Fish are shrinking around the world. The average body weight of nearly three-quarters of marine fish populations sampled dropped between 1960 and 2020, a recent study suggests.

boem@lemmy.world to World News@lemmy.world – 132 points –
washingtonpost.com
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no one can agree why

I think most people can agree it's a combination of pollution, overfishing and climate change. Probably just unclear which one of those factors in the most.

Crazy idea, but what about fishing-driven evolutionary pressure. If all the biggest fish are getting caught and killed, won't that give smaller fish an evolutionary advantage?

Very possible, but with all things happening it's pretty hard to be sure it's that and not fish growing less because they're being poisoned by microplastics.

Nailed it. Exactly the answer I read in an article way back when. Commented on it above.

Remove the big fish, only the smaller ones that came to maturity faster get to reproduce.

Given nature's survival of the fittest, you miiight be onto something.

He's not. It's the big fish that avoid getting caught.

If all the biggest fish are getting caught and killed, won’t that give smaller fish an evolutionary advantage?

Fishing is a little bit different than that. It's the big fish who are able to avoid getting caught, which is how they get to live to be so big.

Maybe if we're talking line fishing, but I'm pretty sure most commercial fishing is done with trawling nets, where everything above a certain size is caught.

Of course, spending so much time in the cold water. There will be significant shrinkage.

I want a new Titanic movie, but instead of the Orchestra playing till the end, there should be a bunch of Lemmy jokesters making witty comments in the face of unavoidable doom.

I toured the Tsukiji Fish Market in Tokyo, right before it moved to Toyosu. The guide mentioned that giant tuna being caught today, as big as they are, are smaller than they used to be.

I suspect it's probably because of stress.

Overfishing, temperature changes, medical substances, ...

Nah, read about this in the 90's (I think?). The article was about a specific Atlantic fish, I forget, been a long time. Scientists were puzzled as to why the fish were shrinking.

Fisherman are only allowed to keep the big ones, throw the little 'uns back. This creates evolutionary pressure for younger/smaller fish to come to maturity and start reproducing sooner.

This is the best summary I could come up with:


There’s something fishy going on in the water.

Across Earth’s oceans, fish are shrinking — and no one can agree why.

It’s happening with salmon near the Arctic Circle and skate in the Atlantic.

Nearly three-fourths of marine fish populations sampled worldwide have seen their average body size dwindle between 1960 and 2020, according to a recent analysis.


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