CATCH-AT-AGE ANALYSIS FOR PACIFIC SARDINE (SARDINOPS SAGAX), 1983-1 995

We used CANSAR (Catch-at-age ANalysis for SARdine, an age-structured stock-assessment model) and a wide range of data to estimate bioniass and recruitnient of Pacific sardine (Savdinops sagax) off California and northern Baja California during 1983-95. Daily egg production method (DEPM) spawning bioniass estimates and an abundance index from CalCOFI data based on generalized additive niodels were iniportant new sources of information. Biomass (344,000 MT of sardine age 1+ during July 1995, CV = 33%) increased by 28% year-’. Fishing mortality (particularly for older ages) after 1991 was high and probably not sustainable under average environmental conditions. DEPM data for sardine during 1986-88 and 1994 niay have underestimated spawning bioniass due to incomplete coverage 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 and northern anchovy (Engraulis rnovdax), we make suggestions about how DEPM data should be used for fish stock assessment and fishery management. Size-at-age declined during 1983-95 and was significantly correlated with sardine biomass.