Lobster (Homarus gammarus) catches in southwestern Norway, including the first recaptures of previously released juveniles

Abstract

Since 1990, 20-30 000 tagged lobster juveniles have been released each year at Kvitsøy, south west Norway, by the Institute of Marine Research. In 1992 the first 19, legally sized lobsters, of these releases were caught. All were males. Tag analysis showed that they originated from a batch hatched in the summer of 1988 and released in the spring of 1990. Of the 241 undersized lobsters tested in the tag detector in 1992, 95 carried a tag, and 37 more had a pair of cutter chela - as all the lobsters released in 1990 - indicating that more than 50% of the undersized lobsters in the catch were of hatchery origin. Before returned to sea all undersized lobsters were given individual external codes for later recognition. The lobster fishery at K vitsøy has been monitored since 1991. Of the 1071 lobsters registered by local fishermen at Kvitsøy in 1991, 926 were legally sized (over 220 mm TL). In 1992 the minimum legal size was increased from 220 mm to 240 mm TL. In the spring 1992, 539 lobsters were registered, 486 of which were legally sized. In 1991, nearly 35% of the legally sized lobsters were classified as cultured juveniles originating from releases in 1985-86. In the spring 1992 about 25% were classified as released lobsters, while only 19% were characterised as released lobsters in the autumn 1992. Sex distribution was approximately equal in the autumn catches, and slightly female biased in the spring.