999 to 23 has been re-processed and analyzed using our new survey standards. This renewed data analysis effort is now briefly suspended to address other pressing report deadlines, but will resume during April, 29. The five years of completed analysis of acoustic survey results using the new SOP (1999 to 23) describe trends in densities of pelagic forage fish and these new measures are shown in Table K.1, along with a series of independent bottom trawl measures of yearling-and-older (YAO) rainbow smelt. Figure K.1. July 28 eastern basin Lake Erie acoustic survey transects, mid-water trawl and temperature profile sites visited by the RV Erie Explorer and RV Argo. Acoustic Series Results Procedures for the east basin acoustic survey have now been completed largely through the support of GLFC sponsored project Study group on fisheries acoustics in the Great Lakes. At this time the principal investigators for Lake Erie s east basin survey are incorporating the new SOP for each survey year, and then recomputing fish densities based on these new standards. Among these standard data processing elements is the use of filters (N v ) for computing fish abundance in densely concentrated areas to diminish possible bias associated with extrapolating abundance based on mean in-situ target strength (Rudstam et al. 23). Additionally, a standard objective method has now been developed to ascribe passive noise thresholds for each survey transect. A complete description of our data collection and processing methods will be forthcoming in a separate document with accompanying results for the entire time series of this acoustic survey. Table K.1. A comparison of bottom trawl indices of Yearlingand-older (YAO) rainbow smelt with acoustic indices of YAO pelagic forage fish during July, 1999 to 23. Number per hectare Sampling Method East Basin Stratum Btm. Trawl YAO Smelt ON-DW Btm. Trawl YAO Smelt NY-Fa Btm. Trawl YAO Smelt PA-Fa Btm. Trawl YAO Smelt juris. trwl ave. (area wgt.) Acoustic YAO Fish East Basin Acoustic (YAO) 8,425 6,115 9,414 1,93 5,26 From 1999 to 23 the independent bottom trawl surveys by eastern basin jurisdictions described in Lake Erie s FTG report (FTG 28) found a characteristic alternate year abundance cycle for yearling-and-older (YAO) rainbow smelt. A similar alternate year abundance pattern was also apparent in acoustic densities of YAO pelagic forage fish during this period (Table K.1). This synchrony of year-to-year abundance fluctuations observed for acoustic densities and independent bottom trawl abundance measures for the dominant pelagic forage species (rainbow smelt) in eastern Lake Erie lend support to the veracity of the newly developed acoustic survey estimation techniques for pelagic forage fish. We expect to resume analysis of acoustic results for years 1997, 1998, and 24 through 28 during spring 29. The entire 1997 to 28 Section K Page 2

45 NYSDEC Lake Erie Annual Report 28 data series is expected to be thoroughly reported in a separate document with an accompanying description of survey methods and data processing procedures. Upon completion of this overview document, subsequent results will be updated annually in Lake Erie s FTG Report. Discussion The interagency fisheries acoustic survey of eastern Lake Erie has proven to be a highly successful, collaborative effort for rainbow smelt assessment between fisheries agencies in the Province of Ontario, New York and Pennsylvania. This ongoing program has also successfully partnered with academic researchers through the GLFC and addressed some previously unmet needs for the Lake Erie fisheries management community. This interagency acoustic partnership in forage fish assessment began in Lake Erie s east basin, and has more recently expanded into central and western basins using the eastern Lake Erie program as a model. Finally, acoustic survey applications are expanding further as a fishery assessment tool in Lake Erie to include such endeavors as habitat mapping. As such, continued support will be required to efficiently administer acoustic surveys. Lake Erie s acoustic hardware and software are broadly shared among the five jurisdictions represented on the FTG. This inter-agency acoustic monitoring program will require a dedicated ongoing effort for maintenance, upgrades, expansion of site licenses, and periodic training of personnel to remain as a functional fish stock assessment tool. The GLFC and the Lake Erie Committee have demonstrated strong support for acoustic survey efforts on Lake Erie, and the biologists responsible for these surveys are very grateful for these efforts. Some FTG representatives participated as core members of a Great Lakes acoustic study group charged with developing standards for fishery acoustic surveys in the Great Lakes. One of the principal accomplishments of the Acoustic Study Group was development of Great Lakes SOP document, with an accompanying SOP workshop, delivered in 28. The ongoing, eastern basin Lake Erie acoustic survey represents an excellent example of a standard, inter-agency assessment of the pelagic forage fish community conducted in the Great Lakes. Lake Erie s acoustic survey has benefited from collaboration with experts from beyond our borders. Individuals leading Lake Erie s acoustic program are actively engaged in updating survey results for the entire data series and are targeting a comprehensive summary to be prepared as a separate report. Section K Page 3

46 NYSDEC Lake Erie Annual Report 28 References Einhouse, D. W. and L. D. Witzel, 23. A new signal processing system for Inter-agency fisheries acoustic surveys in Lake Erie. Great Lakes Fishery Commission Completion Report, December, 23. Rudstam, S. L., S. L. Parker, D. W. Einhouse, L. D. Witzel, D. M. Warner, J. L. Stritzel, D. L. Parrish, and P. J. Sullivan. 23. Application of in situ target strength estimations in lakes: examples from rainbow-smelt surveys in Lakes Erie and Champlain. ICES Journal of Marine Science, 6: Section K Page 4

47 NYSDEC Lake Erie Annual Report 28 L. WALLEYE DIET STUDY Donald W. Einhouse Introduction A component of forage fish investigations at the Lake Erie Unit includes ongoing predator diet analysis. Beginning in 1993 we have annually examined angler-caught adult walleye at fish cleaning stations for dual objectives of 1) characterizing walleye diet and 2) estimating the age distribution of the sport harvest. Information describing the age distribution of the sport harvest is contributed to the Lake Erie Committee s Walleye Task Group for catch-at-age analysis population estimation. The 16-year series of walleye diet data collected from this same effort are presented here as a component of Lake Erie forage assessment. Results The annual sample of walleye for this diet investigation varied widely from a high of 339 in 2 to a low of 34 in 24. The number of sampled stomachs with food ranged from 127 in 1995 to only 9 in 24. Figure L.1 shows that through most of the 1993 to 28 time series, rainbow smelt represented the majority of the summertime adult walleye diet encountered by anglers. 1% Angler Caught Walleye Diet Components smelt all other fish invertebrates Methods From 1993 to 28, intermittent, summertime (June- August) visits were made to fish cleaning stations to gather stomach content information from angler caught walleye. Occasionally, the data collection efforts at municipal fish cleaning stations were augmented by a NYS DEC fish cleaning service provided adjacent to launch ramps. Periodic NYS DEC fish cleaning services provided an additional incentive for walleye anglers to contribute information for this investigation. Data collected at fish cleaning locations included the location of capture, walleye total length, sagittal otoliths for age determination, walleye sex and stage of maturity, and number and volume of readily identifiable prey taxa volumes measured to the nearest milliliter. The effort devoted to this program and samples obtained has varied widely among years due to fluctuating walleye fishing quality, and uneven availability of staff to conduct this effort. During 28 we examined 146 walleye stomachs, 63 contained food remains, and 47 of these stomachs had food items identifiable to genus or species. Section L Page 1 percent of stomach volume 8% 6% 4% 2% % Figure L.1.The percent contribution (by volume) of identifiable prey in stomachs of adult walleye caught by summertime anglers in New York s portion of Lake Erie, 1993 to 28. Infrequent occurrences of invertebrates in stomachs were largely mayfly nymphs (Hexagenia spp.) found in June and early-july samples some years. The 21 collections were the first occasion that prey fish other than rainbow smelt made a notable contribution to the diet. From 21 to 23 most of the observed prey fish taxa other than smelt were clupeid species and emerald shiners. During both 26 and 27 at least five fish species were identified in walleye stomachs. In 28 samples the contribution by volume of identifiable species included rainbow smelt (96 %), Morone spp. (white perch/white bass) (3 %), and round goby (1 %).

48 NYSDEC Lake Erie Annual Report 28 Discussion Ongoing summertime adult walleye diet investigations continued to find smelt as the most abundant prey in adult walleye stomachs. However, collections in 26 and 27 were especially noteworthy because several other prey fish species contributed measurably to walleye diets. Increased prey species diversity coupled with lower smelt abundance is a consistent observation between independent walleye diet and forage fish trawling programs (Section M) in these years. In 28 diet diversity declined, and was more similar to observations in the 199 s when rainbow smelt dominated the diet. We expect this summertime walleye diet series collected from fish cleaning stations to be useful in furthering our understanding of factors contributing to walleye fishing quality in eastern Lake Erie. These collections also represent the longest continuous data series to describe the summertime diet of adult walleye found among any eastern Lake Erie jurisdiction. As such, these collections will be maintained as an ongoing program of NYS DEC s Lake Erie Unit. Section L Page 2

49 NYSDEC Lake Erie Annual Report 28 M. FORAGE TRAWL SURVEY Donald W. Einhouse Introduction Annual bottom trawling to characterize the forage fish community has been underway since This survey has an additional objective of assessing the status of yellow perch and those results are described in Section C of this report. New York s annual forage fish abundance measures are also merged with broader lake wide assessments of forage fish populations and reported with the interagency Forage Task Group (FTG 28). catch-per-hectare 7,. 6,. 5,. 4,. 3,. 2,. 1,. - Forage Fish Abundance Trends spiny-rayed soft-rayed clupeid Methods This fall trawling series was initiated in 1992 and replaced the Juvenile Percid Assessment conducted from 1986 to 1991 (Culligan et al. 1992). The current trawling program is conducted during October at randomly selected stations between the 5- and 1-ft depth contours in New York s portion of Lake Erie. Standard tow duration is 1 minutes. Additional detail for trawl specifications can be found in Section C of this report. Survey procedures generally follow those performed for an interagency, western basin Lake Erie assessment that is reported annually in Lake Erie s Forage Task Group Report (FTG 28). Results Each year, the principal functional group among forage fishes in the New York waters of Lake Erie is soft-rayed species (Figure M.1). Figure M.1 Catch-per-hectare (2.471 acres) of functional groups of forage fishes collected with a standard trawl from approx. 3 sites in the New York waters of Lake Erie, October, 1992 to 28. This soft-rayed forage fish group is typically dominated by rainbow smelt. From the inception of this trawling program in 1992 through 2, an alternate year cycle of expanded yearling smelt abundance has been a predictable characteristic of annual forage abundance (Figure M.2). trawl catch per hectare 3, 2,5 2, 1,5 1, age-1-and-older smelt abundance Figure M.2. Catch-per-hectare (2.471 acres) of yearling-andolder rainbow smelt collected with a bottom trawl from approximately 3 sites between the 5 and 1 ft depth contours in the New York waters of Lake Erie, October, 1992 to 28. Section M Page 1

50 NYSDEC Lake Erie Annual Report 28 Through these earlier years of trawling, in the absence of an abundant yearling cohort of smelt, young-of-the-year (YOY) smelt typically were the most abundant forage fish component. Beginning in 21 several other species also began to make significant contributions to this soft-rayed segment of the forage fish community, including emerald shiners, trout-perch and round gobies. From year 2 through 23 yearling-and-older (YAO) smelt abundance remained at lower abundance, along with their predictable alternate-year abundance cycle. During 24 YAO smelt briefly re-emerged as a very abundant forage fish component in this trawling survey then subsided to lower abundances in 25 and thereafter. Round goby emerged in the late 199's as a new species among this soft-rayed forage fish group and their abundance has generally increased in the ensuing survey years. In 27 round goby were encountered at peak abundance, followed most recently by a sharp decline observed in 28 (Figure M.3). trawl catch per hectare 1,4 1,2 1, round goby abundance Figure M.3. Catch-per-hectare (2.471 acres) of all life stages of round goby collected with a bottom trawl from approximately 3 sites between the 5 and 1 ft depth contours in the New York waters of Lake Erie, October, 1992 to 28. Beginning in 21 emerald shiners also became a predictable annual contributor to forage biomass and abundance. However, in 27 and 28 emerald shiner abundance declined sharply from the peak measure observed in 26 (Figure M.4) trawl catch per hectare 1,8 1, emerald shiner abundance Figure M.4. Catch-per-hectare (2.471 acres) of all life stages of emerald shiners collected with a bottom trawl from approximately 3 sites between the 5 and 1 ft depth contours in the New York waters of Lake Erie, October, 1992 to 28. Despite high variability in annual measures of individual species, overall forage fish abundance and diversity in 28 remained at high levels relative to the entire time series. In addition, the 28 survey found the spiny-rayed forage fish component with its largest contribution, to date, to overall forage abundance. This spiny-rayed component was comprised mostly of age- yellow perch and age- white perch. 2 Discussion Bottom trawling suggests that autumn forage fish densities in the New York waters of Lake Erie during 28 were high relative to the history ( ) of this program. In past years, large annual fluctuations in forage fish abundance observed in both acoustic and bottom trawl assessments have been attributed to an alternate-year cycle in rainbow smelt abundance. In 24 high densities of yearling smelt briefly emerged following four years of relatively low abundance, and then subsided in 25 and thereafter. Nevertheless, the most abundant species contributing to the 28 forage fish index was rainbow smelt despite their relative declines in recent years. Much of this smelt contribution was by the YOY cohort which was numerically very abundant but otherwise did not contribute measurably to the mass of our forage fish collections. The largest contribution to the weight of our 28 samples was by age- yellow perch, Section M Page 2

51 NYSDEC Lake Erie Annual Report 28 then by trout-perch. However, yellow perch have been generally uncommon in predator diets, and trout-perch almost never appear in stomach sampling of piscivorous fish. References Culligan, W. J., F. C. Cornelius, D. W. Einhouse, D. L. Zeller, and R. C. Zimar Annual Report to the Lake Erie Committee. New York Department of Environmental Conservation, Albany. 52 pp. FTG 28. Report of the Lake Erie Forage Task Group. Presented to the Standing Technical Committee, Lake Erie Committee, Great Lakes Fishery Commission. Section M Page 3

52 NYSDEC Lake Erie Annual Report 28 N. OPEN LAKE SPORT FISHING SURVEY Donald W. Einhouse Introduction Since 1988, a direct contact sport fishing survey has been conducted to monitor boat fishing activity. This has been a standard, annual program that extended from May through October along the entire New York portion of Lake Erie. From 1993 to 1997 this survey was augmented by a spring creel survey of the nighttime walleye fishery, and those results were reported annually in earlier editions of this report. This nighttime survey component was suspended from 1998 to 25, and then resumed in 26 to update the status of this fishery. This spring, nighttime walleye fishery survey is now planned to proceed at 3-year intervals. Annual creel surveys in 22 and thereafter employed a different creel survey methodology than had been our standard for the previous 14 years. The departure from our previous standard was necessary due to a new constraint in administering the annual aerial survey contract. Current policies preclude efficient implementation of our previous aerial survey contract to obtain angler counts for the entire survey period. Instead, an alternative new creel survey approach was adopted in 22 and continued thereafter that measures fishing activity from the five major harbors bordering New York s portion of Lake Erie. We continued a limited number of aerial counts from 22 to 24 to evaluate whether our change in survey methods had any bearing on absolute measures of fishing effort and harvest. A separate report (Einhouse 25) has been completed that compares old and new survey standards for Lake Erie and thoroughly documents procedures through our history of creel surveys. Survey Procedures Methods Standard survey methods from 1988 to 21 were patterned after a study by Schmidt (1975). Schmidt s approach collects effort and catch information as independent samples with two collection schedules of stratified random sampling. Aerial counts of fishing boats were conducted to measure daytime fishing effort. Catch and harvest data were obtained by roving between five to six representative fishing access sites to conduct interviews of boat anglers who had just completed their fishing trip. Angler interviews were conducted between 9 EDT and 1 hour after sunset. During 1991, and for all surveys after 21, a new standard methodology was adopted due to an administrative constraint for securing an aerial survey contract in a timely fashion to monitor angling effort. Our current method to estimate fishing effort is an access approach described by Pollock et al. (1994). The specific procedures for this access method of creel design as applied to the New York waters of Lake Erie are described in a separate report (Einhouse 25). The sampling period to assess the daytime open lake sport fishery occurs from May through October each year. Data collection for our current methodology is now stratified by day type (weekday-weekend day), harbor, and month. Section N Page 1

53 NYSDEC Lake Erie Annual Report 28 Data Analysis Daytime creel survey estimates for fishing effort, harvest, and catch rates, with associated precision (standard error) measures, were calculated for each stratum using the formulae described in Einhouse 25. Survey Results Beginning in 22 all estimates of fishing effort, catch, and harvest were based on a different creel survey methodology than was employed for the previous 14 years of the survey. Nevertheless, some independent measures of fishing activity suggest our results remain directly comparable for the entire 1988 to 28 time series (Einhouse 25). Overall 28 open water sport fishing effort in New York waters of Lake Erie was estimated as 314,432 angler-hours. Peak fishing activity occurred during July and the most frequently used site was the Buffalo Small Boat Harbor (Table N.1). TABLE N.1 Distribution of 28 open water boat fishing effort for walleye in New York s portion of Lake Erie. Distribution of Boat Fishing Effort (angler-hours) Harbor May Jun Jul Aug Sep Oct Total Barcelona 2,65 17,377 12,645 15,669 5,47 2,99 55,865 Dunkirk 4,774 14,47 21,366 21,666 11, ,798 Cattaraugus 3,16 12,473 15,4 13,693 7,243 7,725 59,28 Sturgeon Pt. 3,178 6,887 9,465 8,677 7,385 1,753 37,346 Small Boat Harbor 8,854 26,261 25,58 13,61 11,3 3,6 88,143 Total angler-hrs (2 std err.) 22,517 77,45 83,575 73,315 42,664 15, ,432 (4,668) The 28 fishing effort estimate was the third lowest annual total of the 21-year time series but increased for the second consecutive year (Figure N.1). millions of angler-hours Overall Boat Fishing Effort walleye bass all others Figure N.1. Open water sport fishing effort in New York waters of Lake Erie by walleye anglers, bass anglers, and all others, May- October, During the 28 fishing season, walleye angling was the largest component of the boat fishery with 5 percent of the overall angling effort. Smallmouth bass angling ranked second in boat fishing effort with 27 percent of the total. Among the remaining effort, anglers fishing for yellow perch contributed 11 percent of the overall effort, and anglers fishing for anything accounted for another 9 percent of the total in 28. The remaining 3 percent of the fishing effort total was distributed mostly among trout specialists, and Ecosid specialists returning to the Buffalo Small Boat Harbor (Figure N.2). other spp. 3% anything 9% y. perch 11% Distribution of Boat Fishing Effort black bass 27% walleye 5% black bass walleye y. perch anything other spp. Figure N.2 Distribution of directed sport fishing effort by boat anglers in New York waters of Lake Erie, May-October, Section N Page 2

54 NYSDEC Lake Erie Annual Report 28 In 28 the total estimated daytime walleye harvest was 29,17 fish (Table N.2). This ranked the 28 walleye harvest very similar to the 27 estimate, and near the median value for this 21-year survey series. TABLE N.2 Harvest of selected species by boat anglers fishing on the New York waters of Lake Erie, May-October, SPECIES CAUGHT (Conf.Limits)* HARVESTED (Conf.Limits)* yellow perch 69,32 31% 54,274 33% walleye 32,377 19% 29,17 2% smallmouth bass 89,123 23% 6,89 31% white bass & perch 18,839 22% 1,28 58% rainbow trout 1,68 35% % rock bass 4,21 37% % lake trout % 18 69% all other species** 47,124 12,576 TABLE N.3. Distribution of daytime walleye catch and harvest totals in the New York waters of Lake Erie during walleye catch and harvest distribution May Jun Jul Aug Sep Oct Total Barcelona catch - 3,9 1,621 2, ,24 harvest - 2,872 1,554 2, ,517 Dunkirk catch ,91 3,422 1,128-1,47 harvest ,424 2,83 1,128-9,1 Cattaraugus catch 19 1,282 2,282 2, ,124 harvest 19 1,282 2,97 2, ,78 Sturgeon catch ,19 harvest ,722 Buffalo catch 7 1,562 3, ,712 harvest 28 1,313 2, ,998 Total catch 181 7,182 12,749 9,836 2, ,377 harvest 128 6,372 11,79 8,541 2, ,17 The 28 walleye fishing effort accompanying this walleye harvest increased 16 percent from 27, but remained among the lower effort totals measured in this same 21-year survey series. Walleye fishing effort the last four years has been somewhat elevated from the low ebb measured in 24, but remains approximately half of the average annual walleye fishing effort measured over the entire survey series (Figure N.3). Walleye Targeted Effort and Harvest Trends The spatial distribution of the 28 walleye harvest is shown in Figure N.4. Most of the harvest occurred in waters adjacent to Chautauqua County, and the area between Dunkirk Harbor and the mouth of Cattaraugus Creek produced the highest harvest in 28. effort (x1, hrs) effort (1,'s of hrs) harvest , 12, 6, number harvested Figure N.3 Annual trends in walleye sport fishing effort (anglerhours) and number harvested from May through October 1988 to 28. The 28 New York walleye sport fishery peaked during July, but the June through August period contributed 92 percent of the total harvest estimate. Dunkirk, Barcelona and Cattaraugus Creek Harbor survey locations accounted for 77 percent of the walleye harvest total. Figure N.4. Annual harvest of walleye by 1 minute geodetic grid on the New York waters of Lake Erie during 28. The overall targeted walleye catch rate during the 28 fishing season was.18 fish per hour, which was the 6 th highest measure observed in this 21-year data series. The average total length of harvested Section N Page 3