Chapter 6. Predation on Post-Smolt Atlantic Salmon by Gannets: Research Implications and Opportunities
- Derek Mills MSc, PhD, FIFM, FLS
Published Online: 20 NOV 2007
Copyright © 2003 by Blackwell Science Ltd.
Salmon at the Edge
How to Cite
Montevecchi, W.A. and Cairns, D.K. (2007) Predation on Post-Smolt Atlantic Salmon by Gannets: Research Implications and Opportunities, in Salmon at the Edge (ed D. Mills), Blackwell Science Ltd., Oxford, UK. doi: 10.1002/9780470995495.ch6
Atlantic Salmon Trust
- Published Online: 20 NOV 2007
- Published Print: 7 JUL 2003
Print ISBN: 9780632064571
Online ISBN: 9780470995495
- postsmolt atlantic salmon;
This chapter contains sections titled:
Population declines of Atlantic salmon have been linked to juvenile mortality at sea. It has, however, proven difficult to document predation on marine-phase salmon. In the northwest Atlantic, gannets exhibited very low levels of predation on postsmolts during the late 1970s and 1980s. Following a regime shift in the pelagic food web in the northwest Atlantic during the 1990s, gannets markedly increased postsmolt consumption. This predation has the potential to negatively influence North American populations of Atlantic salmon. Migrating salmon pass through foraging ranges around gannet colonies, providing research opportunities for broad-scale quantification of avian predation on marine phase Atlantic salmon. Aspects of seabird research can also provide important information on the behaviour and ecology of postsmolts in the marine environment. Many conservation concerns are attributed to avian predators, such as cormorants, rather than to the circumstances that create these symptomatic interactions, e.g. temporarily restricted, mass releases of hatchery-reared fishes. Predatory influences that do exist likely contribute to cumulative effects with other sources of mortality, such as aquacultural practices, hydro-electric and other land-use activities that change flow regimes and river inputs, climate change and pesticide use.