Spawning Biomass of Pacific Sardine (Sardinops sagax) Off U.S. in 2012.

摘要

The spawning biomass of the Pacific sardine (Sardinops sagax) in April 2012 was estimated using the daily egg production method (DEPM) calculated by two methods: 1) the traditional method where the egg production (P0) was a weighted mean while each adult parameter was an unstratified estimate, and 2) a stratified procedure where the estimate of total spawning biomass is the sum of the estimated spawning biomass in each of two regions representing high and low spawning activity. The two estimates of the spawning biomass were 282,110 mt (CV = 0.43) and 255,391 mt (CV = 0.32), respectively, for the standard DEPM survey area of 270,991 km2 off the west coast of North America from north of San Francisco to San Diego, California, California (CalCOFI line 60.0-95.0). The daily egg production estimate (P0, an average weighted by area) was 0.84/.05m2 (CV = 0.27). In the standard DEPM area, the estimates of female spawning biomass calculated by the two methods were 120,902 mt (CV = 0.36) and 113,178 mt (CV = 0.27), respectively. Samples taken north of CalCOFI line 60 found no eggs in either CalVET tows or CUFES collections, and one trawl out of three caught sardines north of CalCOFI line 60 during the R/V Ocean Starr cruise. Hence, coastwide estimates of sardine spawning biomass and female spawning biomass were not calculated.