Fisheries-induced rates of contemporary evolution: comparing haldanes and darwins

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Trait evolution over time periods spanning generations, not millennium, is increasingly observed to be above the natural baseline in populations experiencing human-induced perturbations. We investigated the relative speed of trait change by comparing rates of evolution in haldanes and darwins for length (or weight) at maturation from probabilistic maturation reaction norm midpoints for fish stocks from the Northwest Atlantic, Northeast Arctic and Barents Sea, and the North Sea. For stocks that had a moratorium enacting during the time period, rates were estimated for pre- and post-moratorium. Absolute rates in haldanes for 17 stocks ranged from 0.02–1.9 and from 0.5–153 in kdarwins (103 darwins) for 21 stocks. The North Sea and northwest Atlantic (pre-moratorium) cod stocks had some of the fastest rates of change (in haldanes), while post-moratorium northwest Atlantic and Icelandic cod stocks had the slowest rates. North sea sole and plaice haldane rates also tended to be slower than the average rate. When comparing rates in darwins, all stocks in the North Sea and Grand Banks, and cod stocks in the Gulf of Maine and 2J3KLNOPs (pre-moratorium time series) experienced some of the fastest evolutionary rates of change. Stating whether fisheriesinduced evolution is fast or slow has limited ecological meaning, and the focus should now be towards determining whether the rate of fisheries-induced evolution is fast enough to permanently alter ecosystem dynamics. The next stage should be to investigate the effect of these relatively fast rates of phenotypic change in terms of fisheries yields and sustainability