Continuous, underway sampling of eggs of Pacific sardine ( Sardinops sagax) and northern anchovy ( Engraulis mordax) in spring 1996 and 1997 off southern and central California

Abstract

Eggs of the northern anchovy and Pacific sardine were sampled at 3 m depth using the Continuous, Underway Fish Egg Sampler (CUFES) during two cruises off southern and central California in March and April 1996 and 1997. Simultaneous measurements were made of seawater temperature and salinity. Real-time AVHRR satellite images of sea surface temperature were processed onshore and transmitted to the ship at sea. Sardine and anchovy eggs were identified and counted live, at sea, and again ashore, preserved. A total of 2129 CUFES samples were collected during 41 d at sea and contained 62,409 sardine and 15,123 anchovy eggs. Sardine eggs were widespread and abundant in both cruises (mean concentrations: 5.2 and 5.1 eggs m −3) at and shoreward of the eastern boundary of the California Current. Anchovy eggs were found primarily inshore in the Southern California Bight and were less abundant (0.4 and 1.0 eggs m −3, respectively, for the two cruises). Temperature–salinity plots indicated distinct separation of the spawning habitat of these two species and consistency in habitat between cruises in successive years. The distributions of sardine eggs and euphausiids collected by CUFES were complementary in space and time.