Spawning biomass of Pacific sardine (Sardinops sagax) estimated from the daily egg production method off California in 2013

"The 2013 daily egg production method (DEPM) survey was conducted within standard DEPM area (i.e., in the California Cooperative Fisheries Investigation, CalCOFI, sampling grid lines 60.0 - 95.0), encompassing the spawning core area of Pacific sardine off California from north of San Francisco to San Diego. The spawning biomass of the Pacific sardine (Sardinops sagax) in April 2013 was estimated from the DEPM based on two methods: 1) the traditional method where the egg production ( P 0 ) 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 144,880 mt (CV = 0.36) and 141,002 mt (CV = 0.34), respectively, within a total survey area of 141,397 km 2 (CalCOFI lines 63.3 - 91.7). The daily egg production estimate ( P 0 , an average weighted by area) was 1.34/.05m 2 (CV = 0.299). The estimates of female spawning biomass calculated by the two methods were 84,972 (CV = 0.33) and 82,182 mt (CV = 0.30), respectively"--Executive summary. Emmanis Dorval, Beverly J. Macewicz, David A. Griffith, Nancy C.H. Lo and Yuhong Gu. "August 2014." System requirements: Adobe Acrobat Reader. Includes bibliographical references (pages 17-20).