RECOMMENDATIONS FOR MASS MARKING HATCHERY-REARED TROUT AND SALMON STOCKED INTO THE GREAT LAKES BASIN

Transcription

1 RECOMMENDATIONS FOR MASS MARKING HATCHERY-REARED TROUT AND SALMON STOCKED INTO THE GREAT LAKES BASIN A report of the Mass Marking Task Group to the Council of Lake Committees The following individuals participated in the Task group Participant Mark Ebener Greg Wright Gary Whelan Tammy Newcomb Dave Clapp Charles Bronte Curt Friez Jim Markham David Knutzen Stan Moberly Allison Niggemyer Matt Engel Chuck Krueger Marg Dochoda Bill Horns Paul Peeters Brad Eggold Steve Fajfer Brian Breidert Dylan Sickles David McLeish Gord Durant Bruce Morrison Lloyd Mohr Roger Kenyon Agency Chippewa/Ottawa Resource Authority/Great Lakes Fishery Commission Chippewa/Ottawa Resource Authority Michigan Department of Natural Resources Michigan Department of Natural Resources Michigan Deptartment of Natural Resources United States Fish and Wildlife Service United States Fish and Wildlife Service New York Department of Environmental Conservation Northwest Marine Technology Northwest Marine Technology Great Lakes Fishery Commission Great Lakes Fishery Commission Great Lakes Fishery Commission Great Lakes Fishery Commission Wisconsin Department of Natural Resources Wisconsin Department of Natural Resources Wisconsin Department of Natural Resources Wisconsin Department of Natural Resources Indiana Department of Natural Resources Indiana Department of Natural Resources Ontario Ministry of Natural Resources Ontario Ministry of Natural Resources Ontario Ministry of Natural Resources Ontario Ministry of Natural Resources Pennsylvania Boat and Fish Commission April 11,

2 TABLE OF CONTENTS EXECUTIVE SUMMARY...1 INTRODUCTION...2 RESEARCH AND ASSESSMENT QUESTIONS...3 COMPARISON OF MASS MARKING APPROACHES...5 DESIRED CHARACTERISTICS OF A MARKING METHOD... 5 EVALUATION OF MASS MARKING METHODS... 5 SUMMARY OF MARKING METHODS AUTOMATED FIN CLIPPING AND CODED WIRE TAGGING...13 MARKING LOGISTICS CAPITAL AND OPERATIONAL COSTS MARK RECOVERY AND INFORMATION MANAGEMENT...19 SAMPLING STRATEGY MARK RECOVERY COSTS TAG RECOVERY AND INFORMATION CENTER POLICY ISSUES...25 TASK GROUP RECOMMENDATIONS...27 REFERENCES...28 APPENDIX 1 DEMONSTRATION PROJECT...29 APPENDIX 2 DISINFECTING THE AUTOFISH TRAILER...34 APPENDIX 3 COST OF VARIOUS MARKING METHODS...38 APPENDIX 4 SALMONIDS SAMPLED IN CREEL SURVEYS

3 EXECUTIVE SUMMARY The Council of Lake Committees (Council) created the Mass Marking Task Group in October 2004 to develop a phased implementation plan of coordinated, basin-wide, mass marking of hatchery-reared trout and salmon stocked into the Great Lakes using the automated clipping and coded-wire tagging technology developed by Northwest Marine Technology. The Council asked the Task Group to identify the potential impediments to such a program and to suggest solutions to those impediments. The Council members also asked the Task Group to compare the cost of the automated system with other mass marking techniques. In response to the charge, the Task Group has 1) identified three high-priority information needs and numerous research and management questions that could be answered by a mass-marking program; 2) compared the costs of the various mass-marking techniques to the automated system and assessed the ability of each technique to answer the high-priority information needs and research and management questions; 3) estimated the initial capital costs and annual operating budget for using the automated system; 4) defined and estimated the cost of a strategy for sampling marked salmonids in the Great Lakes; and 5) described the logistics of processing and disseminating information on recovered marked fish. The Task Group recommends that a coded-wire marking and adipose fin-clipping program using the automated system is the most suitable mass marking method for the Great Lakes basin. The Task Group considered six mass marking approaches: oxytetracycline, strontium chloride/isotopes, passive integrated transponders, manual adipose fin clips, manual coded-wire tags, and thermal marks. Oxytetracycline, strontium chloride/isotope, and passive integrated transponders were not considered viable marking techniques. Manual adipose clipping was a viable and inexpensive mass marking technique, but it could not answer all three high-priority information needs, nor could it answer most of the research and management questions. Both manual and automated tagging and clipping could answer all three highpriority information needs and all the research and management questions, while thermal marking could answer less than one-half of the research and management questions. Additionally, the number of unique thermal marks is limited and this technique has the highest classification error rate of any of the marking techniques investigated. Thermal marking does not provide a substantial savings over a coded-wire marking program unless all salmon and trout stocked in the Great Lakes Basin are marked with a coded-wire tag, which the Task Group believes is unnecessary. Last, there was not a substantial difference between the cost of manual and automated coded-wire tagging and thermal marking. The Task Group recommends a long-term strategy of adipose clipping 100% of trout and salmon stocked into the Great Lakes each year and coded-wire tagging 50% of the salmon and 100% of the lake trout stocked each year. Twelve model SCT-6 Autofish Trailers would be needed to implement this recommendation. The cost to implement this program in the first year would be $15.5 million; $12.7 for capital costs and $2.8 million for annual operating expenses. A scaled-back proposal was developed, as requested by the Council, that would adipose clip 100% of Chinook salmon stocked into Lakes Michigan and Huron and 100% of steelhead stocked into Lake Erie, and codedwire tag 50% of the Chinooks stocked in Lakes Michigan and Huron and 50% of the steelhead stocked in Lake Erie. The cost of the alternative proposal ($12.2 million) was not substantially cheaper than the long-term strategy because there is only a 45 day time period in which Chinook salmon can be clipped and marked; therefore, a similar number of Autofish Trailers is still needed to accomplish the alternative proposal. Successful implementation of a mass-marking program for the Great Lakes is dependent upon the logistics, coordination efforts, and costs associated with tag/mark recovery, processing, and database management. Council member agencies must adopt a statistically rigorous strategy for sampling marked salmonids in predefined spatial areas of the Great Lakes. Fishery-independent surveys, creel surveys, and weir harvests conducted by Council member agencies, combined with a headhunter-type mark collection initiative, would provide the necessary sample sizes for answering all the high-priority information needs and research and management questions. A headhunter-type sampling program would cost 90% less than trying to collect the same number of samples through a routine creel survey. 1

4 The Task Group recommends that the U.S. Fish and Wildlife Service Fishery Assistance Program establish a central tag recovery and database maintenance infrastructure for the Great Lakes basin. Each fishery agency will be able to process their recovery data, but all information for each coded-wire tag recovery should be provided to the U.S. Fish and Wildlife Service for consolidation into a basin-wide database that can be disseminated to all agencies, and analyzed in a coordinated effort. The tag recovery and information center would cost $454,000; $132,000 in capital costs and $322,000 in annual operating expenses. U.S. Fish and Wildlife Service staff could process a maximum of 160,000 coded-wire tags each year at a cost of about $2.38 tag. The Task Group also addressed policies regarding ownership, maintenance and staffing of the Autofish Trailers, sources of funding for the mass-marking initiative, data-sharing agreements, and oversight of the mass-marking program. The Task Group recommends that ownership and operation of the Autofish Trailers should be the responsibility of U.S. Fish and Wildlife Service, either the Hatchery Program or Fishery Assistance Program. There must be at least 1.5 operators for every Autofish Trailer, and these operators will initially require six months of training. The U.S. Fish Wildlife Service Great Lakes Fish and Wildlife Restoration Act is the most logical legislative vehicle through which to seek funds to pay for the capital and operational costs of the mass-marking program, but the Council will have to develop a strategy for moving the mass-marking initiative forward in Canada. The Task Group recommends establishment of a new Task Group whose charge would include working cooperatively with Great Lakes Fishery Commission and U.S. Fish and Wildlife Service staff to secure U.S. federal funding and working cooperatively with the Province of Ontario to secure Canadian federal or Provincial funding. There must be data sharing agreements developed with Ontario and possibly among other agencies within the basin to insure that large-scale databases are accessible and useable. Lastly, the Task Group recommends that the Council charge the newly formed Task Group to develop a memorandum of agreement or protocol for identifying how the mass marking trailers would be used and allocated on an annual basis among marking projects. There is considerable commitment within the Great Lakes basin to implement a mass-marking strategy, yet the success of implementing such a strategy hinges on the ability of the Council and its member agencies to coordinate tag/mark recovery efforts and to cooperatively achieve, analyze and disseminate the recovery information. INTRODUCTION The fisheries of the Great Lakes represent an enormous economic, social, and cultural asset to the region. The large number of organized groups that are active proponents of the resource reinforces the importance of the fisheries. Resource managers and policy makers must use scientific information for making decisions regarding management of the fishery resources. Long-term data sets from consistent monitoring, gathered largely from surveys coordinated among agencies on each lake, provide the scientific information used to develop a unified approach for managing both wild and hatchery-reared fish populations and the fisheries that exploit them. Coordinating stocking and marking of salmonines has been difficult in the Great Lakes because of lack of agreement and participation among the eight states, two federal governments, Province of Ontario, and numerous Native American Tribes and Canadian First Nations responsible for fisheries management. Insufficient funding for marking and recovery efforts, combined with philosophical differences among agencies, have impeded our ability to assess the levels of natural reproduction, survival, movement, and contribution of stocked fish to extant populations in the Great Lakes. The need for a coordinated approach to monitoring salmonine populations and their fisheries has been amplified by the continued disruption of food webs from invasive species and the dynamic nature of the Great Lakes. Decision-making regarding stocking, tracking progress of lake trout rehabilitation, and assessing the health of aquatic 2

5 ecosystems require that the fishery agencies consider the efficiencies, accountability, and management options that would result from a coordinated mass marking effort of all salmonines stocked in the Great Lakes. In recognition of the need for a coordinated mass-marking program, the Council established the Mass Marking Task Group. The Task Group, composed of fishery biologists, managers, and hatchery specialists, was established to develop a phased implementation of coordinated basin-wide mass marking of stocked salmonines in the Great Lakes using the automated clipping and coded-wire tagging technology developed by Northwest Marine Technology (NMT). Northwest Marine Technology markets an automated system that can count and sort 10,000 salmonines of 57 to 142 mm long per hour, and adipose clip and/or adipose clip and coded-wire tag 42,000 fish in eight hours with only 1-2 people. The Task Group was specifically asked by the Council to identify the potential impediments to a coordinated mass-marking program using this automated marking technology (called SCT6 by NMT) and to provide solutions to those impediments. The Council also requested that the Task Group compare the cost of the automated system with other mass marking technologies (i.e. thermal marks, isotopes, oxytetracycline). This report Identifies research and assessment questions that could be answered with mass-marking technologies; Compares several mass marking approaches and recommends the most appropriate approach; Describes the logistics associated with the recommended mass-marking approach; Estimates the capital and operational costs of the recommended approach; and, Describes the costs, logistics, and organizational structure necessary to coordinate, analyze and disseminate the information on the recovery of marked fish. RESEARCH AND ASSESSMENT QUESTIONS A variety of research and assessment questions have been identified by the Task Group that can be answered confidently by increasing the proportion of marked salmonines. Additionally, increasing the proportion of marked fish provides fishery managers the option of developing selective fisheries to protect selected wild or unmarked fish or selected marked fish while allowing increased exploitation of other marked fish. There are three high-priority, immediate information needs that require a coordinated mass marking approach: 1) In Lake Huron and Michigan, estimate Chinook salmon (Oncorhynchus tshawytscha) natural reproduction to determine survival and movement of stocked fish, and total stock sizes. 2) In Lake Erie, estimate steelhead (Oncorhynchus mykiss) natural reproduction, the contribution of stocked fish to the harvest, and measure survival and growth; and 3) In all five Great Lakes, determine survival, natural reproduction, movement, and rate of return to stocking location of lake trout (Salvelinus namaycush). In addition to these needs, a broader set of research and assessment information needs exist that can also be addressed by a lake-wide or basin-wide mass-marking program (Table 1). These needs are nested in the above three projects but are applicable to all salmonine populations: level of natural reproduction; age, growth, survival, and movement of fish; performance of stocked fish; method validation; and the implementation of selective fisheries. 3

6 Table 1. Research and management questions that can be addressed through a sustained mass-marking program in the Great Lakes. Questions listed below that address immediate information needs are noted with a bullet. Questions that address long-term information needs are noted with a bullet. Topic Question Answers Will Provide: Natural Reproduction What is the level (and annual variability) of salmonine natural reproduction in each Great Lake or specific tributaries? Better estimates of forage consumption for bioenergetic modeling and formulating stocking strategies. Age, Growth, Survival, and Movement Performance of Stocked Fish Method Validation Selective Fisheries At what age do different strains of steelhead mature? How much movement of Chinook salmon and lake trout occurs between lakes? Do growth, survival, mortality, and exploitation rates vary spatially and temporally for trout and salmon? Does age at maturity for Chinook salmon change in response to changes in growth rates? Do returns to the fishery and stocking sites vary by strain, hatchery, rearing procedures, stocking method, and stocking location? Does size at stocking affect survival? Will pulse stocking (stocking specific locations at high densities) of lake trout at different locations improve survival? What is the best time of year to stock fish to maximize survival? How many stocked fish do not smolt and remain in streams the first year?? What are the rates of inter-lake exchange of stocked fish? Does the disease history of fish affect post-stocking survival? Do different tagging/marking methods affect the incidence of BKD? Does culling of eggs from diseased individuals improve the health of progeny? How accurate are current estimates of age composition of catch or of populations and what is the variation around these estimates? Which techniques provide the most reliable estimate of trout and salmon age composition? What is the accuracy of using chemical or isotopic signatures to determine environmental origin? Can Great Lakes fisheries be effectively managed by regulating harvest of marked and unmarked fish? Can we create specific fisheries (i.e.; locations, pier vs. boat, etc.) by varying stocking practices? Does hatchery or wild origin influence angler harvest or behavior? Better estimate forage consumption by accounting for interlake recruitment. Assess risk related to fish disease transmission. Estimate losses due to post-stocking non-migration of smolts and effects on naturalized fish production or resident stream fishes. Optimize stocking for greater survival of trout and salmon according to strain, size, rearing practice, disease control, and stocking location. This will improve hatchery performance and increase cost benefit ratios associate with agency stocking programs. Evaluate efficacy of existing methods and improve analytical techniques such as aging. To determine confidence in estimates that the existing methods produce and the amount of uncertainty in decisions based upon them. Evaluate the potential for, and effects of, a selective fishery because hatchery fish can be readily identified by anglers. Protect wild lake trout or steelhead. Reduce mortality on naturally wild steelhead in Lake Superior. Understand our stakeholders preferences and provide a venue for further dialogue of accountability with hatchery programs. 4

7 COMPARISON OF MASS MARKING APPROACHES Fulfilling the three high-priority information needs is essential for estimating forage consumption and assessing the progress of lake trout rehabilitation efforts, and using a coordinated multi-agency mass marking approach to fulfill information needs has been done before. From 1990 to 1995, fishery agencies cooperated to mass mark or tag Chinook salmon stocked into Lake Michigan with the goal of quantifying natural reproduction (Rutherford et al. 2002). This cooperative initiative was met with limited success due to variable mark quality, variable quality control, and lack of a coordinated lake-wide sampling program (Rutherford et al. 2002). However, it did allow the evaluation of the best marking and sampling methods for estimating natural reproduction (Rutherford et al. 2002; Szalai and Bence 2002). Rutherford et al. (2002) compared six possible mass marking methods to estimate Chinook salmon natural reproduction. We have updated and customized this information where required to address the three high-priority information needs, and the other research and assessment questions (Table 1). DESIRED CHARACTERISTICS OF A MARKING METHOD For a mark to address all information needs it must have the following characteristics: A duration that is matched to the longevity of each species; i.e. four years for Chinook salmon and ten or more years for lake trout Ability to create multiple, unique marks Must be applied quickly High marking success and high retention Easy to identify or detect Induces negligible mortality at marking and while the fish is at large Minimal human handling Correct classification rate error below 10% (Szalai and Bence 2002) Suitable for use by all Great Lakes fishery agencies Proven and tested For a large-scale mass-marking program to function effectively regardless of the information needs, the program should have the following characteristics: A standardized mark application procedure used by all hatcheries Quality assurance/quality control protocols at all hatcheries and recovery sources Measurement of between-reader error Quantifiable classification error rate EVALUATION OF MASS MARKING METHODS Six mass marking approaches were considered: antibiotic oxytetracycline (OTC) marks, strontium chloride/isotope marking, passive integrated transponder (PIT) tagging, manual adipose fin clips, manual coded-wire tags, and thermal marks. OTC marking, strontium chloride/isotope marking, and PIT tagging were not considered in detail in this analysis because the Task Group determined that these methods do not possess the desired characteristics, as described above, and our reasons are provided below. The Task Group estimated the cost of each mass marking method in addition to evaluating the ability of each method to fulfill the information needs and research and management questions. The cost for any massmarking program can be separated into capital and operational costs, which include mark detection and data 5

8 entry. Capital costs are one-time expenditures to acquire the infrastructure necessary to apply and detect the chosen marking method. In contrast, operational costs are incurred on an annual, recurring basis. Because the costs of implementing any marking program can vary greatly based on a number of factors (number of fish marked, number of marks decoded, etc.), we calculated the costs for each potential marking method over a range of mass-marking projects to facilitate comparison. OTC marking This technique is not recommended because it is not suitable for use by all Great Lakes fishery agencies. Some agencies are resistant to using an antibiotic for purposes other than treating disease and are concerned about the human health consequences of purposefully placing antibiotics in public waters. The Fish Culture Section of the Ontario Ministry of Natural Resources has developed a policy that specifically recommends against using OTC to mark stocked fish. The state of Illinois has already abandoned OTC as a marking tool, and the states of Wisconsin and Michigan are following. Strontium chloride or isotope marking This technique is not recommended for use because of annual environmental variability in isotopic elemental signatures (Rutherford et al. 2002). It would also be necessary to characterize the isotopic profile of all candidate hatchery fish by strain and year to establish the reference baseline used in the classification system (Schaner et al. 2004). This technique is better suited to determining the environmental histories of individual fish or the natal origin of individual wild fish than it is to marking groups of fish on a large scale (Rutherford et al. 2002). This technique is currently under development and while it has been somewhat successful in determining origin of lake trout in Lake Ontario (Schaner et al. 2004), it has been largely unsuccessful in determining origin of Lake Ontario Chinook salmon smolts (Nathan Smith, Old Dominion University, personal communication). PIT tagging PIT tagging is an attractive marking method for small releases of salmonids (less than 1000) but is not practical for a basin-wide mass-marking program involving millions of fish. PIT tags are used to identify individual fish or small groups of individuals. The tagging rate is too slow ( fish per hr) (Rutherford et al. 2002) to be logistically feasible for a basin-wide program. Lastly, each PIT tag costs about $5.50 (Rutherford et al. 2002), making the technique economically unfeasible for a basin-wide mass marking effort. For example, it would cost $55 million to fit 30% of the salmonids in the basin with PIT tags. Manual Adipose Fin Clipping Adipose fin clips are a simple way to mark hatchery-reared fish. Adipose fin clipping has many desirable characteristics including: Suitable mark retention rate High marking rate (approximately 6,400 fish per day per person) Suitable marking success Easy identification Negligible mortality Negligible classification error 6

9 Suitable for use by all Great Lakes fishery agencies Easy to standardize among hatcheries Proven and tested Manual adipose fin clipping has three undesirable characteristics: Requires considerable human handling Uses an anesthetic Does not provide a variety of unique marks Manual adipose fin clipping could be used to estimate natural reproduction of Chinook salmon in lakes Michigan and Huron and steelhead in Lake Erie, but could not be used to assess the annual variation in natural reproduction because there is no way to unambiguously distinguish among year classes. Annual variation in natural reproduction can only be detected by uniquely marking each year class of hatchery fish (Szalai and Bence 2002). Therefore, manual adipose clips could not be used to improve estimates of natural reproduction and forage consumption, nor could it be used to estimate growth, survival, origin, age structure or movement of steelhead in Lake Erie or lake trout in each Great Lake. Manual adipose clipping has the potential to address only four of the identified research and assessment questions (Table 2). The biggest limitation with adipose fin clips is that they provide only one unique batch mark. Capital costs associated with manual adipose clipping are minimal because hatcheries are already equipped to apply this method. Detection is simple, and therefore few costs exist to detect the mark. Operational costs for manual adipose fin clipping have been estimated to range from $0.015 to $0.020 per fish (Hammer and Blankenship 2001; VanDerLaan 2004). Mark detection and data entry costs are negligible for manual adipose fin clips because only recognition of the obvious external mark is required. Overall, costs for an adipose finclipping program are directly proportional to the number of fish clipped because there are no detection costs. Thermal Marking Thermal marking is accomplished by short-term water temperature fluctuations in the hatchery to produce distinctive alternative light and dark banding pattern onto otoliths of sac fry. The variation in water temperatures and exposure times determines the banding pattern. Thermal marks can be produced by altering water temperatures over a wide time frame of several hours to several days (Volk et al. 1999). To read the mark, the otolith is extracted from the fish at recapture, sectioned, and examined microscopically by a trained reader to determine the banding pattern. Thermal marking has many desirable characteristics High mark retention rate. Marks are retained for many years - shown to last for seven years with 100% recognition (Bergstedt et al. 1990). Applied quickly in large numbers of fish High success rate of creating marks - greater than 95% (Rutherford et al. 2002). Negligible mortality (Volk et al. 1999; Bergstedt et al. 1990) No human handling or anesthetic Applied to very early life stages - eyed-eggs and fry Proven and tested - about one billion juvenile salmonids are thermally marked in the North Pacific Thermal marking also has many undesirable characteristics 7

10 Table 2. Comparison of mass marking approaches that could be used to answer the research and management questions listed in Table 1. Questions listed below that address immediate information needs are noted with a bullet. Questions that address long-term information needs are noted with a bullet. Y = it is reasonable to expect that the specified approach can be used to answer the question; p = it may be possible to use the specified approach to answer the question (caveats specified); = it is unreasonable to expect that the specified approach can be used to answer the question Topic Natural Reproduction Age, Growth, Survival, and Movement Performance of Stocked Fish Research or Management Question What is the level of trout and salmon natural reproduction in each Great Lake? What is the level of trout and salmon natural reproduction in specific tributaries? What is the year-to-year variation in trout and salmon natural reproduction within each Great Lake? What is the year-to-year variation in trout and salmon natural reproduction within specific tributaries? At what age do different strains of steelhead mature? Adipose fin clip only CWT only Thermal marking CWT + ad clip Y Y Y Y Y p 1,2 Y Y Y 2 Y Y Y Y p 2,3 Y How much movement of Chinook salmon and lake trout occurs between lakes? Y p 1,2 Y Do growth, survival, mortality, and exploitation rates vary spatially and temporally for trout and salmon? Y Y Does age at maturity for Chinook salmon change in response to changes in growth rates? Y Y Do returns to the fishery and stocking sites vary by strain, hatchery, rearing procedure, stocking method, and stocking Y Y location? Does size at stocking affect survival? If so, what size at stocking maximizes survival (and reproduction)? Y p 1,2 Y Will pulse stocking (stocking specific locations at high densities) of lake trout at different locations improve survival? Y Y 8

11 Table 2 cont d Topic Performance of Stocked Fish Method Validation Selective Fisheries Research of Management Question What is the best time of year to stock fish to maximize survival? How many stocked fish do not smolt but remain in streams? What are the rates of straying or inter-lake exchange of stocked fish? Does the disease history of fish affect post-stocking survival? Adipose fin clip only CWT only Thermal marking CWT + ad clip Y Y Y Y Y Y Y p 1,2 Y Y Y Do different tagging/marking methods effect the incidence of Requires use of more than one method BKD? Does culling of eggs from diseased individuals improve the health of progeny? Y Y How accurate are current estimates of age composition of catch or of populations and what is the variation around these estimates? Y Y Which techniques provide the most reliable estimate of trout and salmon age composition? Y Y What is the accuracy of using chemical or isotopic signatures to determine environmental origin? Y p 1,2 Y Can Great Lakes fisheries be effectively managed by regulating harvest of marked and unmarked fish? Y Y Can we create specific fisheries (i.e.; locations, pier vs. boat, etc.) by varying stocking practices? Y Y Does hatchery or wild origin influence angler harvest or behavior? Y Y p 1,2 Y 1 Only if evaluating fewer than elements or combinations of elements (statistical districts, tributaries, hatcheries, strains, lots, fish sizes, planting locations, etc.) 2 Because approximately marks are available, this question cannot be answered using thermal marking at the same time that other questions requiring substantial numbers of thermal marks are being answered. 3 Ageing would have to be completed using a method in addition to the marking method. 9

12 Limited number of unique marks which are not easily quantifiable - estimated to range from 20 (S. Campana, Bedford Institute of Oceanography, personal communication) to over 1000 (E. Volk, Washing Dept. of Fish and Wildlife, personal communication) Not visible externally - mark recognition requires multiple trained readers Considerable between-reader error % for mark detection and 10-57% for mark classification (Bergstedt et al. 1990) High classification error rates - range from 0 to 60% (Hagen et al. 1995; Volk et al. 1999; Vander Haegan et al. in press) Quality and recognition questionable - dependent on planned thermal mark, background thermal characteristics experienced by wild fish (Volk et al. 1999), and weather Consistency varies among agencies and hatcheries Complicated standardization procedure Chinook salmon reproduction in Lakes Michigan and Huron and steelhead natural reproduction in Lake Erie could easily be estimated using thermal marking because very few unique marks are required. Growth and survival of steelhead in Lake Erie may be addressed by this technique, provided that the total number of unique marks required for separate measures (i.e., survival and growth by spatial unit by hatchery by stocking strategy by year class) does not exceed the few number of unique marks available. Assessment of hatchery lake trout populations could not be addressed by thermal marking because the combination of unique marks required to address this need over multiple year classes would easily exceed the relatively few marks available. Thermal marking has the potential to address about half of the identified research and assessment questions (Table 2). Because the error associated with simply detecting a thermal mark is smaller than the error associated with correctly identifying the specific marking patterns (Bergstedt et al. 1990), thermal marking is most suitable for answering questions where few marks are required. The utility of thermal marking to address questions requiring a larger number of unique marks is difficult to assess. If each hatchery is properly equipped to create detailed thermal marks and if enough marking days are available, it is theoretically possible to create more than 1000 unique thermal marks when both the number of bands and the distance between the bands provide meaningful information (E. Volk, Washington Dept. of Fish and Wildlife, personal communication). Unfortunately, marking capacity is often limited by issues around water supply, egg take schedules, human schedules, and other logistical concerns (E. Volk, Washington Dept. of Fish and Wildlife, personal communication). While a large number of thermal marks are theoretically possible, the number of functionally useful unique marks is much less. Currently, Washington Dept. of Fish and Wildlife is using less than 25 unique thermal marks on Chinook salmon, Alaska is attempting to code 75 unique marks on pink salmon, and Canada is using approximately 24 unique thermal marks (D. Knutzen, Northwest Marine Technology, personal communication). The number of functionally useful thermal marks likely ranges between 20 and 100, but is probably closer to 20 in a mixed stock situation (S. Campana, Bedford Institute of Oceanography, personal communication). In addition to the relatively limited number of marks available, thermal marking has the highest error rates for classification of any of the marking techniques investigated. Reported classification error rates for mark detection range from 0-60%, as reported above. Bergstedt et al. (1990), Volk et al. (1999), Vander Haegan et al. (in press), and Hagen et al. (1995), illustrate that there is error associated with the ability to detect the mark and that there is also between-reader error that must be corrected. Additionally, the error rate for identifying a particular banding pattern increases with the number of bands and is generally higher than the classification error rate for mark detection alone. The error rates reported for published applications thus far exceed the recommended classification error rate of 10% suggested by Szalai and Bence (2002). The capital costs for installing thermal marking equipment in all hatcheries is unknown and beyond the scope of this report. Costs will vary based on the configuration of each facility s water source, power supply, and available space. General capital cost estimates have also been characterized as $20,000 per hatchery for 10

13 thermal marking equipment installation and $10,000-$100,000 per hatchery for retrofitting raceways depending on existing configurations. Hammer and Blankenship (2001) note that initial laboratory equipment costs can range from $500-$50,000 per hatchery. Capital cost estimates for installation of thermal marking equipment could be obtained from each agency, if the Council requested agencies to provide this information. On the other hand, operational costs for thermal marking are very inexpensive once hatcheries are equipped. The estimated operational cost associated with heating and chilling water is $0.001 per fish (Hammer and Blankenship 2001). As marking frequency and complexity are increased, the operational costs could increase. Mark detection/data entry costs are relatively high for thermal marks because of the need for otolith extraction and for trained technicians to prepare the otoliths and read the marks. Detection and data entry costs range from $ per fish (Hammer and Blankenship 2001). A summary of costs associated with a thermal marking program is illustrated in Table 3. Manual Coded Wire Tagging A coded-wire tag (CWT) is a 1.1 mm x 0.25 mm magnetized stainless steel wire marked with a binary code or numbers denoting a specific batch or individual codes. The tag is injected into the snout of a fish, and at recapture it is extracted and viewed under a microscope to determine the code. Coded wire tagging has many desirable characteristics Suitable mark retention rate Nearly unlimited number of unique marks, including batch and individual marks High marking rate (approximately 5000 fish/day/person) Suitable marking success Marks do not require a specially trained reader or multiple readers Minimal mortality Negligible classification error Suitable for use by all Great Lakes fishery agencies Easy to standardize mark application procedure Marking method is proven and tested No ageing needed Coded wire tagging also has undesirable characteristics Mark location may vary among tagging personnel Requires human handling and an anesthetic CWT marking could be used to fulfill all three of the high-priority information needs and could be used to answer the research and assessment questions (Table 2). There are an unlimited number of unique numbers available for a CWT, which results in virtually no limitations to experimental designs. For example, on the West coast, fishery agencies use approximately 1,600 new tag codes each year (Dietrich Schmitt, Northwest Indian Fisheries Commission, personnel communication). 11

14 Table 3. The estimated annual average costs for three example mass-marking programs, each with different clipping and tagging requirements. For each cost estimate, the mass-marking program was assumed to occur over 10 yrs and the capital costs associated with each method were amortized over 10 yrs. A range of costs is presented in cases where information about facilities and equipment from each hatchery would be required to get an exact estimate. A detailed description of each calculation and its assumptions is provided in Appendix 3. The costs presented in this table include the costs of marking fish, decoding the mark, and entering data into a database. The costs presented in this table do not take into account the costs of mark recovery (see Mark Recovery and Information Management ). Marking Method Manual adipose fin clip only Example Program A: This program represents clipping and marking (CWT or thermal marking) all salmon and trout in all 5 lakes. This example program is for demonstration purposes only and does not represent any of the proposals in this report. Manually ad clip 33.2 million fish: $498,000 - $664,000 Annual average cost range under different clipping and tagging requirements. Example Program B: This program represents clipping all salmon and trout in all 5 lakes and/or CWT of thermal marking 50% of all salmon and 100% of all lake trout in all Great Lakes (Proposal 1) 1. Manually ad clip 33.2 million fish: $498,000 - $664,000 Example Program C: This program represents clipping all Chinook salmon stocked into lakes Michigan and Huron, and all steelhead stocked into Lake Erie and coded-wire tagging 50% of all off these fish (Proposal 2) 1. Manually ad clip million fish: $180,795 - $241,060 Thermal marking Thermally mark 33.2 million fish: $1,779,200 - $3,300,200 Thermally mark million fish: $1,764,850 - $3,285,850 Thermally mark million fish: $1,666,027 - $2,628,027 Manually CWT 33.2 million fish: Manually CWT million fish: Manually CWT million fish: Manual CWT only $3,384,964 - $5,444,304 $2,179,564 - $3,419,519 $964,130 - $1,341,573 Manual adipose fin clip + CWT Manually ad clip 33.2 million fish and CWT mark 33.2 million fish: $3,882,964 - $6,108,304 Manually ad clip 33.2 million fish and CWT mark million fish: $2,677,564 - $4,083,519 Manually ad clip million fish and CWT million fish: $1,144,925-1,582,633 Automated CWT + ad clip Automatically ad clip 33.2 million fish and CWT 33.2 million fish: $5,476,944 Automatically ad clip 33.2 million fish and CWT million fish: $4,497,557 Automatically ad clip million fish and CWT million fish: $3,076,214 1 Proposals are further defined beginning on page The costs in this table differ from the costs shown in Table 6 (Proposal 1) and (Proposal 2) because the capital costs in this table have been amortized over 10 years and the cost shown is the annual average cost. The capital costs in Table 6 and Table 7 have not been amortized over time. 12

15 The capital costs of CWT marking in the Great Lakes basin will vary based on the existing or required equipment for each hatchery and the number of fish that need to be marked. Some manual CWT injectors are already available because they are currently widely used within the basin. Individual hatcheries would need to provide information on existing equipment to determine how many additional CWT injectors ($30,300 per injector) are needed to meet mass marking needs. Operational costs for a CWT program include the tags and labor, which will vary depending on the number of tags purchased and the local labor costs. General estimates for CWT marking range from $0.069 to per fish (Hammer and Blankenship 2001). Michigan DNR estimated their costs for CWT tagging activities at Wolf Lake Hatchery in FY2003 as $ per fish (VanDerLaan, 2004). The costs associated with extracting a CWT and entering the encoded information into a database were estimated as $3-5 per sample by Hammer and Blankenship (2001). The Washington Department of Fish and Wildlife estimate that their cost to deliver heads to a lab, extract the CWT, decode it, and enter data to be $3.35 per head (Mark Kimbel, Mass Marking Supervisor, Washington Department of Fisheries and Wildlife, Olympia, Washington, personal communications). Based on cost estimates for a tag recovery and information center in the Great Lakes and an assumed CWT extraction and reading rate of tags per day per person, a central processing center in the Great Lakes could decode CWTs from 164,000 fish each year at a cost of $2.38 per tag. Overall, costs for a CWT program are related to the number of fish marked and the number of heads read. The cost to apply the mark is less than the cost to detect the mark on a per fish basis, so the total cost of a CWT program is influenced by the ratio of number of fish marked to number of tags decoded. However, when the number of fish marked is orders of magnitude more than the number of tags decoded, the number of fish marked drives the cost of the total program. A summary of costs for a CWT marking program is illustrated in Table 3. SUMMARY OF MARKING METHODS We recommended that CWT marking combined with an adipose clip is the most suitable mass marking method for the Great Lakes Basin. Of the mass marking methods discussed above, a CWT marking program would address the greatest number of information needs listed in Table 1 and would likely provide enough flexibility to address future questions. A thermal marking program can address fewer than half of the research and assessment needs, and an adipose clip alone will address even fewer needs. Additionally, when the limited number of available thermal marks is combined with high mark classification error rates, thermal marking quickly becomes unattractive. The number of otoliths read most heavily influences the cost of implementing a thermal-marking program as well as the capital costs associated with equipping hatcheries for thermal marking. The cost of a thermal marking program (Table 3) becomes less expensive relative to CWT marking as the number of marked fish increases; thus, a thermal marking program only realizes savings when large numbers of fish are marked. AUTOMATED FIN CLIPPING AND CODED WIRE TAGGING We recommend that the SCT6 automated adipose fin clipping and CWT tagging system developed by Northwest Marine Technology be implemented in the Great Lakes basin. The system, which is contained within a large portable trailer, has many desirable characteristics including: High CWT retention rate of > 98% High fin clipping rate of >99% Nearly unlimited number of unique marks, including batch and individual marks High marking and tagging rate of approximately 42,000 fish per eight hour day Easily identifiable mark that is visible externally (adipose clip) 13

16 Easily detectable tags through electronic sampling equipment Negligible mortality of <0.01% Negligible classification error Suitable for use by all Great Lakes fishery agencies Mark application procedure automatically standardized Mark quality automatically uniform No special training required to read marks and multiple readers not required Marking method is proven and tested - Used in the Pacific Northwest to mark and tag 100 million hatchery-raised salmon each year No aging needed No human handling or anesthetic required Quality control/quality assurance statistics are generated automatically The number and size distribution of tagged and clipped fish is known The two undesirable characteristics of the SCT6 AutoFish system are that trained staff is required to operate it and there is a large capital investment to purchase the units. The capital costs of purchasing the AutoFish SCT6 System will vary based on the number of fish that are clipped and tagged. Capital costs include the price of the AutoFish System at $980,000 per unit and a storage building that will cost $500,000. Field detection of a CWT in the snout of a fish requires hand wands ($5,000 each) or large electronic tunnel detectors ($29,700 each). Annual operational costs for the AutoFish SCT6 System include the cost of two staff to run each trailer ($100,000 total for 2 staff, travel, fringe, and per diem), a program supervisor ($70,000), trailer maintenance ($6 per 1,000 fish), contract hauling for the systems ($5,000/trailer per year), building maintenance ($15,000), miscellaneous expenses (depends on trailer use: $4.25 per 1,000 fish tagged; $0.25 per 1,000 fish fin clipped), and tags ($64 per 1,000 fish tagged). The total operational cost varies depending upon the number of tags purchased and the miscellaneous expenses associated with the number of fish clipped (Table 3). The cost to extract, read and enter the information on a CWT into a database is estimated to be $2.38 per fish. Overall, costs for an automated fin clipping and CWT program are based on the number of fish clipped, the number of fish tagged, the number of tags decoded, the number of systems needed, and the estimated lifespan of the program. The expected lifespan of the marking program also becomes important because the capital costs are averaged over the lifespan of the project for comparison. The capital costs for use of the automated system determine the overall cost. A summary of costs for an automated marking program is illustrated in Table 3. IMPLEMENTING AN AUTOMATED MASS MARKING PROGRAM The Task Group agreed to present to the Council two proposals for implementing mass marking in the Great Lakes. Proposal 1 is recommended by the Task Group and will fulfill the identified information needs and research and management questions in the Great Lakes basin. Proposal 1: Adipose clip all trout and salmon stocked into the Great Lakes each year, and coded-wire tag 50% of all salmon and 100% of all lake trout stocked each year. Proposal 2 is a scaled-back version of proposal 1. The Task Group was specifically asked to evaluate this mass-marking scenario by the Council. Proposal 2 will not fulfill all of the identified information needs and 14

17 research and management questions in the Great Lakes basin because it does not include marking or tagging any lake trout. Proposal 2: Adipose clip all Chinook salmon stocked into Lake Michigan and Huron and all steelhead stocked into Lake Erie, and coded-wire tag 50% of all Chinook salmon stocked into Lakes Michigan and Huron and 50% of the steelhead stocked in Lake Erie each year. MARKING LOGISTICS At least 54 hatchery facilities, separated by 1,000 miles, exist within the Great Lakes, and annually raise and stock about 33 million trout and salmon. There are 15 hatchery facilities in Wisconsin, 13 in Pennsylvania, 9 in Michigan, at least 7 in Ontario, at least 4 in New York, 2 each in Indiana and Minnesota, and one each in Illinois and Ohio. Lake trout, brook trout, splake, Chinook salmon, coho salmon, rainbow trout, brown trout, and Atlantic salmon are raised at these facilities. Five different life stages of these species are stocked: fry, spring fingerling, fall fingerling, winter fingerling, and yearlings. The Task Group has created an ACCESS relational database that contains information describing the number, size, life stage, and species of fish reared at each hatchery in the Great Lakes basin. These data also reside in a Geographic Information Database that can be used to assist in understanding the logistics of moving the SCT6 AutoFish trailers around the Great Lakes. All calculations of capital and operational costs in this report are based on the following constraints 42,000 fish can be tagged and clipped per day with the new AutoFish SCT6 (84,000/day with a double shift), and working weekends) There is a 45 day time period to tag and mark winter and summer fingerlings There is a 1.5 month time period (45 days) to tag and mark spring fingerlings There is a six-month time period to tag and mark yearlings There is only a two-month time period to tag and mark fall fingerlings Fish are tagged and marked only during one eight hour shift per day (double shifts would reduce the number of SCT6 units required but add to labor costs) The SCT6 can be operated about 18 days per month Proposal 1 For Proposal 1, twelve SCT6 AutoFish Trailers would be needed based on the assumptions listed above and the information contained in Table 4. The state of Washington currently uses four SCT5 systems to adipose clip and CWT salmon, but they maintain 19 manual mass-marking trailers where fish are clipped and tagged by hand. Several other states and tribes have recently ordered or are implementing automated marking systems. The state of Washington has decided to use the SCT6 and has recently ordered 5 units because it possesses superior marking and tagging quality (compared to the manual systems), is economical to operate, and is constructed to allow both automated and manual methods to be deployed in the same unit simultaneously. Tagging and marking spring fingerling Chinook salmon accounts for most of the equipment demand in Proposal 1 because there is only a short 45 day time period when Chinook salmon are large enough ( mm) to be processed by the SCT6 and because Chinook salmon account for 56% of all salmonines stocked annually. 15