Expected rate of fisheries-induced evolution is slow
Friday Seminar by Ken Haste Andersen
Commercial fisheries exert high mortalities on the stocks they exploit and the consequent selection pressure leads to fisheries-induced evolution of growth rate, age and size at maturation, and reproductive output. Productivity and yields may decline as a result, but little is known about the rate at which such changes are likely to occur. Fisheries-induced evolution of exploited populations has recently become a subject of concern for policy makers, fisheries managers and the general public, with prominent calls for mitigating management action. I demonstrate how to make a general evolutionary impact assessment of fisheries by calculating the expected rate of fisheries-induced evolution and the consequent changes in yield. Rates of evolution are expected to be about 0.1--0.6 % per year and the consequent reductions in fisheries yield are less than 0.7 % per year. These rates are at least factor of 5 lower than published values based on experiments and analyses of population time series and we explain why the published rates may be overestimates.
Ken Haste Andersen
Associate professor in fisheries science
Technical University of Denmark