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About SPU
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Water System
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Habitat Conservation Plan--HCP
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Sockeye Hatchery
Goals & Concepts
An innovative approach is being taken for the development of the new sockeye hatchery. This hatchery and associated program are being developed as an integrated package to ensure that the design and operations work together to maximize the chances of successfully meeting project goals (see below).
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The program includes a long-term commitment to monitoring and adaptive management (see below) to ensure that results of the project will be forthcoming and will allow operations to be modified if needed.
The project goals are:
- • Implement a biologically and environmentally sound long-term hatchery program that will help to provide for the recovery and persistence of a well-adapted, genetically diverse, healthy, harvestable population of sockeye in the Cedar River.
- • Avoid or minimize detrimental effects on the reproductive fitness and genetic diversity of naturally reproducing salmon populations in the Cedar River and the Lake Washington Basin.
- • Gather new information over the life of the project by monitoring the performance and effects of the hatchery program and use this information as the basis for evaluating and modifying operations, when necessary, to meet program objectives.
- • Satisfy any mitigation obligations the City may have for the sockeye migration blockage created by the Landsburg Diversion Dam as defined in the Landsburg Mitigation Agreement, state and federal law and pursuant to City ordinance and initiatives.
A fundamental concept associated with this hatchery program is that a composite stock of sockeye is maintained in the Cedar River; that is, one that is influenced by the hatchery as well as by natural selection pressures. To realize the full productivity of the Cedar system (hatchery and natural), this composite stock needs to continue to have a high level of reproductive fitness when spawning naturally. Projections indicate that relatively few hatchery origin spawners will be needed to provide eggs for each successive generation. Most hatchery returns are expected to spawn naturally. Thus, sockeye, irrespective of whether they were produced naturally or in the hatchery, need to be able to spawn successfully in the wild, if fry production is to be high enough to generate the numbers of adults that are needed to meet spawning goals and provide fishing opportunity. Neither natural nor hatchery fry production alone is likely to be sufficient to produce sufficient adults to provide fishing opportunity in many years.
By selecting a random group from the adult returns to the Cedar River to use for spawning, wild origin sockeye will be used along with hatchery-origin sockeye for broodstock. Since certain selection pressures that occur during natural spawning can not be replicated in the hatchery (mate selection, redd site selection) this program relies on using broodstock that includes fish that are periodically subjected to these pressures. This is done to help maintain reproductive fitness.
Finally, wild fry production is influenced by the numbers of adults returning to spawn in the Cedar River, the reproductive fitness of these fish, and, importantly, by the conditions in which they incubate. Current confined conditions in much of the Cedar River create velocities during higher flows that cause scour of the streambed and result in mortality of incubating eggs. Improvements to habitat resulting in a reduction in the risk of redd scour will improve the survival of sockeye and other species during incubation and contribute to the likelihood that salmon returns will improve. Thus, habitat improvement and the hatchery program can work together to increase adult returns and the potential for fisheries to occur, as well as to help to maintain high reproductive fitness of the composite stock.
Related links
Sockeye Mitigation
Habitat Conservation Plan- HCP
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