California Department of Fish and Game, Marine Region
Abstract
Based on the projected Pacific mackerel biomass estimate of 132,500 tons for July 1, 1998, the commercial fishery quota for the 1998/99 fishing season was recommended and set at
33,700 short tons. The 1998 biomass was estimated using output from a stock assessment computer model called ADEPT and certain assumptions about fishing mortality during the first half of 1998. Several important changes were made to improve our assessment during 1998. The assessment model was changed from a quarterly to an annual one and now covers sixty-nine years of fishery data. New indices of relative abundance were added to the analysis to account for changes in mackerel biomass off central and northern California. The July 1, 1998, biomass estimate is slightly higher than last year's CDFG estimate of 101,000 tons for 1997. This year's
results indicate there were more fish in the older year classes than previously estimated. (62pp.
