Information on the abundance and distribution of most Pacific Coast groundfish is obtained principally by bottom trawl surveys. The annual bottom trawl survey in this region is conducted by the NMFS Northwest Fisheries Science Center from four chartered fishing vessels that each conduct over 150 trawls during early summer to early autumn, and cover trawlable habitats from the U.S.–Canada to the U.S.–Mexico borders, at depths of 55 m to 1,280 m. This document covers the history of this survey, including descriptions of predecessor surveys in the region, statistical design, and survey protocols.
