THE ROLE OF ESCAPE REACTIONS IN DETERMINING THE SIZE DISTRIBUTION OF PREY CAPTURED BY HERRING LARVAE

Fish larvae are selective planktivores, and size is an important facto r in prey selection. However, for herring larvae, a selection model ba sed solely on the principle of optimising calorific gain per unit ener gy expenditure consistently overestimates the mean size of ingested pr ey. Most such models ignore the escape capabilities and shape of the p rey, and the potential role of escape on capture success. In this pape r, a static foraging model incorporating both selection and escape is described and tested against published data on the composition of herr ing larvae stomach contents. The results indicate that prey escape is a major factor structuring the diet composition of the larvae.