Assessment of Sport Fish Distribution and Relative Abundance in the Lower Red Deer River, Alberta, Phase II

Transcription

1 Assessment of Sport Fish Distribution and Relative Abundance in the Lower Red Deer River, Alberta, Phase II CONSERVATION REPORT SERIES

2 The Alberta Conservation Association is a Delegated Administrative Organization under Alberta s Wildlife Act. CONSERVATION REPORT SERIES 25% Post Consumer Fibre When separated, both the binding and paper in this document are recyclable

3 Assessment of Sport Fish Distribution and Relative Abundance in the Lower Red Deer River, Alberta, Phase II Jason Blackburn and Jason Cooper Alberta Conservation Association 2 nd Floor, YPM Place 53 8 Street S. Lethbridge, Alberta T1J 2J8

4 Report Series Co editors PETER AKU KELLEY KISSNER Alberta Conservation Association 5 Tuscany Meadows Crescent NW #11, 9 Chippewa Rd Calgary, Alberta T3L 2T9 Sherwood Park AB T8A 6J7 Conservation Report Series Type Data, Technical ISBN printed: ISBN online: Publication No.: T/195 Disclaimer: This document is an independent report prepared by the Alberta Conservation Association. The authors are solely responsible for the interpretations of data and statements made within this report. Reproduction and Availability: This report and its contents may be reproduced in whole, or in part, provided that this title page is included with such reproduction and/or appropriate acknowledgements are provided to the authors and sponsors of this project. Suggested citation: Blackburn, J., and J. Cooper. 26. Assessment of sport fish distribution and relative abundance in the Lower Red Deer River, Alberta, Phase II. Technical report, T 26 3 produced by Alberta Conservation Association, Lethbridge, Alberta, Canada. 56 pp + App. Cover photo credit: David Fairless Digital copies of conservation reports can be obtained from: Alberta Conservation Association #11, 9 Chippewa Rd Sherwood Park AB T8A 6J7 Toll Free: Tel: (78) Fax: (78) info@ab conservation.com Website: conservation.com i

5 EXECUTIVE SUMMARY Fish species distribution and abundance was assessed on 45 km of the Lower Red Deer River (LRDR) using electrofishing. A total of 9 1 km reaches were sampled of a predetermined 95 sample reaches. Species distribution and abundance, and total abundance by section, were determined from capture totals, visual counts, and catchper unit effort (CPUE). Goldeye and shorthead redhorse displayed the broadest distributions, as well as the greatest abundance throughout the study area. Sauger was the next most abundant and widely distributed sport fish species, followed by walleye, burbot, mooneye, and northern pike. Sections with the highest total abundance of fish were section 1 near Joffre, downstream of the Highway 11 bridge crossing, and sections 12 to 13 near Buffalo and Bindloss, toward the confluence with the South Saskatchewan River near the Alberta Saskatchewan border. The total number of fish observed during sampling differed substantially from the total number captured, with 1,116 fish observed compared with only 429 captured. Capture success was low (inefficient) and possibly linked to water turbidity, with reduced success in clear water. Overall sample efficiency was highest via visual counts in clear water, with 58% of all tallied fish made by visual counts in three resampled sections. Comparison of abundance data collected in 24 with that collected between revealed a statistically significant decline in total relative fish abundance from an average of 25.5 fish/km in to 5.3 fish/km in 24. In particular, significant decreases in abundance were observed for goldeye, sauger, walleye, white sucker, shorthead redhorse, longnose sucker, and quillback sucker. There was no significant change in relative abundance of burbot, mountain whitefish, northern pike, lake whitefish or lake sturgeon. Declines in abundance were attributed to sampling inefficiency in 24 and/or the effects of consecutive drought years prior to the assessment. Species composition between assessments was similar; however, species distribution patterns were typically smaller and more fragmented in 24. Species richness was greater in 24 than the previous survey and was probably the result of a larger study area and greater sampling effort. In comparison to the assessment in , aging structures collected in 24 indicated slower growth rates in goldeye and mooneye, but faster rates for walleye and sauger. Use of a broader variety of sampling methods is recommended to increase capture success, and an angler creel survey could be used to verify anecdotal reports of increased sauger catches in recent years. A comprehensive habitat assessment of the ii

6 LRDR should be conducted to assist future conservation measures to ensure sustainability of the fishery. Additional focused sampling of the data deficient species quillback and sauger should be undertaken, encompassing other southern Alberta river systems to ensure sufficient data capture. Long term monitoring of declining sauger and goldeye populations should also be initiated. iii

7 ACKNOWLEDGMENTS This study was funded by the Alberta Conservation Association (ACA). Thanks to Kevin Wingert and Vance Buchwald (ASRD, Fish and Wildlife, Fisheries Biologists, Red Deer) and Cam Wallman (ASRD, Fish and Wildlife, Fisheries Biologist, Brooks) for their time and expertise piloting the boat and sampling during the field portion of the assessment. Special thanks to Byron Jensen (ASRD, Fish and Wildlife, District Conservation Officer, Drumheller) for offering his knowledge of the LRDR and for filling in and working long hours on the river on a Sunday when we were shorthanded. Additional thanks to Chad Tourand for providing accommodations and entertainment during equipment down time and repair. This report benefited from constructive comments offered by Cam Wallman, Glen Clements (ASRD, Fish and Wildlife, Fisheries Biologist, Lethbridge), Vance Buchwald and Trevor Council (ACA, Fisheries Biologist). iv

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9 TABLE OF CONTENTS EXECUTIVE SUMMARY...ii ACKNOWLEDGMENTS...iv TABLE OF CONTENTS...v LIST OF FIGURES...vi LIST OF TABLES... vii LIST OF APPENDICES... viii 1. INTRODUCTION Phase II objectives STUDY AREA MATERIALS AND METHODS Phase I Phase II RESULTS Species composition and relative abundance Species distributions Fish catchability Sport fish species distribution and habitat observations Non sport fish species distributions Comparison of 24 and data DISCUSSION Capture success in the 24 assessment Methodology Measuring total fish abundance and distribution Comparing relative abundances Comparing species distributions Potential effects of angling Future considerations and recommendations LITERATURE CITED APPENDICES...57 v

10 LIST OF FIGURES Figure 1. Map of the Red Deer River watershed showing the 473 km study section...4 Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Catch per unit effort by species during the initial sampling event using electrofishing on the Lower Red Deer River in Observed total number of fish by species from all sampling events on the Lower Red Deer River in Combined observed and captured fish totals by species from all sampling events on the Lower Red Deer River in Total catch per unit effort by river kilometer on the Lower Red Deer River in Combined observed and captured fish tallies per river kilometer during the initial spring sampling event on the Lower Red Deer River in Observed versus captured fish abundance per section on the Lower Red Deer River in Comparison of combined observed and captured fish totals during initial spring conditions with observed totals from clear water resampling on the Lower Red Deer River in Comparison of capture results for sport fish species between assessments in and 24 on the Lower Red Deer River...29 Figure 1. Comparison of capture results of fish species between assessments in and 24 (initial sampling event) on the Lower Red Deer River...29 Figure 11. Fish species presence by section in the Lower Red Deer River, and Figure 12. Combined observed and capture totals per sample kilometer, and Figure 13. Mean June discharge and percent fish recruitment from the 24 total fish sample Figure 14. Mean June discharge and percent fish recruitment from the total fish sample...48 vi

11 LIST OF TABLES Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Fish species captured during the Lower Red Deer River sport fish assessment in Summary of measurements and species abundance for fish species in the Lower Red Deer River assessment in Species capture totals by section during the initial spring sampling event on the Lower Red Deer River in Observed species totals by section during the initial spring sampling event on the Lower Red Deer River in Combined captured and observed species totals by section for the initial spring sampling event on the Lower Red Deer River in Combined captured and observed species totals during resampling of sections on the Lower Red Deer River in Combined captured, observed and catchability totals by species from all sampling events on the Lower Red Deer River in Comparison of fish species totals and percent composition between assessments in and 24 on the Lower Red Deer River using data from sites common to both assessments...3 A comparison of fish abundance between sites sampled in and 24 assessments...31 Table 1. Comparison of sport fish measurements between assessments in and 24 on the Lower Red Deer River...37 Table 11. Lower Red Deer River spring discharges at Red Deer during typical spring runoff months, and drought sequences preceding assessments in and vii

12 LIST OF APPENDICES Appendix 1. Appendix 2. Appendix 3. Appendix 4. Location and site summary data for sampling sections on the Lower Red Deer River in Lower Red Deer Phase II sample season windows...62 Lower Red Deer River turbidity and water quality data used to conduct Phase II of the study on the river in Comparison of species percent composition distributions by section between the assessment and initial sampling during the 24 assessment on the Lower Red Deer River....7 Appendix 5. Sauger age and length measurement relationships from the and 24 assessments on the Lower Red Deer River Appendix 6. Walleye age and length measurement relationships from the and 24 assessments on the Lower Red Deer River Appendix 7. Goldeye age and length measurement relationships from the and 24 assessments on the Lower Red Deer River Appendix 8. Mooneye age and length measurement relationships from the and 24 assessments on the Lower Red Deer River Appendix 9. Fork length frequency distributions for other species from the sport fish assessment on the Lower Red Deer River in viii

13 1. INTRODUCTION Effective management of sport fish populations depends, in part, on the availability of current information on their distribution and abundance. The Lower Red Deer River (LRDR) represents a 473 km river reach that supports a diverse assemblage of sport and non sport fish species. The status (distribution and abundance) of these species in the LRDR is poorly understood. Quantitative information on these species was most recently collected by Alberta Sustainable Resource Development (ASRD) in 199 and 1991 (ASRD, Red Deer, File data). However, revisions of the provincial status of many Alberta fish populations suggest that population densities can change relatively rapidly. Consequently, up to date information on fish populations in the LRDR is required to support responsible and proactive management. The purpose of this study was to assess sport fish distribution and relative abundance in the LRDR to provide current and relevant information to assist with management of several sport fish populations including walleye (Sander vitreus), goldeye (Hiodon alosoides), mooneye (Hiodon tergisus), sauger (Sander canadense), and northern pike (Esox lucius). Of particular concern is sauger, which has been designated as a Sensitive species (ASRD 21); although, anecdotal evidence from angler reports suggests the population has been increasing over the last ten years in the LRDR. Quillback suckers (Carpiodes cyprinus) also occur in the LRDR and are also of special interest because the status of this species in the province is currently undetermined, and the species is considered Data Deficient (ASRD 21). To undertake the assessment of the status of fish species in the LRDR, two separate phases of study were implemented. Phase I (the planning stage) was conducted in 23 and included preliminary reconnaissance of the river to gather information on access, logistics, and to delineate study reaches within the study area (see Cooper and Council 24). Phase II (the implementation stage) was undertaken in 24, in cooperation with ASRD, to gather field data on distribution and abundance of sport and non sport fish along the 473 km stretch of the LRDR. Comparison of the results of this study (Phase II) to results from the earlier study on the LRDR in , and to results from other studies, will help illustrate long 1

14 term species population trends and will help assess the effectiveness of current sport fish regulations on the LRDR. 1.1 Phase II objectives The specific objectives of Phase II were to: i. Collect fish species abundance and distribution data in the proposed study area for sport and non sport fish species; ii. Analyze fish population and growth trends; iii. Assess relative fish catchability via the selected sampling methodology; iv. Compare species abundance, distribution, growth and population trends with previous assessments; v. Prepare a Phase II final report; and vi. Assess existing data deficiencies to direct future data collection priorities toward target species. 2. STUDY AREA The Red Deer River is one of four sub basins that constitutes the South Saskatchewan River Basin. The other three sub basins include the Bow, Oldman, and South Saskatchewan river basins. The Red Deer River is the largest of the sub basins with a watershed area of 46,998 km 2, representing 41% of the South Saskatchewan River Basin area (Longmore and Stenton 1981). Although the largest, the Red Deer River sub basin contributes only 18% of the mean, annual, natural flow of the South Saskatchewan River Basin, with the Bow, Oldman, and South Saskatchewan sub basins contributing 43%, 38% and.7%, respectively (Golder 23). 2

15 The Red Deer River originates in the Rocky Mountains, roughly 3 km within the eastern boundary of Banff National Park, northeast of Lake Louise, Alberta (Figure 1). The river begins a 78 km traverse eastward through the foothills boreal forest to Sundre (Roth 22). The river then flows northeast into the Parkland region, and is backed up by the only impoundment on the river, the Dickson Dam, which forms Gleniffer Reservoir. The river continues northeast through Red Deer and then south. A transition from Parkland to the Badlands region begins as the river nears Drumheller where it continues southeast toward Dinosaur Provincial Park. Finally, from the park onward, the river meanders easterly through the rolling grasslands across the Alberta Saskatchewan provincial boundary (Swenson 22), where it flows an additional 17 km in Saskatchewan before reaching the confluence with the South Saskatchewan River. The Red Deer River is unique to Alberta in that it flows through all five of Alberta s major ecoregions: mountain, foothills, boreal forest, parkland and prairie (Rood et al. 22). The lower two thirds of the Red Deer River from Joffre (Highway 11 bridge crossing) to the Alberta Saskatchewan border is 473 km long and represents about 67% of the entire watercourse. This section of river consists of a large, single, wide channel (89 m at Red Deer, 96 m at Drumheller, 168 m at Empress), with a mean depth ranging from.8 1. m, interspersed with islands and sand bars. This particular stretch of river has a very flat gradient (.8.3 m/km) and high turbidity levels downstream of Drumheller. The upper part of this section of river from Joffre to Drumheller generally consists of clearer water, with gravel streambeds in riffle areas, and long stretches of fine sand/silt substrate in pool and run areas. The lower part of the Red Deer River from Drumheller to the Alberta Saskatchewan border has a predominant sand/silt streambed and experiences a constant high level of turbidity (Longmore and Stenton 1981). These features contribute to a river that is relatively warm and slow moving. Cool water sport species are known to inhabit the lower two thirds of the Red Deer River, as well as warm water non sport species. Low discharge rates, low dissolved oxygen levels, high turbidity and high summer water temperatures are believed to be why fish populations and production in this stretch of river are limited and species abundance is low. 3

16 Red SASKATCHEWAN SCALE km ALBERTA Edmonton Red Deer River Watershed Calgary ALBERTA Alkali Creek River Study Section Watershed Boundary National Park Boundary Provincial Border City/Town Berry Deer River SUNDRE Banff National Park RED DEER DRUMHELLER River River Rosebud Blindman Gull Lake Medicine River Gleniffer Lake Sylvan Lake Deer River Deer Creek Red Dogpound Raven River Barrie Lake Buffalo Lake Pine Lake Marion Lake Shooting Lake Gough Lake Sullivan Lake Chain Lakes Dowing Lake Bullpound Coleman Lake Oakland Lake Creek Red Creek Ghost Pine Threehills Creek Creek Kneehills Creek N W E S River James Creek Fallentimber Little Figure 1. Map of the Red Deer River watershed showing the 473 km study section (map from Longmore and Stenton 1981). 4

17 3.. MATERIALS AND METHODS 3.1 Phase I Review of the study Phase I began with an information session with the ASRD Area Fisheries Biologist in Red Deer, Vance Buchwald, on how the previous assessment of the LRDR in was conducted, including sampling methodology, location of sampling sites, time of year of sampling, and a brief summary of capture results from Topographical maps with sample locations were obtained and the locations were converted into Universal Transverse Mercator (UTM) coordinates (NAD 83) using ASRD s Spatial Data Management Environment (SDME) Internet Mapping Framework (IMF) (Appendix 1). UTM coordinates were then put in a Global Positioning System (GPS) unit Ground reconnaissance Reconnaissance was conducted on the ground in June 23 to locate suitable launching sites for an electrofishing jet boat, with water levels in mind. Photos were taken and field forms developed. Logistic information was collected and included the location of nearest fuel facilities, campsites and accommodations, and supply facilities (to aid in partitioning the river into manageable daily sample sections). Information regarding sandbar locations and potential low water obstructions was also collected Water flow review Historical water flow data were compiled from Alberta Environment in an attempt to establish a sample window with sufficient flows to safely maneuver a jet boat, but with low enough discharge to effectively capture fish. Extensive historical review of spring discharge and consultation with Vance Buchwald (ASRD, Red Deer) and Conservation Officer Byron Jensen (ASRD, Drumheller), dictated that a reactionary approach to daily river conditions was imperative in order to complete Phase II of the project. 5

18 3.1.4 Known fish species composition A summary of fish species known to be present in the LRDR was compiled from previous assessments and literature. Lists of known sport fish and non sport fish species were produced to help predict the fish community that would likely be encountered, and to generate a suitable field fish identification key. The list of sport fish included: northern pike, sauger, mooneye, lake whitefish (Coregonus clupeaformis), yellow perch (Perca flavescens), burbot (Lota lota), lake sturgeon (Acipenser fulvescens), mountain whitefish (Prosopium williamsoni) and goldeye. Goldeye were expected to be the most numerous sport fish species present in this lower stretch of river (Longmore and Stenton 1981; B. Jensen, pers. comm.). Only a slight chance of encountering rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) was expected, and only in the uppermost part of the study section (Joffre area). The non sport fish species list included: emerald shiner (Notropis atherinoides), river shiner (Notropis blennius), spottail shiner (Notropis hudsonius), flathead chub (Platygobio gracilis), longnose dace (Rhinichthys cataractae), quillback sucker, longnose sucker (Catostomus catostomus), white sucker (Catostomus commersoni), shorthead redhorse (Moxostoma macrolepidotum), silver redhorse (Moxostoma anisurum), trout perch (Percopsis omiscomaycus), and spoonhead sculpin (Cottus ricei) (RL & L 1997). Other non sport fish species expected to be present in the LRDR according to Nelson and Paetz (1992) were: lake chub (Couesius plumbeus), pearl dace (Margariscus margarita), northern redbelly dace (Phoxinus eos), finescale dace (Phoxinus neogaeus), fathead minnow (Pimephales promelas) and brook stickleback (Culaea inconstans) River section division The study area is 473 km in length from the Highway 11 bridge crossing east of Red Deer to the Alberta Saskatchewan provincial boundary. Partitioning of the river into manageable, logistically feasible reaches was essential for the completion of the assessment. Based on ground assessments, personal communications, ortho photo interpretation, and launch / crossing locations, the 473 km reach of the LRDR was divided into 13 sections ranging from 26 to 49 km in length with between five to ten sample locations (reaches) per section (Appendix 1; also see Cooper and Council 24). This division resulted in a total of 95 1 km reaches along the river being identified for 6

19 sampling (Cooper and Council 24). Of these, 8 reaches corresponded (as closely as possible) to sites sampled during the study (see section 3.1.1). Details on these sites and the additional sample reaches not sampled during the survey are provided in Cooper and Council (24) Angling and fisheries management Based on the information collected during Phase I, it was concluded that angling pressure is considered light with very few anglers fishing by boat (B. Jensen, pers. comm.), and that pressure is typically heavy only at access points (bridges) where most anglers target goldeye, walleye, and sauger (Longmore and Stenton 1981). However, there has never been a comprehensive angler survey conducted on the LRDR. 3.2 Phase II water flow The minimum discharge required to safely jet boat the river was 5 m 3 /s at the Red Deer gauging station (Vance Buchwald, ASRD, pers. comm.). As a result, flows and river levels were scrupulously monitored on the Alberta Environment website (Alberta Environment 24) throughout the spring, leading up to and well into the recommended sampling window of late May through early July (Cooper and Council 24). When flows reached acceptable sustained levels, sampling commenced. Additional resampling of sites was conducted after the recommended timeframe had passed because flows remained suitable longer than expected (Appendix 2) Sampling methodology Jet boat electrofishing was used to capture fish. A Coffelt VVP 15 electrofisher and dual six dropper anode arrays on booms were used on a fiberglass Glascon river jet boat propelled by a 9 hp Evenrude outboard jet. As above, 8 sample sites from the fisheries inventory done in were sampled in 24 and were located using a Garmen Etrex GPS unit uploaded with UTM coordinates using Garmin MapSource Metro Guide Canada V4 Software. Electrofishing was conducted in a downstream progression starting at section 1 downstream of the Highway 11 bridge crossing and 7

20 ending at section 13 near the Bindloss bridge crossing. Sample locations were 1 km in length and occurred systematically every 5 km, representing a variety of riverine habitats (riffle, pool, run) through random chance (Cooper and Council 24). Upon arrival at a sample location, the boat was slowed to a drift and electricity was administered 1 s on and 8 s off, plus whatever additional output was deemed necessary to contain fish in the electrical field. Typically, electrofishing was conducted along the banks and in areas of cover; however, open water sections in the main channel were also sampled when habitat was homogenous. Measurements were recorded of electrofishing output in voltage and amperage, and effort in seconds. Captured fish were contained in a live well until the end of each respective 1 km sample stretch at which point fish were sampled and released back to the river. Fish data collection included species, condition, fork length (FL), weight, sex when possible, and non lethal aging structures. Capture locations were also recorded to verify species distributions throughout the watercourse. All species of sport fish greater than 25 mm FL were tagged with Hallprint T bar anchor fish tags. Tags were orange in color and were imprinted with a unique sequential identification number beginning at SER 12 and a phone number to facilitate voluntary reporting of recaptures by anglers. Occasional repeat sampling of sites was conducted in an attempt to establish fish catchability on given sampling events. Marked fish were released back to the section of stream in which they were initially captured and ratios of marked to unmarked fish captured on repeat runs were recorded. Throughout the course of electrofishing, many fish were observed but evaded capture. Consequently, a running tally of observed numbers of each species was initiated to account for readily identifiable fish that avoided capture. Some sections that were thought ineffectively sampled during initial spring sampling were subsequently resampled at a later date to validate first pass assessment results. Water conditions were recorded at intervals throughout the assessment. Water clarity was measured as the depth of visibility; the approximate measure of underwater distance (depth) that crewmembers can accurately identify subsurface features and fauna. Additional water quality measurements included water temperature and conductivity (Appendix 3). 8

21 3.2.3 Species distribution and abundance analysis All fish and site data were compiled into a Microsoft Access database and also housed in the provincial government s Fisheries Management Information System (FMIS) database. Species composition and distribution were determined from all fish tallied during initial spring sampling, summer resampling, and all catchability runs combined. Species distributions were determined based on presence/absence per river section on a per species basis, to assess continuity of distributions in the study area. Species presence by section was determined using only initial spring sampling. Species presence/absence was compared with results to examine possible changes in species distribution patterns and range. Proportionate species distribution by section was compared between 24 and assessments for four sport fish species and one non sport fish species to compare the percent composition of the species totals in relation to their locations in the study area. Species abundance per section was measured in terms of catch per unit effort (CPUE), observed fish totals, captured fish totals, and combined totals (observed and captured) per section. CPUE was calculated for all captured fish during initial spring sampling based on electrofishing effort. Total fish abundance on a per section and per sampled river kilometer basis was evaluated in an attempt to illustrate general fish productivity levels throughout the watercourse. Combined observed and captured totals per section were compared between 24 and assessments to illustrate trends in total fish productivity by location along the watercourse and change over time. Relative species abundance was measured in CPUE of boat electrofishing time as well as combined observed and captured fish totals. Comparisons of relative abundance between 24 data and data from were made using data from 8 sample locations that were similar between studies for total combined fish species, as well as per species. Paired t tests were used to compare results from the two assessments using JMP IN Statistical Discovery Software, version Capture and biological data analysis Biological data collected on all fish successfully captured and measured was used to assess catchability and investigate population structure and growth. 9

22 To assess catchability of fish, sites where all fish captured on the previous sampling event were marked were resampled. The subsequent ratio of marked to unmarked fish was intended to provide a ratio of the proportion of fish captured during a given sampling event, and thus reflect the ability to estimate total fish present per sampling location. Length data for captured samples of fish species were compiled into fork length frequency distributions to assess size class distribution trends per species and were compared with data. Length at age and age class profiles were produced for sport fish species with suitable non lethal aging structures and sufficient sample sizes. The profiles were compared with previous studies and/or other provincial rivers. Growth was assessed using von Bertalanffy growth equations (von Bertalanffy 1938) and growth equations were calculated using Fisheries Analysis and Simulation Tools (FAST) version 2. software. The von Bertalanffy (1938) growth equation is: L t = L (1 e k (t t ) ) where, Lt = length at age t, L = the asymptote or final maximum size, K = the rate at which the growth curve approaches the asymptote, and t = a time scaler, the hypothetical time when the fish was size zero. The parameter used to estimate growth in the von Bertalanffy model is K, which represents the rate at which the fish approaches maximum size (L ). Higher values of K represent faster growth and are usually associated with a lower L. Due to small sample sizes of small fish, t was fixed at zero to reduce bias in the growth function. 1

23 4. RESULTS Spring sampling commenced on 15 June at section 1 near Joffre and concluded on 29 June at section 13 near Bindloss. A total of 9 1 km reaches were sampled of the proposed 95 sample reaches (Appendix 1). Mechanical failure ended the survey 2 km short of the 47 km target objective; however an additional ten sample reaches were added to the survey area, representing an additional 45 km of river sampled in 24. A total of 19 1 km reaches were resampled on July from section 3 at km 385 to the first site in section 6 at km Species composition and relative abundance Nine of 12 potential sport fish species known to be present in the LRDR were captured in 24 (Table 1). Yellow perch, rainbow trout, and brown trout were not captured or observed during sampling. Nine non sport fish species were captured in the LRDR in 24. Of non sport fish previously captured in the LRDR (RL&L 1997), silver redhorse, spottail shiner, trout perch and spoonhead sculpin were absent from 24 samples. Lake chub was not captured in the earlier study, but was captured in 24. In total, 429 fish were captured through electrofishing. An additional 1,116 fish were observed (visually) but were not captured (Table 2 and Figures 2 and 3). Goldeye was the most abundant species in the study comprising the highest total CPUE via electrofishing with 1.48 fish/1 min captured during spring sampling. A total of 173 goldeye were captured and an additional 498 fish were observed (Table 2 and Figures 2 to 4). Important to note, when tallying observed fish, goldeye and mooneye were both considered goldeye due to the inability to distinguish them during visual counts. Sauger was the second most abundant species in terms of CPUE (.51 fish/1 min; Figure 2). However, in terms of total abundance, shorthead redhorse was the secondmost abundant species with a combined observed and captured total of 322 fish, followed by 18 white suckers and 132 sauger (Figure 4). Overall, goldeye comprised 43% of the total sample (i.e., captured and observed fish) followed by shorthead redhorse (21%), white sucker (12%) and sauger (9%). Walleye 11

24 comprised 4% of the total, while northern pike, mooneye and burbot each contributed 2%. Together, quillback sucker, longnose sucker, lake sturgeon, mountain whitefish and lake whitefish comprised the remaining 5% of the sample. Table 1. Fish species captured during the Lower Red Deer River sport fish assessment in 24. Family Common name Scientific name Code* Sport fish Acipenseridae Lake Sturgeon Acipenser fulvescens LKST Esocidae Northern Pike Esox lucius NRPK Gadidae Burbot Lota lota BURB Hiodontidae Goldeye Hiodon alosoides GOLD Mooneye Hiodon tergisus MOON Percidae Sauger Sander canadense SAUG Walleye Sander vitreus WALL Salmonidae Mountain Whitefish Prosopium williamsoni MNWH Lake Whitefish Coregonus clupeaformis LKWH Non sport fish Catostomidae White Sucker Catostomus commersoni WHSC Longnose Sucker Catostomus catostomus LNSC Shorthead Redhorse Moxostoma macrolepidotum SHRD Quillback sucker Carpiodes cyprinus QUIL Cyprinidae Lake Chub Couesius plumbeus LKCH Flathead Chub Platygobio gracilis FLCH Emerald Shiner Notropis atherinoides EMSH River Shiner Notropis hudsonius RVSH Longnose Dace Rhinichths cataractae LNDC *Fish species codes follow MacKay et al. (199). Summer resampling of three sections resulted in a total of 96 individuals, of which 98% were observed and 2% were captured. Totals from the resampled sections represented 59% of the total fish tallied in 24. Goldeye was again the most abundant species comprising 44% of the sample, shorthead redhorse 27%, white sucker 17%, walleye 4%, sauger 4%, northern pike 2%, quillback sucker 1%, and burbot and longnose sucker together the remaining 1%. 12

25 Table 2. Summary of measurements and species abundance for fish species in the Lower Red Deer River assessment in 24. Catch per unit effort (CPUE) is based on initial spring sampling conducted between June, and excludes resampling events between July. Species Total measured CPUE (# fish/1 min) Total observed Fork length (mm) Weight (g) Max Min Mean S.D. Max Min Mean S.D. GOLD MOON SAUG , NRPK , ,76 1,981 WALL , ,411 1,363 LKWH , MNWH BURB , LKST ,5 1,5 1,5 N/A N/A N/A N/A N/A SHRD , QUSC ,41 1,265 1, WHSC ,93 8 1, LNSC , FLCH 32 NA NA TOTAL ,116 13

26 2. Total effort = hours 1.5 N = N = 56 N = 31 N = 24 N = 24 N = 17 N = 14 N = 9 N = 8 N = 7 N = 6 N = 1 N = 1 GOLD SAUG MOON SHRD BURB WHSC WALL LNSC MNWH NRPK LKWH QUIL LKST Figure 2. Catch per unit effort (CPUE) by species during the initial sampling event using electrofishing on the Lower Red Deer River in N = N = N = GOLD & MOON N = 163 N = 7 N = 41 N = 11 N = 24 N = 16 N = 1 N = 2 SHRD WHSC SAUG WALL BURB NRPK QUIL LNSC LKST Figure 3. Observed total number of fish by species from all sampling events on the Lower Red Deer River in

27 N = 75 GOLD& MOON N = 1544 N = 321 N = 18 N = 132 N = 57 N = 38 N = 32 N = 18 N = 11 N = 9 N = 3 SHRD WHSC SAUG WALL BURB NRPK QUIL LNSC MNWH LKST Figure 4. Combined observed and captured fish totals by species from all sampling events on the Lower Red Deer River in Species distributions General distributions (based on species presence) varied between species as the fish community changed with habitat. With the exception of shorthead redhorse and goldeye, which were consistently present throughout the entire study area, there was a general decline in species richness downstream. This was particularly evident in sections 8 and 9 from the Finnegan Ferry crossing to Dinosaur Provincial Park where there was very low species diversity and abundance. Species diversity and abundance appeared to increase with proximity to the confluence with the South Saskatchewan River (Tables 3 to 7). 15

28 Table 3. Species capture totals by section during the initial spring sampling event on the Lower Red Deer River in 24. SPECIES SECTION * TOTAL BURB FLCH GOLD LKST 1 1 LKWH 6 6 LNSC MNWH MOON NRPK QUIL 1 1 SAUG SHRD WALL WHSC TOTAL *Only two sites were sampled in section

29 Table 4. Observed species totals by section during the initial spring sampling event on the Lower Red Deer River in 24. SPECIES SECTION 1** 2** * TOTAL BURB FLCH GOLD LKST LKWH LNSC MNWH MOON NRPK QUIL SAUG SHRD WALL WHSC TOTAL *Only two sites were sampled in section 13. **Observed totals in sections 1 and 2 were influenced by high turbidity levels. 17

30 Table 5. Combined captured and observed species totals by section for the initial spring sampling event on the Lower Red Deer River in 24. SPECIES SECTION * TOTAL BURB FLCH GOLD LKST LKWH 6 6 LNSC MNWH MOON NRPK QUIL SAUG SHRD WALL WHSC TOTAL *Only two sites were sampled in section

31 Table 6. Combined captured and observed species totals during resampling of sections on the Lower Red Deer River in 24. SECTION SPECIES * TOTAL BURB FLCH GOLD LKST LKWH LNSC 1 1 MNWH MOON NRPK QUIL SAUG SHRD WALL WHSC TOTAL *Only one sample site was resampled in section 6. 19

32 Table 7. Combined captured, observed and catchability totals by species from all sampling events on the Lower Red Deer River in 24. SPECIES SECTION 1 2 3* 4* 5* 6* * TOTAL BURB FLCH GOLD LKST LKWH 6 6 LNSC MNWH MOON NRPK QUIL SAUG SHRD WALL WHSC TOTAL ,544 * Denotes sample sections that were resampled (shaded). **Only two sites were sampled in section 13. 2

33 4.2.1 Total fish productivity by section Section 1 had the highest average CPUE per section with a mean of 11.5 fish/1 min of electrofishing and the highest maximum CPUE at any sample site in the study at 18.7 fish/1 min (Figure 5; Appendix 1). Sections with the next highest average CPUE values were section 13 with a mean of 7.18 fish/1 min and section 6 with a mean of 4.24 fish/1 min. Figure 5. Total catch per unit effort (CPUE) by river kilometer on the Lower Red Deer River in 24. After section 1, sections 6, and 11 through 12 were the next most productive sections in terms of total fish numbers with combined observed and captured fish totals of 75, 88 and 79 individuals, respectively (Table 5 and Figure 6). A comparison of captured versus observed fish totals showed similar river transects where peak numbers occurred, specifically sites in section 6 and sections 1 though 12 (Figure 7). However, in sections 1 and 2, fish were exclusively captured and not observed, and in section 4 fish were almost exclusively observed and not captured. Generally, there was a trend for totals of captured fish to be highly variable across study sections; whereas there was a general increasing trend in total numbers of observed fish (Figure 7). 21

34 Figure 6. Combined observed and captured fish tallies per river kilometer during the initial spring sampling event on the Lower Red Deer River in 24. Figure 7. Observed versus captured fish abundance per section on the Lower Red Deer River in

35 Clear water resampling of the least productive sections from the early sampling period (sections 3 through 5 and one site in section 6) resulted in observed totals a full order of magnitude higher than the total number of fish enumerated in the same sections during initial sampling (Figure 8). Total fish caught and observed per site averaged only 1.2 fish during initial sampling but increased significantly to 47.7 fish/site during clear water resampling (P = <.1, df = 18). Figure 8. Comparison of combined observed and captured fish totals during initial spring conditions with observed totals from clear water resampling on the Lower Red Deer River in Fish catchability During the 24 assessment a total of four catchability runs were conducted with only two recaptures. Initial capture success was low because of avoidance, resulting in a corresponding low recapture success. Consequently, no meaningful ratio could be calculated. Evidence from observed totals (compared to total fish captured) and fish behavior (observed avoidance) suggested that only a small fraction of fish present within an area were successfully captured. 23

36 4.4 Sport fish species distribution and habitat observations Goldeye Goldeye showed the greatest abundance and the most continuous distribution throughout the 24 assessment (Tables 3 and 5). This species was frequently observed in large roaming schools, particularly during summer resampling when the water was extremely clear. Schools were tight and typically comprised of approximately 3 individuals, although schools as large as 6 individuals were observed. Fish were captured in a variety of habitats including deep pools, shallow riffles, inside and outside bends, near structure, and in flat open water with no apparent cover Mooneye Mooneye was present sporadically through the sample area. Mooneye was observed more frequently in upper reaches and was less prevalent in middle and lower reaches (Table 5). Mooneye was found in habitats similar to that of goldeye. Although mooneye may have been counted as goldeye during visual counts, capture rates suggest mooneye occur only in small numbers (Table 3) Sauger Sauger was consistently represented through most of the sample sections with the exception of middle stretches (sections 7 9) where all species were low in abundance (Table 5 and Figure 5). Sauger tended to occur in shallow water, which probably contributed to its relatively high CPUE due to the close proximity of the electrical field. Fish were frequently found in shallow fast moving riffle crest areas at tail outs of pools or runs and also in deeper pools and holding close to shoreline structure. Juvenile sauger were captured along with juvenile walleye in a shallow muddy rearing area vegetated by sparse rushes and flooded willows, near the Bindloss bridge crossing in section

37 4.4.4 Northern pike Northern pike was observed periodically, but in low numbers primarily upstream of Bindloss (Table 5). Pike occurred exclusively in locations of high vegetative cover, typically slow moving pools, and deeper runs or eddies with abundant aquatic vegetation or woody debris. Downstream of section 6 (Drumheller), the species was less abundant as the river channel became more broad and open Whitefish Both lake whitefish and mountain whitefish were captured in small numbers in only the uppermost portions of the study area (Tables 3 and 5). Whitefish were captured concurrently with goldeye in a variety of habitats. Distribution of whitefish is likely limited by temperature tolerances, as downstream maximum summer temperatures exceed whitefish tolerance limits (Longmore and Stenton 1981) Walleye Walleye was present in moderate abundance in the upper and lower portions of the study area. Walleye occurred sparsely in sections 2 through 9 (Table 5). Fish were located primarily in deep pools and occasionally in faster moving runs. Walleye capture success was likely poor because of its deep water habitat preference, positioning it beyond the reach of the electrical field. Large walleye were observed at the bottom of deep pools and were not affected by the electrical field. Walleye were also observed lying in direct contact with the river bottom, which is common for sauger but not typically of walleye (Nelson and Paetz 1992). 25

38 4.4.7 Lake sturgeon Lake sturgeon was first observed and recorded in section 6 while traveling between sample sites. This individual was identified during an acrobatic leap directly in line with the boat s trajectory of travel. The first and only lake sturgeon captured was also in section 6 near the hamlet of Dorothy. An additional sturgeon was observed near Jenner in section 11 where large, deep pools were documented Burbot Burbot was continuously distributed throughout most of the study area in small numbers (Table 5). Fish were observed where large substrate, vegetation, or cover persisted, and were also observed in the broad, open channel portion of the river. 4.5 Non sport fish species distributions Shorthead redhorse Shorthead redhorse was the most abundant and most widely distributed of the four sucker species captured during the survey (Table 5), and had the second largest numbers of any species throughout the study area. Shorthead redhorse were observed in slow moving, shallow stretches with all kinds of substrates including rocky, vegetated or clay/sand bottoms. During the summer resampling, large schools of 25 5 individuals were observed White sucker White sucker was found mainly in the upper portion of the study area but was also represented in lower reaches (Table 5). Large white suckers were captured individually in slow moving eddies and pools and in areas of cover. Smaller white suckers were typically found in large schools, with as many as 45 individuals (Table 6), over a variety of substrates including rocky, silty and vegetated bottoms. 26

39 4.5.3 Longnose sucker Longnose sucker was sporadic in its distribution throughout the study area and occurred only in small numbers (Table 5). Longnose suckers were typically found individually, but occasionally they were observed within schools of other sucker species Quillback sucker Quillback sucker occurred in a few small, isolated groups in sections 4 through 6 and sections 11 through 12 (Tables 5 to 7). Its distribution may be linked to specific habitats, although no obvious habitat observations were made at capture locations. Quillbacks were observed individually or in small schools of up to four fish. The species was also observed schooling with other sucker species. Quillback sucker numbers may be low because successful capture occurred late in the study. Confident visual identification was possible only during sampling events occurring in and around that timeframe. Summer resampling allowed for verification of visual identification because of clear water conditions Flathead chub Flathead chub was observed in the middle and lower sections of the study area and was often the only species captured at sample locations where river habitat was marginal. Flathead chub was relatively continuous in its distribution from section 5 through section 13 and was the only species that appeared more abundant in a downstream progression (Table 5). The species was not captured in section 9; however, the turbid conditions in lower reaches and a focus on larger size classes and sport fish species may have resulted in flathead chub being overlooked in this particular section Other non sport fish species Four other minnow species observed throughout the study were lake chub, emerald shiner, river shiner and longnose dace. Counts of these species were not recorded in order to focus netting and tallying of larger fish and priority species. Likewise, the 27

40 locations and distributions of these minnow species were not systematically documented. 4.6 Comparison of 24 and data Species composition and relative abundance Species composition and species diversity differed slightly between the 24 and assessments. A total of 18 fish species were captured in 24 compared with 14 species in Two sport fish species, lake whitefish and lake sturgeon, were represented in 24 but were not encountered in the study. Three non sport fish species, lake chub, river shiner, and longnose dace, were also captured in 24 but not in the earlier study. Fathead minnow was present in the study, but was absent in 24. In , a total of 858 fish were captured across the 8 sample sites. All fish captured during that study were sport fish and included goldeye, mooneye, walleye and sauger. In 24, a total of 282 fish of these four species were captured across 19 sample sites (Figure 9). In 24, the combined totals of all sport fish and non sport fish species was 429 fish, exactly half the capture total represented by only the four sport fish species. No fish were captured in 19 of 9 (21%) of sample sites in 24. In comparison, only 9 of the 8 sites (11%) sampled in resulted in zero captured fish. Combined observed and captured fish totals between the two studies using data from the initial capture event in 24 showed a 7% decrease in total fish abundance between study years, and a 26% decrease when data for 24 included captures from initial sampling and resampling (Figure 1 and Table 8). The 24 study area included 1 additional sample sites more than the study, and 19 sites were resampled. 28