The food of immature sprat (Sprattus sprattus (L.)) and herring (Clupea harengus L.) in coastal waters of the North Sea

Immature sprat ( Sprattus sprattus (L.)) and herring ( Clupea harengus L.) from the North Sea, caught from June 1981 to April 1982 in the cooling waters of Sizewell nuclear power station, had similar diets of copepods in fish up to 7 cm in length. Larger sprats continued to feed on copepods, but herring took increasingly larger food items as they grew. Mysids and post-larval sprat contributed most to the diet of herring 7–20 cm in length, and feeding continued throughout the year. No food organisms were found in sprats above 9 cm in length from July to February, and all sprats ceased to feed in December and January. Feeding was resumed in February and reached a peak of intensity in June. Immature sprat and herring caught at a series of stations along the length of the east coast of England in July 1984 had diets similar to those of the Sizewell fish.