Fishery Sampling at Tulalip

As part of the tribes' comanagement responsibility, Tulalip Fisheries conducts routine sampling of fish harvested by Tulalip tribal members and fish returning to the Tulalip Hatchery. A portion of each week's harvest is sampled to record biological characteristics, such as weight, length, sex, and age. The age of the fish is determined from the circuli, or growth rings, found on scales taken from near the lateral line of the fish. We take scales from chinook salmon, chum salmon, and steelhead trout. Scales are not collected for age determination from coho salmon or pink salmon since these species mature at a single age. Currently, our scale collections are sent to the Washington Department of Fish and Wildlife (WDFW) scale reading laboratory in Olympia where age determinations are made and the results are recorded into a joint state/tribal database along with the data collected by samplers from other tribes and WDFW.

Another important component of fishery sampling involves determining the mix of stock origins in any given catch. We use a variety of techniques for stock composition, depending upon the particular species and other factors. Tulalip participates in the coast-wide coded-wire tag program for stock composition analysis of chinook and coho salmon. In addition, we have mass-marked all chinook salmon from the Tulalip Hatchery and the nearby Wallace River Hatchery (operated by WDFW) using thermal variation of incubation water to create idetifiable patterns on the otoliths of developing embryos. Beginning with the 1997 season, we will be sampling our chinook salmon fisheries for otolith marks so that we can determine the hatchery versus wild stock contribution to these important tribal fisheries. We also use genetic stock identification (GSI) to estimate stock composition in our chum salmon fisheries. Tulalip is responsible for GSI sampling of chum salmon fisheries in this area, the results of which contribute to analysis of chum salmon stock composition throughout Puget Sound. In addition, we have genetically marked all chum salmon production from Tulalip Hatchery, and we conduct special sampling in our terminal area fisheries for these mass-marked fish so that we can determine the contribution of wild and hatchery-produced fish to each week's fishery.