Identifying potential for fisheries-induced evolution on behavioral traits of a Skagerrak cod (Gadus morhua) population.

Abstract

Fisheries activities and the development of more efficient fishing gear, have had detrimental effects in commercial stocks. This occurs largely as a result of negative selection acting on certain individuals during the harvesting process. Empirical observations show that fishing mortality and/or selective fishing pressure, leads to reductions in age and size at maturity of fish. Research shows that this is not only driven by phenotypic plasticity, but also by an evolutionary mechanism. Similarly, behavior is a trait subject to harvest selection and is subject to genetic changes at the population level. This is expected to have negative consequences derived from depletion of genotypes specialized to a particular food and habitat use. A loss of such adaptive capacity could potentially cause diminished resilience of the stock. The impact of fisheries on behavior has gained attention in the last decades but few approaches have studied wild commercial fish. The objective of the present work was to characterize the relationship between two behavioral variables related with fisheries and reproductive success to detect potential for harvest selection in behavior of Skagerrak cod. Contrary to what was expected, no relationship between the variables and reproductive success was found suggesting either, lack of potential or, poor sampling. Further experiments should consider the role of the area where the experimental fish come from and the capture methods used.