On distribution, size and maturity of shortfin squids (Cephalopoda, Ommastrephidae) in the North Sea

Abstract

Cephalopods are important predators and key organisms in numerous marine ecosystems, but their abundance in the North Sea, one of the most productive shelf seas, seems to be low. Here we report on three Ommastrephidae (Illex coindetii, Todarodes sagittatus, and Todaropsis eblanae) that have been caught on several North Sea cruises between 2007 and 2010. T. eblanae was most abundant (n = 269 specimens), followed by I. coindetii (n = 95) and T. sagittatus (n = 51). We provide new information on their distribution patterns for summer and winter and relate the species abundances to sampling depth, temperature and salinity. Further information is given on the species size, distributions, maturation and possible spawning sites and times in the North Sea. Although occurring in relatively low numbers, our study suggests that Ommastrephidae are distributed throughout most parts of the northern and central North Sea, underpinning their constancy and potential influence on the ecosystem.

Key words:

• Distribution and abundance
• Illex
• North Sea
• Ommastrephidae
• shortfin squid
• Todarodes
• Todaropsis

Acknowledgements

Thanks to the IBTS cruise leaders Remment ter Hofstede on RV Tridens and Brian Harley on RV CEFAS Endeavour for their support. Chingis M. Nigmatullin and two anonymous reviewers provided constructive criticism and helpful comments.

Funding

This research was funded by the German Environmental Foundation (Deutsche Bundesstiftung Umwelt, DBU).

Editorial responsibility: Geir Ottersen

Additional information

Funding

Funding: This research was funded by the German Environmental Foundation (Deutsche Bundesstiftung Umwelt, DBU).