Natural Selections: “Couch potato” bass evolving in response to human predation

North Country Public Radio

The pressure to keep billions of humans fed can have a transformative impact on amimal populations. Overharvesting that targets the largest animals can result in reduction of the average size of species, as seen in Caribbean conch snails. And sport-fishing pressure on large mouth bass can winnow out the most agressive in the gene pool, resulting in a “lazier,” more passive remnant population.

Martha Foley and Curt Stager talk about the human factor in animal evolution.

Martha Foley: We have now competitive fishing, fishing tournaments, a lot of heavy pressure on fisheries on top of people who just like to fish. Is all that fishing changing the nature of the fish or the fishery? Is it too much?

Curt Stager: Well, when we do that we are acting as predators in the ecosystem, and predators have always been in ecosystems and they certainly change the nature of their prey, and vice-versa. It’s sort of an arms race, a co-evolution thing as the predators get more effective at hunting the prey get better at avoiding being eaten, and back and forth. The same thing can happen with fish, too. It’s all a matter of degree and what the situation is, but fisheries managers have to think of this evolutionary process of natural selection, only done by people, to watch for these effects which actually do become visible sometimes in some circumstances.

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