Disentangling the causes of maturation trends in exploited fish populations

摘要

Evolutionary theory predicts that selective harvesting will shift the frequency of genes for heritable traits towards those that express well-adapted phe-notypes (Law 2007, this Theme Section). Applying this logic, commercial fisheries that select on the basis of size could reasonably be expected to favor the genotype for maturation at smaller sizes (and/or younger ages), given that rapidly maturing individuals will be more likely to reproduce prior to capture. This form of fisheries-induced evolutionary response is a parsimonious explanation for the observed long-term trend towards earlier maturation that has been observed in several commercially exploited fish stocks (Rijnsdorp 1993, Trippel 1995). Unfortunately, it is not possible to test this hypothesis directly, be-rncause the genes associated with maturation have not been isolated.