Size and age-dependent changes of escape response to predator attack in the Queen scallop Aequipecten opercularis

Abstract

Physiological fitness and exercise capacity decrease with age in humans and rodents, a finding for which, among other causes, the decline of cellular and especially mitochondrial functions with age is held responsible. We investigated changes of escape response to predator attacks in swimming scallops (Aequipecten opercularis) with size using the natural predator Asterias rubens. Aequipecten opercularis swim mainly to avoid predators and a decrease in swimming abilities would increase risk of capture and lower survival. The queen scallop A. opercularis is a very active, epibenthic species with a short lifespan of 8–10 years and a shell height up to 90 mm in the investigated fishing ground around the Isle of Man. No difference in clap rate was found between smaller and bigger A. opercularis individuals, but differences were found in swimming mode (jumping and swimming) and valve opening and closure behaviour between the two size groups in response to predator attack. Smaller individuals showed less jumping movements and closed valves more often and remained closed for longer time than bigger animals. The difference in swimming behaviour is discussed in respect to size and age-dependent changes in morphology and cellular physiology as well as interactions of different main predators (sea stars, crabs) with the different size classes.

Keywords:

• Predators
• scallops
• size
• swimming

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

We would like to thank Dr A. Brand and co-workers for the possibility to work at the Port Erin Marine Laboratory of the University of Liverpool and Ian Skelly for fishing Aequipecten opercularis. Thanks also to Dr T. Brey (AWI) for statistical support. We would like to thank two anonymous referees for helpful revision of this paper.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark