Prey Field of Larval Herring Clupea harengus on a Continental Shelf Spawning Area

Abstract

The predator-prey relationships of larval Clupea harengus L. were investigated on a continental shelf spawning area, Georges Bank-Nantucket Shoals, off the northeastern coast of the United States during 3 autumn-winter spawning seasons. Our observations are based on examination of the alimentary tracts (guts) of over 8,000 larval herring. Feeding was concentrated into 2 peaks during the daylight hours, and larvae averaged 1 to 7 prey (0.5 to 48 ~g dry weight) per gut. Larvae preyed on the synchronously developing juvenile and adult stages of the dominant copepods of this area (Pseudocalanus sp.. Paracalanus parvus, Centropages typicus, C. hamatus, Oithona spp.. and Calanus finmarchicus). During 1974, Centropages spp. and Pseudocalanus sp. dominated the larval diet; during 1975 and 1976, Pseudocalanus sp. and Paracalanus parvus were dominant. This shift in diet reflects a shift in zooplankton species distribution in the area. Larger, more robust larvae were collected in 1976 than in 1974 and 1975; survival was greater during this season, and a higher percentage of feeding larvae was observed.