Evaluating the Species Selectivity of 8- and 9-Inch Mesh Set Gillnets: A 1988 Test Fishery in the John Day Reservoir of the Columbia River
The Columbia River Basin once supported the largest population of Chinook salmon, Oncorhynchus tshawytscha (Walbaum), in the world (Fulton 1968). Based on early harvest records, estimates have been made of annual runs averaging over nine million fish (Northwest Power Planning Council [NPPC], 1986). In recent years (1978-1987), runs have averaged only about 660,000 fish, with a majority of these being hatchery produced (Bohn and McIssac 1988). Biologists recognize three races (spring, summer, and fall) and two major geographic groupings of Chinook salmon in the Columbia Basin. These geographic groups are know as upriver, composed of fish originating upstream of Bonneville Dam (river km 225), and lower river, composed of fish originating downstream of Bonneville Dam. Historically one of the most important Columbia Basin salmon to Indian tribes and early white settlers of the region, upriver spring Chinook salmon runs once may have averages nearly two million fish per year (NPPC 1985). A ten-year average for this population in recent years (1978-1987) indication a present population size of only about 81,000 fish per year (Bohn and McIssac 1988).
Lumley, B.P., and H. Schaller. 1988. Evaluating The Species Selectivity Of 8- AND 9-Inch Mesh Set Gillnets: A 1988 Test Fishery In The John Day Reservior Of The Columbia River. Columbia River Inter-Tribal Fish Commission Technical Report 89-4. Portland, Oregon.