Food availability and predator presence in a coastal nursery area of the Brown Shrimp (Crangon crangon)

Abstract

Abstract Along the marine, sandy coast of the Netherlands between Wassenaar and Egmond, large recruitment to the adult stock of Crangon crangon occurs annually in September–November. This recruitment is the result of settlement in this area of postlarval C. crangon in late May–July. This short and sharply defined period of settlement contrasts with the situation in Dutch estuarine nursery areas, where large-scale settlement occurs in April–October. The coastal zone Wassenaar-Egmond is strongly eutrophicated by river water sluiced at Hook of Holland. The settlement of C. crangon is linked with a bloom of calanoid copepods in May–July. Calanoid copepods are here the major food item for C. crangon of 10–20 mm and these pelagic organisms form a practically unlimited food supply for bottom-dwelling shrimps. Predation on juvenile C. crangon is light in May–July, because predation by 0-group fish becomes significant not earlier than August. Due to the unlimited food supply and low level of predation, recruitment...