Size-selective harvesting drives genomic shifts in a harvested population.

Overfishing not only drastically reduces the number of fish in an exploited population but is also often selective for body size by removing the largest individuals from a population. Here, we study experimentally the evolutionary effects of size-selective harvesting using whole-genome sequencing on a model organism, the zebrafish (Danio rerio). We demonstrate genomic shifts in the populations exposed to size-selective harvesting for five generations and show reduced genetic diversity in all harvested lines, including the control line (non-size-selected). We also determine differences in groups of genes related to certain gene ontology annotations between size-selectively harvested lines, with enrichment in nervous system related genes in the large-selected lines. Our results illuminate the biological processes underlying fisheries-induced genetic changes and hence contribute toward the understanding of the changes potentially associated with the vulnerability of an exploited population to future stressors.