Publication Abstract

Fish location at sea revealed by carbon isotopes

K. M. MacKenzie, C. N. Trueman, M. R. Palmer, A. Moore* and D. J.S. Poulter

An understanding of the distribution and structure of marine fish populations is a fundamental goal of marine ecology, as well being essential to the conservation and management of fish stocks.  Despite its importance, this problem has proven difficult to study directly. In a novel approach, we show that the location of fish populations can be identified by comparing temporal variations in tissue carbon isotopes and sea surface temperatures. Application of this technique to Atlantic salmon (Salmo salar, L.) shows that separate river stocks and cohorts form geographically distinct populations that feed outside of historic fishery areas. Our analysis has immediate implications for management and conservation of wild Atlantic salmon stocks, and is applicable to any marine fish population for which tissue archives are available.