Eastern Baltic cod grow much smaller than they did due to overfishing

Posted by littlexsparkee 7/5/2025

Eastern Baltic cod grow much smaller than they did due to overfishing(www.smithsonianmag.com)

273 points | 89 commentspage 2

thaumasiotes 7/5/2025|

The traditional approach to this problem is to harvest males and let females go. You're not going to select them out of sexual reproduction.

You will see males evolve to resemble females more closely, though.

netsharc 7/5/2025|

The fish trap will have to be quite elaborate... maybe hang Playcod centerfolds in them?

sharpshadow 7/6/2025||

Reminds me of the tuskless elephants.

https://www.nationalgeographic.com/animals/article/wildlife-...

ivanbalepin 7/5/2025||

What's impressive is that somebody, somewhere keeps collecting a nice stash of Eastern Baltic cod otoliths in hopes that somebody else would come along and invent a new way to use them.

shellfishgene 7/6/2025|

These types of time series are super important, but hard to finance as they often only yield cool papers after decades.

macinjosh 7/5/2025||

Are there any 'old fashioned' cod in captivity or maybe stored DNA samples? Maybe Collosal could splice the missing genes back in and bring them back into the gene pool.

shellfishgene 7/6/2025||

This is about Eastern Balic cod, so theoretically genes from, for example, Norwegian cod could be spliced in. However body size is usually a polygenic trait with potentially hundreds of genes involved, so that's not possible.

SoftTalker 7/5/2025|||

If there is a survival advantage to larger cod (presumably there is, or they would not have developed) and if fishing is tightly regulated, they should return eventually.

gcanyon 7/5/2025||

Not necessarily — the “large” genes could literally have been extracted from the gene pool.

It’s possible for them to mutate back into existence, but that’sa lower-probability, much longer proposition than if the genes are still available and just selected against.

gcanyon 7/7/2025||

* I meant "extincted" from the gene pool -- auto-correct un-corrected me...

eMPee584 7/5/2025||

Or, instead of wooly mammoths, bring back fishy ones.

weregiraffe 7/6/2025||

If you catch by weight, does it matter how big the fish is? A ton of cod is a ton of cod.

lblume 7/6/2025|

It is easier to design nets that only catch big cods and don't also catch too much garbage.

PicassoCTs 7/6/2025||

We need to make certain parts of the world- unfishable- as in drag-net destroying pylons on the sea-floor, the waters mined with drones that attack any boat entering with the intent to fish. Its the only thing working against the international lawlessness picking the planet clean.

blueflow 7/6/2025|

How are the drones going to recognize intent?

cratermoon 7/5/2025||

Spoiler: because overfishing altered their genes

LarsDu88 7/6/2025||

The overfishing altered the allele frequencies of certain genes.

Actually directly altering the genes would have to involve mutation or direct engineering which is a bit more involved.

I think a good way to think about this is with human dwarfism. Many humans with achondroplasia get it through de novo mutation, but some get it by a combination of having two recessive loss of function genes that get transmitted by both parents (often of normal height)

Now imagine a laser beam that went and killed every human above a certain height. Young people would be spared along with adults with dwarfism. Over many generations, previously rare genes for dwarfism would increase in frequency shifting the average height of the population lower and lower.

It is the change in frequency that matters here more than the underlying explanation of what changed the genes.

delfinom 7/5/2025||

Overfishing didn't alter their genes. It altered the genepool.

3eb7988a1663 7/5/2025|||

To be fair, that is the subtitle, "Eastern Baltic cod grow to much smaller sizes than they did just 30 years ago, because overfishing altered their genes, according to new research"

delfinom 7/6/2025||

Yea, modern day journalists have really poor education and brainrot :/

arusahni 7/6/2025||

Thanks for this cod piece.

mscavnicky 7/5/2025||

Regression?

aaron695 7/6/2025|

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