CATCH-AT-AGE ANALYSIS FOR PACIFIC SARDINE (SARDINOPS-SAGAX), 1983-1995

We used CANSAR (Catch-at-age ANalysis for SARdine, an age-structured s tock-assessment model) and a wide range of data to estimate biomass an d recruitment of Pacific sardine (Sardinops sagax) off California and northern Baja California during 1983-95. Daily egg production method ( DEPM) spawning biomass estimates and an abundance index from CalCOFI d ata based on generalized additive models were important new sources of information. Biomass (344,000 MT of sardine age 1+ during July 1995, CV = 33%) increased by 28% year(-1). Fishing mortality (particularly f or older ages) after 1991 was high and probably not sustainable under average environmental conditions. DEPM data for sardine during 1986-88 and 1994 may have underestimated spawning biomass due to incomplete c overage of spawning habitat. There was a modest potential for bias in the DEPM data due to nonrepresentative sampling of young age groups by survey gear. On the basis of experience with DEPM data for sardine an d northern anchovy (Engraulis mordax), we make suggestions about how D EPM data should be used for fish stock assessment and fishery manageme nt. Size-at-age declined during 1983-95 and was significantly correlat ed with sardine biomass.