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Monitoring watersheds for salmonids

We are intensively monitoring various watersheds across the state to evaluate whether restoration activities increase salmon and steelhead production.

Understanding the cumulative effects of local habitat projects on the life cycle of anadromous salmonids, which spawn in freshwater then return to the ocean, requires a carefully selected study design and a long-term investment in research.

How fish respond to restoration efforts can be difficult to isolate. Restoration projects typically happen as localized projects in large watersheds, where many additional factors contribute to interannual variation in salmon abundance. An intensive approach helps us to better understand how fish in restored streams respond relative to other nearby, unrestored streams.

We have been studying four stream complexes since 2004.

Effectiveness studies for restoration projects

Stream with leafless trees on the bank and a pile of large woody debris to the left.

Large woody debris added to stream to improve salmon habitat.

The Intensively Monitored Watersheds (IMW) program evaluates whether restoration activities increase salmon and steelhead production.

The Washington Comprehensive Monitoring Strategy and Action Plan for Watershed Health and Salmon Recovery outlines the rationale and need for the IMW program.

Careful study design
for long-term research

A group of state, federal, tribal, and industry scientists selected four locations in Western Washington for inclusion in the collaborative IMW research program in 2004. Watersheds selected for this program had a history of fish-monitoring data and were small enough that scientists anticipated restoration actions of sufficient scale could be completed to cause a population response.

The "Surfboard" funds four studies

Five fish swim along the bottom of a rocky stream.

Each group of streams is called a "complex." The Salmon Recovery Funding Board or SRFB (often called the "Surfboard") funded studies of four IMW complexes in Western Washington. Three of these, the Strait of Juan de Fuca, Hood Canal, and Lower Columbia River IMW complexes are focused on the effects of freshwater habitat restoration on coho salmon and steelhead trout. The fourth, Skagit River Estuary IMW complex, evaluates the effects of the restoration of inter-tidal and nearshore estuary habitat on Chinook salmon growth and survival.

The scientists selected a Before-After Control-Impact study design to maximize the ability to detect changes in salmon production as a result of habitat-restoration treatments, while minimizing the probability of detecting spurious inter-annual effects.

Intensively Monitored Watershed study publications are kept at the Recreation and Conservation Office. Updated study plans can be found there.