Continuous variation in the pattern of marine v. freshwater foraging in brown trout Salmo trutta L. from Loch Lomond, Scotland

Etheridge, E.C., Harrod, C., Bean, C. and Adams, C.E. (2008) Continuous variation in the pattern of marine v. freshwater foraging in brown trout Salmo trutta L. from Loch Lomond, Scotland. Journal of Fish Biology, 73(1), pp. 44-53. (doi: 10.1111/j.1095-8649.2008.01905.x)

Abstract

Carbon stable-isotope analysis showed that individual brown trout <i>Salmo trutta</i> in Loch Lomond adopted strategies intermediate to that of freshwater residency or anadromy, suggesting either repeated movement between freshwater and marine environments, or estuarine residency. Carbon stable-isotope (δ¹³C) values from Loch Lomond brown trout muscle tissue ranged from those indicative of assimilation of purely freshwater-derived carbon to those reflecting significant utilization of marine-derived carbon. A single isotope, two-source mixing model indicated that, on average, marine C made a 33% contribution to the muscle tissue C of Loch Lomond brown trout. Nitrogen stable isotope, δ¹⁵N, but not δ¹³C was correlated with fork length suggesting that larger fish were feeding at a higher trophic level but that marine feeding was not indicated by larger body size. These results are discussed with reference to migration patterns in other species.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Adams, Professor Colin
• Authors: Etheridge, E.C., Harrod, C., Bean, C., and Adams, C.E.
• Subjects: Q Science > QL Zoology
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Journal of Fish Biology
• ISSN: 0022-1112