Growth Rate Modulation in spring Chinook salmon supplementation
Statement of Work and Budget FY2006

A major focus of current actions under Northwest Power and Conservation Council (NWPCC) and Bonneville Power Administration (BPA) programs is the support of 12 supplementation programs to assist in recovery of 8 ESUs of Chinook salmon and steelhead trout listed as threatened or endangered under the ESA.   A significant concern for these programs is that they release fish that are ecologically, genetically, and phenotypically similar to their wild cohorts.  In response to this concern, a number of rearing guidelines for supplementation programs have been made in the Artificial Production Review and Evaluation report (APRE).  
Under the initial portion of this project (Growth modulation in salmon supplementation, BPA # 200203100) we have undertaken perhaps the most extensive evaluation of a supplementation program with regard to these APRE rearing guidelines.  We have found that spring Chinook salmon released from the Yakima River spring Chinook salmon supplementation program differ substantially from wild spring Chinook salmon in the same river, even though fish released from this program originate from Wild Yakima River spring Chinook salmon broodstock.  Specifically, 20-50% of putative male smolts were actually destined to mature at age 2, a proportion 2-5-fold greater than we have found in wild fish in the Yakima River (Larsen et al. 2004).  This relatively high rate of early male maturation represents a direct loss of potentially returning anadromous adults.  These early maturing males also introduce a novel ecological presence into the Yakima and Columbia River as they residualize over the summer rather than migrating to the ocean.  Perhaps of greater significance, the majority of these males appear to be lost from the breeding population, since few early maturing males of hatchery origin are found near the redds of spawning adult anadromous fish.  If no early maturing males successfully breed, a potentially potent artificial selection regime is set-up because there is a well-documented relationship between growth and early maturation of males and almost all fast-growing juvenile males could be lost as potential breeders.  Finally, the production of high proportions of early maturing males may result in altered gender ratios on spawning grounds when anadromous adults return.  We have found out-migrating hatchery smolts are biased towards females (55 - 70% 02 - 05) (Larsen et al. 2005).  Studies, to date, demonstrate that hatchery growth profiles are not well matched to that of wild fish, suggesting that hatchery rearing practices are a key component of the altered life-history pattern we have observed (Larsen et al. in press).  
We suggest that the Yakima Program is not novel with regard to the presence of high rates of precocious male maturation; rather, it is novel in actually assessing its' program with regard to APRE standards.  Preliminary data, based upon PIT-tag detections of age 2 maturing males in ladders at Columbia River dams, suggests early male maturation is wide-spread in supplementation programs in the Columbia River Basin (Beckman and Larsen 2005).  Based upon these findings the central objectives of this statement of work are the following:
1). Continue monitoring growth and life-history variation among wild Yakima River juvenile Chinook salmon to continue building a wild-fish template for the rearing of fish in the Yakima River Supplementation Program and other spring Chinook salmon supplementation programs in the Basin.
2). Continue monitoring fish produced in the supplementation program to assess how changing hatchery practices (ponding date, growth rate, release strategy) affect early male maturation.
3). Continue to explore how environmental variation (temperature, feeding rate, emergence timing) affects the expression of early male maturation and other significant life-history traits in controlled laboratory experiments, to further develop fundamental biological information regarding factors modulating life-history expression in Chinook salmon.
4) Expand our efforts to assess early male maturation and altered life-history patterns in other hatchery programs in the Columbia River Basin.

Taken together the work put forth by this statement of work will address these objectives by continuing to monitor the extent of this problem at both the Yakima and Columbia Basin wide level, design rearing strategies for use in salmon hatcheries throughout the basin and test the success of implementation of these innovative technologies at the hatchery production scale.

There are two contracts (University of Washington and NOAA ) under this project.  There are many duties associated with this project that are shared between the two contracts and they are noted in the description for specific work elements. In general, the University of Washington contract is associated with data collection, fish rearing, maintaining hatchery, and laboratory sample analysis and the NOAA contract is used for work elements associated with permit preparation, experimental design, collaborator coordination, fish rearing and maintaining hatchery also, contract reporting, data collection, interpretation, analysis, and peer reviewed publication and presentation of results to the scientific community.

References
Larsen, D.A., Beckman, B.R., Strom, C.R., Parkins, P.J., Cooper, K.A., Fast, D.E., and Dickhoff, W.W.  (In press). Growth modulation alters the incidence of early male maturation and physiological development of hatchery reared spring Chinook salmon: a comparison with wild fish.  Transactions of the American Fisheries Society.
Beckman, B.R. and Larsen D.A.  (2005). Up-stream migration of minijack (age-2) Chinook salmon in the Columbia River:  behavior, abundance, distribution, and origin Transactions of the American Fisheries Society 134:1520-1541.
Larsen, D.A., Beckman, B.R., Strom, C., Parkins, P., Cooper, K.A., Johnston, M., Fast, D., and Dickhoff, W.W.  (2005).  Growth rate modulation in spring Chinook salmon supplementation.  U.S. Department of Energy, Bonneville Power Administration (BPA Report DOE/BP-00017450-1)  49pp.
Larsen, D.A., Beckman, B.R., Cooper, K.A., Barrett, D., Johnston, M., Swanson, P., and Dickhoff, W.W.  (2004).  Assessment of high rates of precocious male maturation in a spring Chinook salmon supplementation hatchery program.  Transactions of the American Fisheries Society.  133, 98-120.