Artificial propagation is used extensively as a management tool for salmon and steelhead in the Columbia River Basin. Hatchery programs are operated to contribute to two principal management goals:
- Harvest Augmentation: to provide fish for tribal, commercial, and recreational harvest while keeping impacts to natural populations within acceptable limits.
- Supplementation: the use of hatchery fish to enhance the viability of natural populations while keeping impacts to non-target populations within acceptable limits.
Although hatcheries have been used for nearly a century, considerable uncertainty remains as to the overall benefits and risks of artificial propagation programs. Many questions critical to the evaluation of hatchery management can likely be addressed through individual hatchery program research, monitoring and evaluation (RME) plans. However, key questions regarding the effectiveness of hatcheries as a class of actions are unlikely to be adequately addressed by current RME when hatchery programs are viewed as separate entities. These broader hatchery effectiveness questions relate to:
- the ability of hatchery programs to achieve regional species harvest and/or conservation objectives; and
- the short and long-term effects of hatchery programs on the productivity of target and non-target fish populations.
Developing a better understanding of the broader impacts of hatcheries will require long-term, integrated RME involving the use of combined data across individual hatchery programs. It will also likely require the development of stratified and representative study designs and associated analyses spanning large geographic areas. In this regard, two key broad-scale hatchery program effectiveness questions are the current focus of CSMEP designs, and analyses to date have focused on the identification of appropriate strata and the spatial / temporal response designs to address these questions:
- What is the magnitude and distribution of adults from harvest augmentation and supplementation hatcheries?
While existing individual hatchery RME can generate information on stray rates, they are unlikely to adequately estimate the proportion of non-targeted populations that are composed of strays (a critical element of evaluating hatchery impacts).
- What is the relative reproductive success of hatchery and natural origin adults under natural conditions?
While current RME can evaluate the relative reproductive success of hatchery origin adults for some individual hatchery programs, it is unclear whether existing RME efforts effectively represent the broad diversity of hatchery types currently in operation.