Swimming speed of spent Norwegian spring spawning herring

Abstract

In March 1990 spent Norwegian spring spawning herring were tagged on the spawning grounds off Karmøy in southwestern Norway. 37 of these tagged herring were recaptured approximately 40 hours later. The recapture took place west of Bergen, some 60 nautical miles north of the tagging position. The herring seemed to move in schools in the upper water masses, and were appearently carrying out a migration to the feeding grounds in the Norwegian Sea. The herring moved in a northward flowing coastal current (salinity less than 35 % ) with temperatures of 5-6°C. A minimum swimming speed (sustained for at least 40 hours) can be estimated to 1.4 knots. With reference to the length (BL) of the herring the speed is 2.2BL x sec^-1. Although obtained under different environmental conditions, this result is in agreement with earlier estimates obtained from echo sounding records, of the swimming speed of migrating Norwegian spring spawning herring. Further, the present report gives details of the tagging, the recapture and of the biology of the herring.