The rate of evolution due to natural selection is generally so slow that the consequences only become apparent over tens of thousands of years. However if the selection pressure is strong and acts on a trait that has high heritability then changes may occur much more rapidly, as shown by the success of selective breeding programmes in agriculture.
Over the past few years concern has been increasing over the selective effects of commercial fishing and evidence of fisheries-induced evolution of growth rate, maturation, and reproductive output has accumulated. Such changes may result in lower productivity and yields and have therefore become a subject of concern for policy makers, fisheries managers and the general public.
The urgency of taking appropriate management action depends on the rate at which evolution is happening and a study published online this week in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) by research scientists Ken H. Andersen and senior research scientist Keith Brander, National Institute of Aquatic Resources, Technical University of Denmark, makes an estimate of this rate.
Calculated rates are lower
The expected rate of evolution and impact on fisheries yields are calculated using generalized quantitative genetics. The rates of evolution from this theoretical calculation are at least a factor 5 lower than previous estimates based on experiments and analyses of observed population time series.
This discrepancy between the predictions of life history theory and empirical measurements may be a sign of inadequacies in life history theory, but may also be to be due to errors arising from indirect statistical inferences of genetic change, or deficiencies in the underlying data and assumptions in the empirical estimates.
If the rate of fisheries-induced evolution is indeed slower than had previously been estimated then the need for management action is less urgent. However even slow evolution may be undesirable and the next stage in the work will be to design measures that can neutralize or reverse such effects.
For further information please contact:
Research Scientist Ken Haste Andersen
National Institute of Aquatic Resources, Technical University of Denmark
kha@aqua.dtu.dk
+ 45 33 96 34 00