Dec 12, 2019 12:23 AM
https://www.knowablemagazine.org/article...-evolution
INTRO: Every year, people haul 1 to 3 trillion fish from the ocean. There’s little doubt that this is too many — fish populations have collapsed worldwide. But there’s another thing we are doing to fish: By killing them in such large numbers, we are exerting enormous evolutionary selection pressure. The adaptive changes that result could increase the chance that fish species will survive, but may pose a problem for the people who depend on them.
By preferentially catching the kind of fish we like — usually big ones — we are inevitably creating a disadvantageous situation for such fish. They’re less likely to survive and reproduce, which reduces the presence of their genes in the next generation. We are, in effect, creating evolutionary pressure for fish to be small. In that way, policies dictating that only large fish should be caught, and small ones left alone, could be counterproductive.
Mikko Heino, an evolutionary biologist at the University of Bergen in Norway, has spent more than 20 years trying to document and understand how humans are changing the way that fish evolve. Because it’s very hard to directly demonstrate genetic changes due to fishing, he has used a diversity of other approaches, from lab experiments to historical data analysis to computer modeling of long-term evolution.
As Heino and two coauthors explain in the Annual Review of Ecology, Evolution, and Systematics, there probably is no way for us to catch fish without evolutionary side effects. Yet he believes that taking evolution into account might put an end to well-intended but ill-advised policies and help develop more sustainable ways to manage fisheries. This interview has been edited for length and clarity... (MORE - interview)
INTRO: Every year, people haul 1 to 3 trillion fish from the ocean. There’s little doubt that this is too many — fish populations have collapsed worldwide. But there’s another thing we are doing to fish: By killing them in such large numbers, we are exerting enormous evolutionary selection pressure. The adaptive changes that result could increase the chance that fish species will survive, but may pose a problem for the people who depend on them.
By preferentially catching the kind of fish we like — usually big ones — we are inevitably creating a disadvantageous situation for such fish. They’re less likely to survive and reproduce, which reduces the presence of their genes in the next generation. We are, in effect, creating evolutionary pressure for fish to be small. In that way, policies dictating that only large fish should be caught, and small ones left alone, could be counterproductive.
Mikko Heino, an evolutionary biologist at the University of Bergen in Norway, has spent more than 20 years trying to document and understand how humans are changing the way that fish evolve. Because it’s very hard to directly demonstrate genetic changes due to fishing, he has used a diversity of other approaches, from lab experiments to historical data analysis to computer modeling of long-term evolution.
As Heino and two coauthors explain in the Annual Review of Ecology, Evolution, and Systematics, there probably is no way for us to catch fish without evolutionary side effects. Yet he believes that taking evolution into account might put an end to well-intended but ill-advised policies and help develop more sustainable ways to manage fisheries. This interview has been edited for length and clarity... (MORE - interview)