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1994 Columbia River Basin Fish and Wildlife Program |
| Council document 94-55 | |
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8.4 Stock Identification
8.4A Expand Genetic Stock Identification Sampling
Fishery Managers
8.4A.1 Develop and implement an expanded genetic stock identification program for monitoring inriver and ocean fisheries as needs are identified. Review the proposed program with the Council by June 30, 1995, prior to implementation.
Bonneville, States and Appropriate Federal Agencies
8.4A.2 Ratepayers, states and the federal government should share the cost on an equal or other mutually agreed basis for expanding the program to achieve the desired level of information needed.
8.4B Improve Genetic Stock Identification Data Base
Fishery Managers
8.4B.1 Determine the need for further development of a genetic stock identification data base for Columbia River stocks. Evaluate the potential for using DNA ?fingerprinting? and other methods to identify chinook, coho, chum, sockeye and steelhead stocks in the Columbia River Basin. Review findings and recommendations with the Council by June 30, 1995.
Bonneville
8.4B.2 Fund the genetic stock identification program upon Council approval.
8.4C Marking Hatchery Salmon
The inability to easily identify hatchery fish exacerbates several problems. For example, concerns have been raised that stray hatchery fish may interbreed with wild and naturally spawning stocks, or with other hatchery stocks, with detrimental genetic impacts. To protect Snake River fall chinook, which have been listed as threatened under the Endangered Species Act, it has been proposed that all fall chinook released from hatcheries with histories of significant straying be marked. In addition, it is not generally possible to distinguish hatchery salmon from wild and naturally spawning salmon in mixed-stock fisheries. Finally, because not all hatchery salmon are marked, data on migration patterns, contribution to fisheries and other biological traits that, if known, could be used to improve survival, are limited.
Marking all hatchery salmon has the potential to help solve these problems, making it possible to identify stray hatchery fish and remove them from wild and naturally spawning populations and from other hatchery brood stocks, to harvest hatchery fish selectively, affording some protection to naturally spawning stocks, and allowing better data to be gathered on characteristics of hatchery stocks. However, some important concerns need to be addressed. For example, marking fish is believed to decrease their survival, perhaps considerably. In addition, conflicts with use of the fin clip to identify coded-wire tagged fish need to be resolved.
Fishery Managers
8.4C.1 Continue to identify and report to the Council concerning hatcheries known to have relatively high rates of straying, whose strays are believed to be a threat to the integrity of wild and naturally spawning or hatchery stocks. Identify, if possible, an acceptable mark for fish from these hatcheries that complements existing marking programs.
Bonneville
8.4C.2 Continue to fund a program to mark all salmon from hatcheries having high stray rates, using the mark determined by fishery management agencies to be acceptable for this purpose, and to evaluate the effectiveness of such marking.
8.4C.3 Fund fishery managers to coordinate with appropriate technical experts to determine the feasibility of marking all hatchery salmon. Scope the marking program and identify alternative uses for the information obtained. The marking program should minimize mortalities caused by marking and meet the following criteria: 1) the mark should be applied without handling individual fish or causing significant stress; 2) the mark should endure throughout the life cycle of the fish; 3) the mark should be readable without killing the fish bearing the mark; and 4) the methods should be inexpensive enough to permit the marking, sampling and processing of a representative sample of recovered marks at a reasonable cost. Conduct this evaluation in conjunction with the evaluation in measure 8.4C.1, above. Specifically, the information should provide answers to questions needed to resolve conflicts between hatchery programs and goals for wild and naturally spawning fish stocks, and improve hatchery fish survival. Report to the Council by February 1, 1995.
8.4C.4 Share funding of externally marking Willamette River spring chinook to allow identification of adults upon return to the Willamette Basin. Such marking will allow differential harvest of underutilized hatchery fish and identification of the current population size of wild and naturally spawning spring chinook in the basin.
Bonneville and Fishery Managers
8.4C.5 Mark all hatchery-reared chinook by 1995 to facilitate selective harvest in the future, pursuant to findings from the marking feasibility called for in 8.4C.3.
8.4D Improve Stock Abundance Prediction Methods
Fishery Managers
8.4D.1 Develop expanded marking and catch sampling programs as required for ocean and inriver fisheries where Columbia River weak stocks are caught. By May 1, 1995, review with the Council the magnitude and cost-effectiveness of any expansion in the existing marking and catch sampling programs prior to implementation.
Bonneville and Appropriate Federal Agencies
8.4D.2 Share the cost on a 50/50 or other mutually agreed basis for expanding marking and sampling programs to improve precision of additional coverage.
Fishery Managers
8.4D.3 Identify and implement research and model refinements needed to improve pre-season and in-season estimates of abundance and fishery impacts. Report on the planned work to the Council by January 1, 1996 prior to implementation.
Bonneville and U.S. Department of Commerce
8.4D.4 Share the cost on a 50/50 or other mutually agreed basis for the needed research and model development to improve accuracy and precision.
8.4E Assess Genetic Implications of Harvest
Harvest strategies affect not only the quantity of salmon reaching the spawning ground, they can also affect the genetic composition of the surviving fish. The age of maturation is inheritable in salmon, and many, if not most, fisheries are size selective, i.e., larger and older fish are targeted. The result is that fewer adults from older age classes will make up the spawning population.
This has two interrelated effects. Not only are some genetic components of the population eliminated through time, but productivity decreases because smaller fish have fewer eggs. Sustainable salmon populations and fisheries require that fishing strategies and escapement objectives provide comprehensive protection to the salmon populations as genetic resources. The fishery managers need to determine how this might be accomplished. In the interim, exploitation rates should be conservative.
Appropriate Federal Agencies
8.4E.1 Fund the necessary studies, including, but not limited to, literature search, simulation modeling, and monitoring and evaluation of proposed fishing strategies, in order to pursue the goal of reducing genetic impacts of harvest.