CLIMATE AND EXCEPTIONAL FISH PRODUCTION OFF THE WEST-COAST OF NORTH-AMERICA

From 1976 to 1978 there was a change in the climate over the North Pac ific Ocean. The Aleutian Low intensified and there was a warming of th e sea surface adjacent to North America and a cooling offshore. Associ ated with this change was a period of exceptional fish production. Str ong year classes and above-average survival occurred for many commerci ally important species all along the west coast of Canada and the Unit ed States. Trends in total salmon catches increased primarily from inc reased salmon production in Alaska. Some stocks of maturing pink (Onco rhynchus gorbuscha), coho (O. kisutch), and chinook salmon (O. tshawyt scha) also had above-average growth in 1977. A majority of commerciall y important nonsalmon species that spawned from California to the Beri ng Sea and have a wide range of life history types also had exceptiona lly strong year classes from 1976 to 1978. The exceptional survival ap pears to be related to improved ocean productivity caused by changes i n the intensity of the Aleutian Low.