Juvenile herring prey on Barents Sea capelin larvae

Due to a negative correlation between juvenile herring abundance and Barents Sea capelin recruitment, it has been hypothesised that predation by herring (Clupea harengus, L.) causes poor recruitment in the capelin stock (Mallotus villosus, Müller). In order to investigate whether herring are important predators of larval capelin, stomachs of herring were collected in the Barents Sea during the summers of 1992 and 1993. Capelin larvae were found in 5.6 and 3.0 % of the herring stomachs collected in the two years respectively. Herring showed preference for the larger capelin larvae. The observed predation rates correspond to estimated encounter rates between individual herring and larval capelin. The study confirms that predation takes place, but the observed rates are too low to explain the poor capelin recruitment in the two years. Increased swimming speed and selective feeding by herring in areas with high densities of capelin larvae is proposed as a mechanism that can explain the recruitment failure of the capelin stock.