Journal of the Marine Biological Association of the United Kingdom

Research Article

Predatory Relationships of Two Sympatric Squid, Todaropsis Eblanae And Illex Coindetii (Cephalopoda: Ommastrephidae) in Galician Waters

M. Raseroa1, A.F. Gonzaleza1, B.G. Castroa1 and A. Guerraa1

a1 Instituto de Investigations Marinas (CSIC), C/Eduardo Cabello 6, 36208 Vigo, Spain

The natural feeding of the two most abundant ommastrephid squid (Cephalopoda: Ommastrephidae) in Galician waters was studied and compared. A sample of 334 stomach contents of Todaropsis eblanae (34–222 mm ML) and 267 stomach contents of Illex coindetii (50–379 mm ML) caught by commercial trawlers was examined. A total of 21 (T. eblanae) and 23 (I. coindetii) different prey items, belonging to three zoological groups (Teleostei, Crustacea and Cephalopoda), were taken by these cephalopods. However, 43% of the T. eblanae diet comprised only one fish species, Micromesistius poutassou. The diet of these squid species was significantly influenced by the geographical area (both species), size (T. eblanae) and maturation (I. coindetii). Feeding rate of both species decreased with size, but the percentage of stomachs with food remains increased in maturing and mature females. Weight of prey captured was dependent on available prey sizes and, in small individuals, maximum prey weight was very close to the squid weight. Both squid species are mainly neritic nekto-benthic predators, but I. coindetii seems to have a broader and more pelagic diet.