Historical Steelhead & Coho Salmon Recovery: Trapping and Releasing in Mount St. Helens Tributaries

The Washington Department of Fish and Wildlife (WDFW) and federal partners have utilized trapping and releasing steelhead and coho salmon in tributaries near Mount St. Helens to restore fish populations. These efforts target smaller streams to bypass habitat barriers created by the 1980 eruption, according to agency recovery records as of June 16, 2026.

The program focuses on moving salmonids into headwater streams where they can spawn without the interference of volcanic debris. This active management is part of a broader resource recovery strategy to rebuild the biological assets of the Toutle River basin and surrounding watersheds.

How is the trap-and-release program implemented?

Biologists use specialized traps to capture migrating steelhead and coho salmon in the lower reaches of the tributaries. Once captured, the fish are transported in oxygenated tanks to higher elevations. This process allows the fish to bypass sediment dams and debris flows that have blocked natural migration paths since the 1980 volcanic event.

The process is grueling. Biologists transport the fish in oxygenated tanks across rugged terrain to ensure they reach the upper reaches of the tributaries where spawning is possible.

According to WDFW operational guidelines, this method prevents the “bottlenecking” of populations in the lower river, where fish are more susceptible to predation and temperature stress. By distributing the fish across a wider range of smaller tributaries, the agencies increase the probability of successful spawning and juvenile survival.

Which agencies fund and manage the recovery efforts?

The recovery is a multi-agency operation involving state and federal resource management budgets. The primary entities involved include:

• The Washington Department of Fish and Wildlife (WDFW), which handles on-the-ground trapping and biological monitoring.
• NOAA Fisheries, which provides federal oversight and funding for the recovery of species listed under the Endangered Species Act.
• The U.S. Forest Service, which manages the Mount St. Helens National Volcanic Monument and coordinates land access for recovery teams.

These agencies operate under a shared mandate to restore the ecosystem’s productivity. Funding is typically allocated through federal grants and state wildlife budgets dedicated to habitat restoration and species recovery.

What is the economic impact of salmon restoration?

Restoring salmon populations serves both ecological and economic functions. Steelhead and coho salmon are primary drivers of the regional recreational fishing economy. The return of these species to the Mount St. Helens region increases the viability of local guiding services and tourism.

From a resource management perspective, the “trap and release” strategy is a high-cost, high-intervention approach. It differs significantly from passive habitat restoration, which involves removing barriers to allow fish to migrate on their own.

While habitat restoration is more sustainable over decades, trapping and releasing provides an immediate population boost. This is necessary in areas where volcanic sediment makes natural barrier removal technically impossible or prohibitively expensive.

How does this compare to previous recovery methods?

Early recovery efforts following the 1980 eruption focused primarily on the main stems of the rivers. However, data from the WDFW indicated that main-stem recovery was insufficient to maintain genetic diversity. The shift toward smaller tributaries represents a strategic change in how the state manages volcanic recovery zones.

By targeting smaller tributaries, managers are creating “satellite” populations. If a landslide or flood destroys one tributary’s spawning grounds, the other populations remain intact. This diversification reduces the risk of total population collapse in the event of another geological disturbance.

According to NOAA Fisheries, this spatial distribution is a key component of long-term resilience planning for Pacific Northwest salmonids.

The success of these programs is measured by the count of returning adults in subsequent years. Biologists monitor these returns to determine if the investment in trapping and transporting fish results in a self-sustaining population.