Distribution, movement and stock structure of three ray species in the North Sea and eastern English Channel

Abstract

Tagging experiments on three ray species, thornback ray (Raja clavata), spotted ray (R. montagui) and starry ray (R. radiata), carried out between 1959 and 1976 have been analysed, and distribution and movements are described. Within the North Sea each species belonged to a single stock. For the thornback and spotted rays a separate stock could be identified in the eastern English Channel. After an initial period of dispersion the three species remained resident within an average of 30–50 nautical miles (North Sea) or 10–15 nautical miles (English Channel) of the release area. Adult thornback rays migrated from offshore, relatively deep (30 m) water in the winter months to inshore, shallow (10 m) water in the summer months, probably to mate and spawn.