Predation on northern shrimp (Pandalus borealis) by three gadoid species

ABSTRACT

Northern shrimp (Pandalus borealis) is targeted by commercial fisheries, but is also an important prey in the marine food web. In this study, stomach content data were used to study predation on shrimp by three gadoid species, cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus), in six inshore areas around Iceland. The results showed that shrimp was more important in the diet of cod compared with the other two predators. However, the overall predation pressure was similar for cod and haddock due to the high abundance of haddock. Therefore, even though shrimp is not the primary source of food for haddock, this species can have a substantial effect on shrimp stocks when haddock abundance is high. In addition, while cod and haddock did not select for any particular size of shrimp, whiting seemed to preferentially target juvenile shrimp. The results suggest that due to the overall effects of these three predators on shrimp stocks, gadoids need to be included in the management of shrimp stocks as predation is one of the major drivers in the development of this important prey stock.

RESPONSIBLE EDITOR:

• Haakon Hop

KEYWORDS:

• Cod
• haddock
• northern shrimp
• predation pressure index
• whiting

Acknowledgements

I would like to thank the captains and crews of the vessels used for sampling and all the researchers working aboard for sampling and analysis of the stomach contents. Moreover, thanks to Dr Christophe Pampoulie, Dr Anne Richards, two anonymous reviewers and the subject editor for valuable comments to an earlier draft of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author.