The jack mackerel, Trachurus symmetricus, resource off thewest coast of North America is known to be large and widelydistributed. The spawning biomass is estimated to be 2.1 to 4.8 million tons based upon abundance of jack mackerel eggs collected at sea. The distribution extends from the Gulf of Alaska to the Gulf of Tehuantepec, off the coast of southern Mexico, and as far as 1,500 miles seaward. Within this range lies an area of maximum density which extends from Point Conception to central Baja California.Jack mackerel biological data has not been processed veryrapidly due to higher priorities for analysis of sardine andPacific mackerel data, and the apparent healthy condition ofthis resource. The California Department of Fish and Gameinitiated several projects in 1972 to resolve unanswered biological questions. (14pp.)