Seasonal Catches, Size and Meristic Data for Sprat, Sprattus Sprattus, in the Severn Estuary

Abstract

Samples collected at regular intervals from the intake screens of power stations have been used to provide data on various aspects of the biology of sprat in the Severn Estuary between November 1973 and June 1977. Young sprat took approximately 4 months to pass from spawning regions outside the central Bristol Channel to inshore areas in the inner Severn Estuary. The influx into this latter region of these new o+ recruits (minimum standard length 26 mm) produced a pronounced peak in catches in either August or September, while a secondary peak between January and March was due to the immigration of larger and older fish (80-143 mm). o+ sprat did not increase markedly in size between the autumn and following spring, with the result that the modal standard length was still only ca. 50 mm at the end of the first year of life. The copepod parasites, Lernaeenicus sprattae (Sowerby) and Lernaeenicus encrasicola (Turton), were found on the eyes of 3.2% of sprat and on the dorsal surface of 0.3% of sprat respectively. Meristic characters for the Severn Estuary population are compared with those recorded for sprat in other parts of Europe.