Density?dependent natural selection mediates harvest?induced trait changes

Rapid life-history changes caused by size-selective harvesting are often interpreted as a response to direct harvest selection against large body size. However, similar trait may result from harvest-induced relaxation of natural for size via density-dependent selection. Here, we show evidence such favouring large-bodied individuals at high population densities, in replicated pond populations medaka fish. Harvesting, contrast, selected directly and, parallel, decreased densities. Five years were enough harvested and unharvested inherit the classically predicted differences, whereby grew slower matured earlier than medaka. We that this divergence was not driven smaller populations, but larger populations.