Predation on the eggs of Norwegian spring-spawning herring at a spawning ground outside the westcoast of Norway in 1981

Predation on the eggs of demersal spawners has been reported several\ntimes, and findings of haddock feeding on capelin or herring eggs is a\nwell known phenomenon. A spawning ground where spawning has been\ndetected through several years was selected as the study-area and\ninvestigations on the predation were carried out in three steps; a)\nstomach sampling, b) controlled experiments to find the rate of\ngastric emptying of herring eggs and c) bioacoustic surveys to study\nthe distribution and abundance of predators. Haddock was found to be\nthe main predator on eggs in the area. The total amount of fertilized\nherring eggs being eaten in a period of 30 days was estimated to be\nabout 10 000 metric tonnes. This is the spawning product of about\n20 000 tonnes of herring.