Study to examine steelhead interbreeding

By Allen Thomas, Columbian outdoors reporter

Published:

 

Five Southwest Washington watersheds will be studied in the coming year to learn how much interbreeding is occurring between hatchery and wild steelhead.

Bryce Glaser of the Washington Department of Fish and Wildlife said the agency has $375,000 budgeted to complete the initial phase of this research by fall of 2015.

The money comes from a federal grant designed to address key questions associated with monitoring wild salmon and steelhead populations.

A similar study is being planned for Puget Sound rivers.

Local waters proposed for study include the East Fork of the Lewis, Wind, Kalama, Coweeman and Elochoman rivers.

Thomas Buehrens, a department research scientist, said the watersheds were selected because of their differences.

Some have just winter steelhead, or just summer steelhead, while others have both races.

The five also have differences in hatchery facilities and some receive large releases of hatchery steelhead, while others get small numbers.

The Wind River has not been stocked with hatchery steelhead since the late 1990s and will serve as a control stream, Buehrens said.

Washington’s Statewide Steelhead Management Plan, adopted in 2008, places its highest priority on protecting wild stocks.

The plan specifies limits on interbreeding between hatchery and wild fish.

Buehrens said there is a lot of research that shows when wild and hatchery fish interbreed the off-spring do not survive as well as pure wild fish.

But the agency needs additional data to determine if its conservation objectives are being met.

Tissue samples are needed for the research. The department has a considerable number of samples and can get more from steelhead captured in weirs, traps, hatcheries and by hook-and-line.

All ages of steelhead are needed, including young rearing in the rivers and those ready to migrate to the ocean. Two to four technicians will work two months electroshocking to collect additional samples.

Much of the expense is testing the samples, which costs about $43 per fish.

Details of the research were presented to the Steelhead Management Working Group, 20 volunteers who have been meeting with the department since September regarding the Lewis, Washougal and Salmon Creek watersheds.

The group has recommended the East Fork of the Lewis River become a wild gene bank and releases of hatchery-origin winter and summer steelhead be discontinued.

The state steelhead plan calls for establishment of a network of wild gene banks across Washington.

Work Group members also are discussing the future of hatchery programs in the Washougal and Lewis rivers.

The hatcheries mostly use a winter steelhead brood stock that originated from Chambers Creek, a Puget Sound tributary, and a summer steelhead brood stock which originated from the Washougal and Klickitat rivers.

During the last decade, there has been a push to shift hatcheries to using wild brood stock. However, studies in recent years have shown down sides in using wild brood stock.

Buehrens said the offspring of wild brood stock residualize (where the young do not migrate to the ocean) more than a traditional hatchery fish.

They also are harder to grow to the desired size in hatcheries.

Adult winter steelhead from wild brood stock programs tend to return over a longer time frame and are believed to bite better, both pluses for sportsmen.

The working group will continue the discussion on hatchery spawning stocks along with potential angling regulations for the Lewis and Washougal rivers plus Salmon Creek when it meets at 1 p.m. Friday at the Washington Department of Fish and Wildlife, 2108 Grand Blvd.