Stable isotopes reveal age-dependent trophic level and spatial segregation during adult marine feeding in populations of salmon
|Author(s)||Mackenzie Kirsteen1, Trueman Clive N.1, Palmer Martin R.1, Moore Andy2, Ibbotson Anton T.3, Beaumont William R. C.3, Davidson Ian C.4|
|Affiliation(s)||1 : Univ Southampton, Sch Ocean & Earth Sci, Natl Oceanog Ctr Southampton, Southampton SO14 3ZH, Hants, England.
2 : Cefas, Lowestoft NR33 0HT, Suffolk, England.
3 : Game & Wildlife Conservat Trust, Wareham BH20 6BB, Dorset, England.
4 : Environm Agcy, Buckley CH7 3AJ, Flint, Wales.
|Source||Ices Journal Of Marine Science (1054-3139) (Oxford Univ Press), 2012-11 , Vol. 69 , N. 9 , P. 1637-1645|
|WOS© Times Cited||29|
|Keyword(s)||microchemistry, migration, North Atlantic, Salmo salar, scales|
Locating and differentiating the marine feeding areas used by adult salmon (Salmo salar) is essential to stock-based management and conservation, but traditional tagging studies are limited and influenced by the uneven distribution of the fisheries or research vessel surveys. Here, a novel approach is used, based on the observation that the isotopic composition of animal tissues is intrinsically linked to the environmental conditions during tissue growth, which allows for the distinction of pelagic fish feeding in different locations. This isotopic approach is applied using archived collections of salmon scales and shows that (i) salmon act as size-structured pelagic predators, (ii) adult salmon from different natal origins within the UK (and hence components of the southern European stock complex) feed in different oceanic regions before their return, (iii) one-sea-winter (1SW) and multi-sea-winter salmon returning to some rivers in the UK are separated in their marine feeding areas, whereas those from others are not, and (iv) salmon from the rivers sampled are not feeding in regions of the Northwest Atlantic used by 1SW salmon returning to rivers in Newfoundland. Therefore, the stable isotope approach allows for retrospective investigations of marine diet, location, and migration at stock-and cohort-specific levels.