PROGRAM: Hatchery-Wild Salmon Interactions

PROGRAM

Hatchery-Wild Salmon Interactions

Note: For more information on our current research, please refer to the ADF&G website. For up-to-date catch information, please go to our blog.

Overview

In Prince William Sound, wild and hatchery-bred pink and chum salmon are important commercial fisheries. Pink salmon is the largest of any commercial fishery and is serviced primarily by the purse seine fishery.

Commercial, recreational and subsistence harvests of salmon profoundly affect the economic and cultural fabric of Prince William Sound communities. Coho, sockeye, Chinook, pink, and chum salmon support valuable fisheries in the region. The economic impact of these fisheries is critical to many small coastal communities here, and around the globe. Yet, the interactions between wild and hatchery fish are little understood.

Our research focuses primarily on two species of Pacific salmon found in Alaska, both of which evolved from their ancient rainbow trout ancestors. They start their lives as freshwater fish, then change and develop the ability to live and grow in the ocean where they mature. As native fish evolve and interact with hatchery fish, there are inevitable impacts. We seek to understand those impacts in order to help maintain the unique identity and health of every species.

Today, the Prince William Sound Science Center is in its second year of  a major contract from the Alaska Department of Fish and Game (ADFG) for a 4-year study entitled “Interactions of Wild and Hatchery Pink and Chum Salmon in Prince William Sound and Southeast Alaska.” The overarching questions that are being be addressed for the State of Alaska are:

(1) What is the extent and annual variability in straying of hatchery pink salmon in Prince William Sound (PWS) and chum salmon in PWS and Southeast Alaska (SEAK)?

(2) What is the impact on fitness (productivity) of wild pink and chum salmon stocks due to straying of hatchery pink and chum salmon in PWS and SEAK, respectively?

The PWSSC is engaged primarily in collecting the large amounts of field data to support scientific analyses to answer these questions. The study was designed, and continues to be guided, by a Science Panel organized by ADFG consisting of state, federal, NGO, and academic experts on salmon biology and management, genetics, hatchery issues, and experimental statistics.

The contract study is organized into three projects: PWS stream sampling (Dr. Kristen Gorman, Project Leader); PWS ocean sampling (Dr. Michele Buckhorn, Project Leader); Southeast Alaska stream sampling (Tory O’Connell, Project Leader). The Southeast Alaska stream sampling project is being subcontracted to the Sitka Sound Science Center. Dr. Eric Knudsen is the overall project manager and science coordinator, working under contract to the PWSSC.

Some preliminary field work started in 2012 to test some field methods, but the larger effort is now underway and will continue through 2016. To achieve the scientific objectives, adult salmon are being sampled in about 65 streams three to 18 times (depending on stream significance) in each spawning season and nine standard offshore PWS fishing sites are being sampled with a gill net twice weekly from mid-May through early September. Bone and tissue samples will be collected from adult fish to identify their hatchery-wild origins and, in a subset of streams, their DNA signatures. The streams sampled for adult DNA will be re-sampled for their offspring alevin DNA in the spring to determine the relative reproductive success of the genetically identified hatchery and wild offspring.

Results from this study will help ADFG salmon managers make informed decisions about hatchery and wild salmon management.

For more information, please refer to the ADF&G website.