FOR IMMEDIATE RELEASE: (12/3/97)

SCIENTISTS LOOK AT EAR BONES IN HUNT FOR CHINOOK STRAYS

MARYSVILLE (12/3/97) -- Combing the Snohomish river system the last two autumns, the Tulalip Tribes are on the look-out for stray chinook.

The tribe wants to know if there is legitimacy to concerns that hatchery fish may sometimes stray into natural spawning areas and intermingle with a river system's native runs, thereby affecting the assessment of wild run sizes and possibly genetic makeup. Little hard data exists to show the extent to which this may be a problem.

"People are making a lot of assumptions about hatchery fish straying into natural areas. We thought we'd better get some hard data rather than relying on speculation," said Kit Rawson, Tulalip harvest management biologist.

By collecting the ear bones of spawned out chinook carcasses, the Tulalip Natural Resources Department and the state Department of Fish and Wildlife expect they'll soon learn if any hatchery-produced fish are straying into the river system to spawn naturally. The samples are sent to a state laboratory in Olympia for analysis, but the results aren't expected back until February.

The research will also be important to calculating escapement levels (the number of fish allowed to return and perpetuate the run) of naturally-produced chinook, so that fish managers can develop an effective recovery plan in the event chinook stocks are included in Endangered Species Act (ESA) listings. Puget Sound wild chinook are among salmon species under "extinction-risk" review and could join the list as early as January.

"This will give us a better assessment of the escapement of naturally-produced fish so we can put together the best possible recovery plan if we get an ESA listing, which is very likely," Rawson said.

Tribal and state fisheries technicians collect the ear bones, or otoliths, because the otoliths on chinook originating at Tulalip Hatchery or the state's Wallace River Hatchery are mass marked. The hatcheries use dramatic changes in incubation water temperature, which place discernable marks on the otoliths of developing embryos. Something like fingerprints, the otolith marks are permanent and laboratory analysis can distinguish individual hatchery stocks.

The research project is part of balancing the tribe's goal of restoring wild runs with its desire to produce and catch hatchery fish. Due to dramatic declines in stock productivity, the allowable harvest rates on natural stocks have dropped to the point where the Tulalip fisheries department keeps most of the tribe's usual and accustomed fishing area closed to salmon fishing. As partial compensation for the loss of fishing opportunity the tribe operates the hatchery, which releases about 1.5 million chinook salmon fingerlings per year into Tulalip Bay. The returning adults contribute to treaty and non-treaty commercial harvests, as well as a popular Tulalip Bay recreational fishery.

"We want to protect wild chinook stocks while continuing to responsibly produce fish for harvest from our hatchery," Rawson said.

Mass marking of hatchery chinook at the Tulalip and Wallace River hatcheries began with fish spawned in 1993. Otolith sampling of chinook carcasses in the river system began in 1996, but 1997 comprised the first return of the four-year-old adults that make up most of the chinook run. Along with in-river samples, Tulalip sampled its terminal area fishery (Area 8D) in Tulalip Bay for otoliths in 1997. Technicians are also sampling hatchery fish to see whether naturally-produced fish are returning to the hatcheries.

The tribe secured funding for the research project from a National Oceanic and Atmospheric Administration grant and from Pacific Salmon Treaty money available through the United States Department of Interior.

FOR MORE INFORMATION, PLEASE CONTACT: Kit Rawson, Tulalip Harvest Management Biologist, (360) 651-4478; Logan Harris, North Sound Information Officer, Northwest Indian Fisheries Commission, (360) 424-8226.