Chapter 5. The Significance of Marine Mammal Predation on Salmon and Sea Trout

  1. Derek Mills MSc, PhD, FIFM, FLS
  1. S.J. Middlemas1,
  2. J.D. Armstrong1 and
  3. P.M. Thompson2

Published Online: 20 NOV 2007

DOI: 10.1002/9780470995495.ch5

Salmon at the Edge

Salmon at the Edge

How to Cite

Middlemas, S.J., Armstrong, J.D. and Thompson, P.M. (2003) The Significance of Marine Mammal Predation on Salmon and Sea Trout, in Salmon at the Edge (ed D. Mills), Blackwell Science Ltd., Oxford, UK. doi: 10.1002/9780470995495.ch5

Editor Information

  1. Atlantic Salmon Trust

Author Information

  1. 1

    Fisheries Research Services, Freshwater Laboratory, Faskally, Pitlochry, Perthshire, PH16 5LB, UK

  2. 2

    Lighthouse Field Station, Department of Zoology, University of Aberdeen, Cromarty, IV11 8YJ, UK

Publication History

  1. Published Online: 20 NOV 2007
  2. Published Print: 7 JUL 2003

ISBN Information

Print ISBN: 9780632064571

Online ISBN: 9780470995495



  • marine mammal;
  • predation;
  • salmon;
  • trout;
  • predator-prey interactions



This chapter contains sections titled:

  • There is evidence that stocks of Atlantic salmon (Salmo salar) are declining on both sides of the Atlantic. There is also concern over the health of sea trout (Salmo trutta) populations, particularly on the west coast of Scotland. The decline in salmon abundance appears to be related to a decrease in marine survival. This decline, together with a concurrent growth of some marine mammal populations, has led to an increased interest in the impacts of marine mammals on salmonids. We review the published information on predation by marine mammals on salmon and sea trout. There is no evidence that marine mammals are the main causal agents for the decline in salmonid abundance. However, in areas where salmonid abundance is already low, they could have substantial local effects on populations. Problems in assessing, and defining, significant predation are discussed. Although to assess the significance of marine mammal predation fully it must be put in an ecosystem context, we are some way from achieving this.