Marine resource surveys on the continental shelf off Oregon, 1971-74 : completion report July 1, 1971 to June 30, 1975

Groundfish surveys off Oregon were conducted over a four year period (1971-74)\ud between the Columbia River and Cape Blanco. Primary purpose of the surveys was to obtain estimates of biomass of important groundfish occupying the continental shelf and upper continental slope.\ud \ud Survey design was based on a 5 x 5 N mi grid with a random starting point. This\ud resulted in trawling intensity of about 1 tow per 25 N mi² of trawlable bottom.\ud Samples for age, size and sex composition were taken from important species of flatfish. Weights of all species caught were obtained.\ud \ud Estimates of biomass (a11 species) were 283,750 metric tons in 1971-72 and\ud 235,117 metric tons in 1973-74. Pacific hake was the most abundant species followed by Dover sole. Estimates of potential yield were determined for five species of flatfish. Data indicate that only petrale sole are being fully exploited. Increased yield could be obtained without increasing fishing effort if economic conditions were such that the species caught were more completely utilized.\ud \ud Distribution of major species is depicted by catch maps. Distribution of some species is closely allied with depth and sediment type or both. No attempt was made to quantify species association