Fitness of hatchery-reared turbot, Scophthalmus maximus L., for survival in the sea: first year results on feeding, growth and distribution

Three thousand reared turbot, Scophtha/mus maximus L., juveniles with an initial wet weight of 158 g were extcrnally tagged using T-anehor tags and released in six areas of the Ría de Vigo (NW Spain). Although these fish had been eultured, the natural food of al! those reeaptured consisted basieal!y of fishes (96%), with a remarkable presence of sand eel, Ammodytes tobianus (L.) (78%), in the gut contents. Growth of the recaptured fish is similar to that reported in the area, increasing from 144g to a final mean weight of l'2kg 14 months later. The distribution of the fishes released at less than 25 m depth is local, coneentrating in the release area (within a radius of 5 nautical miles), but those released on the continental shelf at more than 50m depth (50-90m) show important migrations along the Galician eoast. The recapture percentage 1 year after their relcase is 9·5%, joining nowadays the cornrnercial fishery with a mean weight of about 1·3 kg and a reported reeapture periodieity of 2-4 individuals per wcek. The distribution , growth, feeding and survival in the sea reported in this paper makes the hatchery-reared turbot suitable for enhancement programmes in the Galieian rías.Versión del edito