Sardine Egg Distribution Maps and Biomass Surveys

Introduction

Annually, in April, the Fisheries Resources Division carries out an estimate of sardine biomass in U.S. waters using the Daily Egg Production Method (DEPM). The DEPM, used since 1996, employs a continuous underway fish egg sampler (CUFES ), a device that continually collects fish eggs while the ship is under way, and also conventional vertical net tows. Eggs taken in CUFES are counted on board ship at about intervals of 0.5 h or less and the data are transmitted to the FRD and plotted on a survey map. During April, one can follow the development of the egg map by checking this web site periodically, the complete maps generated from past cruises are also shown. For more details regarding the use of CUFES in the DEPM see Lo et. al (2001).

Lo, N.C.H. and B. Macewicz. 2004. "Spawning biomass of Pacific sardine (Sardinops sagax) off California in 2004 and 1995". Southwest Fisheries Science Center Admin. Rep. No. LJ-04-08. 30p.

The daily egg production of Pacific sardine (Sardinops sagax) off California from San Diego to Morro Bay was estimated to be 1.52/0.05 m² (CV = 0.18) and the spawning biomass was estimated to be 485,121 mt (CV=0.36) for an area of 365,906 km2, using the daily specific fecundity (number of eggs/population weight (gm)/day: 22.94 from the 2002 cruise (compared to 23.55 used in the years prior to 2002). The area is slightly larger than 325,082 km2 estimated in 2002. The estimates of spawning biomass of Pacific sardine in 1994 and 1996 - 2003 are 127,000 mt, 83,000 mt, 410,000 mt, 314,000 mt, 282,000 mt, 1.06 million mt, 791,000 mt, 206,000 mt, and 485,000 mt respectively. Therefore, the estimates of spawning biomass have been fluctuated since 1994.

From April CalCOFI Cruises:

Click on any map to see a larger image

Also see map of Anchovy Eggs or Jack Mackerel Eggs from last April CalCOFI cruises

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