Trophic interactions of squid in Scottish waters

• Main Authors: Pierce, Graham J., Santos, M.
• Format: Book Part
• Language: English
• Published: 1994
• Subjects: Harbour porpoise; Phoca vitulina; Phocoena phocoena
• Online Access: https://oceanrep.geomar.de/id/eprint/38009/; https://oceanrep.geomar.de/id/eprint/38009/1/2748.pdf

The main squid species of commercial importance in the northern NE Atlantic is the veined squid Loligo forbesi. The present paper reviews trophic interactions involving this species in Scottish waters. Loligo forbesi is primarily piscivorous, although the diet also includes crustaceans and there is some cannibalism. In 1990/91, the Scottish population may have eaten 9000-16 000 tonnes of food, including 1700-3000 tonnes of sandeels (Ammodytidae), a similar amount of Trisopterus spp. and 1000-1700 tonnes of whiting Merlangius merlangus. Loligo forbesi is eaten by various predatory fish, seabirds and marine mammals. Harbour seals Phoca vitulina and grey seals Halichoerus grypus eat Loligo in small amounts. Loligo forbesi is more important in the diets of harbour porpoise Phocoena phocoena. These three mammal species alone may remove more squid from Scottish waters every year than the commercial fishery. The importance of Loligo forbesi in fish and seabird diets is not well documented, although many studies indicate that other squid species are eaten.