Planning Tools for Recovery: Columbia River Basin examples

Tom Cooney Northwest Fisheries Science Center of NOAA Fisheries

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Life cycle models of salmon populations or population aggregates have been used in research, stock status assessment and management in the Columbia River Basin for some time. Variations on simple adult stock recruit models and more complex EDT applications were used as the basis for expressing hypothesized relationships between habitat conditions and life stage survival and capacities in analyses leading to the recovery plans in place for the Upper Columbia and Mid-Columbia DPSs. Those models were expressed in a life cycle framework that also incorporated assumptions regarding the impacts of hydropower, hatchery and harvest scenarios. It is critical to recognize that applying life cycle based models to particular populations or production areas requires a separate assessment of current habitat conditions and a specific analysis of how habitat conditions would likely respond to restoration and/or protection actions.

A set of stage structured models linked directly to empirical estimates of spawner to smolt and smolt to adult return data sets and incorporating alternative ocean climate scenarios were used to inform the development of the 2008 Federal Columbia River Hydropower System Biological Opinion. Models were developed for six different populations, four were chinook salmon and two steelhead. One of the steelhead models represented the core area of a ICTRT defined population (the Umatilla River), other modeled natural production from a subarea within the Little Salmon River population.

The FCRPS Biological Opinion was augmented with an Adaptive Management Implementation Plan (AMIP) in 2010. The AMIP called for expanded life cycle models to support conservation planning and implementation. Project objectives include expanding the models to additional populations, accommodating alternative assumptions regarding freshwater and ocean climate scenarios, hatchery effects, effects of tributary habitat actions, and potential hydropower system contingencies, The project is organized around regional modeling groups to encourage sharing of concepts and the coordinated development of functional relationships. The Umatilla and Rapid River stage based models have been updated and the model format has been applied to four more populations (all in the Yakima River major population group) and one additional Snake River population subsection (Potlatch Creek).

Life cycle models with expanded linkages to freshwater habitat conditions are generally further along for chinook in contrast to steelhead, applications have been developed for Chinook salmon populations in the Grande Ronde River basin and the Upper Columbia River. Functional relationships between stream temperature flow and juvenile survival have been incorporated into life cycle models for 14 Salmon River Chinook salmon populations. Some of these habitat condition relationships may be applicable to o. mykiss juvenile production as well. A model framework developed under the Integrated Status and Trends Monitoring Program (ISEMP) has been applied to data from the Lemhi River and applications to South Fork Salmon River chinook populations are under development. That particular application focuses on estimating the potential response to ongoing efforts to reconnect tributary production areas in the Lemhi drainage and it is designed as part of an adaptive monitoring and evaluation program. A dynamic modeling approach centered on a food web framework is being pursued for the Methow River basin using field data for both chinook and o. mykiss. Life cycle models for steelhead have been expanded to additional populations.

Work is underway to incorporate interactions with co-occurring resident O. mykiss into population models. That work builds on models developed for sections of the Yakima River drainage that have contrasting habitat conditions with respect to supporting anadromous and resident life history patterns. A meta-analysis of supplementation effects on natural production functions across Interior stream type Chinook populations has been completed. Regional population modeling groups are expanding models to accommodate alternative assumptions regarding interactions with hatchery supplementation programs. Under development are additional ocean climate and scenarios and the capability for modeling alternative assumptions for hydropower system survival relationships.