STATUS OF THE PACIFIC SARDINE (Sardinops sagax) RESOURCE IN 1996

We estimate the biomass of the Pacific sardine (Sardinops saga) population (age one and older) off California and northern Baja California on July 1, 1996 to have been about 5 10,000 short tons (CV 44% and 95% confidence interval from 287,000 to 1,099,000 tons ). Our estimate was based on output from a stock assessment model called CANSAR. For the first time, biomass estimates from CANSAR were compared to biomass estimates from two other stock assessment models (Virtual Population Analysis or VPA and an age structured model without catch at age data). Results from all three models were similar, although there was considerable uncertainty in biomass estimates for recent years. Questions about stock structure and distribution were major sources of uncertainty in our sardine assessment. Recent data show increased sardine abundance in the Pacific Northwest off the Columbia River and as far north as British Columbia, but we were unable to determine if those fish were part of the stock available to the California fishery and whether the biomass of sardine in northern areas was included in estimates from OUT models. Similar questions exist about sardine in Mexican waters south of Ensenada. These problems were confounded by the fact that our survey and fishery data which were mostly collected within the Southern California Bight. We suggest that additional information is needed to resolve these questions because different modeling approaches gave similar results.