The influence of stock structure on fisheries-induced evolution in Icelandic cod

Marine Research Institute, Reykjavik, Iceland

Heidi Pardoe

Heidi Pardoe

Changes in life-history traits, particularly in age and size at maturation, have been reported in a number of commercially exploited fish stocks. Many studies have found fisheries-induced evolution to be a plausible explanation for the observed trends. Evidence for the existence of adaptive variation and local populations within several cod stocks has been found. One such stock is Icelandic cod for which spawning, life-history characteristics, condition and abundance vary spatially, and there is also evidence of genetic structure. Furthermore, fishing mortality of the Icelandic cod stock is unevenly distributed on the Icelandic shelf. Preliminary investigations suggest that age and size at maturation in this stock has declined over the last few decades. In line with the majority of fish stocks, Icelandic cod is currently managed as a single homogenous unit. However, failure to recognise or account for stock diversity could produce misleading results or even potentially severe ecological consequences. In this project, my aim is to investigate the development and subsequent dynamics of structure in a stock such as Icelandic cod and its influence on the rate, detection, and management of fisheries-induced evolution, with additional consideration of the role of variable fishing pressure on individual stock components. The development of an individual-based eco-genetic model will help tackle these research questions where empirical analysis would fail due to the limitations imposed by data availability.

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Last edited: 30 June 2016

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