9 ms·
Eastern Baltic cod grow much smaller than they did due to overfishing
- littlexsparkee 1y agoHad to truncate the title to fit 80 char limit Pertains to Eastern Baltic cod, not all
- cratermoon 1y agoSpoiler: because overfishing altered their genes
- delfinom 1y agoOverfishing didn't alter their genes. It altered the genepool.
- 3eb7988a1663 1y agoTo 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 1y agoYea, modern day journalists have really poor education and brainrot :/
- deleted 1y ago[deleted]
- LarsDu88 1y agoThe 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.
- mscavnicky 1y agoRegression?
- macinjosh 1y agoAre 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.
- SoftTalker 1y agoIf 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 1y agoNot 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 1y ago* I meant "extincted" from the gene pool -- auto-correct un-corrected me...
- eMPee584 1y agoOr, instead of wooly mammoths, bring back fishy ones.
- shellfishgene 1y agoThis 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.
- ryao 1y agoMy take away from this is that letting the small fish go under the premise that they are juveniles that will later grow to be bigger lets the adult midgets go, ruining the gene pool. I wonder if this finding will have any impact on conservation rules against taking small fish when fishing.
- thaumasiotes 1y ago> ruining the gene pool In what sense? Is being bigger Platonically better than being smaller?
- thatguy0900 1y agoIt's better if you want to eat them lol
- bluGill 1y agoSmall fish generally taste better in my experience. Small of course implies younger, so we let the biger ones go as well as small ones - there is a too small to eat point.
- deleted 1y ago[deleted]
- hungmung 1y ago> Is being bigger Platonically better than being smaller? Maybe, most animals evolve towards larger sizes. Except on smallish islands, where they tend to become smaller.
- deleted 1y ago[deleted]
- thaumasiotes 1y ago> Maybe, most animals evolve towards larger sizes. This is not even a little bit true.
- thaumasiotes 1y agoThe 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 1y agoThe fish trap will have to be quite elaborate... maybe hang Playcod centerfolds in them?
- gouthamve 1y agoRelated, this is an excellent book on Cod fishing and how it helped humans and finally how overfishing has hurt the Cod numbers: https://www.markkurlansky.com/books/cod-a-biography-of-the-fish-that-changed-the-world/ https://www.markkurlansky.com/books/cod-a-biography-of-the-f... It might sound like a boring topic, but it's one of the best books I've read and something I recommend a lot.
- jbaber 1y agoBy the author of Salt and interesting in the same way for the same reason. Much shorter!
- ivanbalepin 1y agoWhat'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 1y agoThese types of time series are super important, but hard to finance as they often only yield cool papers after decades.
- jongjong 1y agoI've often made the argument that evolution can happen very quickly within a few generations and doesn't necessarily take millions of years. It's interesting to see some cases in nature where rapid changes in a predator's behavior (in this case humans) can radically alter a visible trait.
- maxbond 1y agoI knew someone who started a farm of Spirulina (a microscopic, edible algae [cyanobacteria]) in a very different climate from where the seed culture originated. They did really poorly for the first few days, they were the wrong color and the culture wasn't growing. But eventually they adapted to the new climate and bounced back, and he was able to scale the culture up to multiple greenhouses and harvest it on an ongoing basis.
- im3w1l 1y agoBefore concluding a genetic change took place I would want to rule out alternative hypotheses. Maybe the cyanobacteria needed to do a mode switch which took time, maybe some parasite had to die, or some symbiote had to enter the culture. Yeah I'm just kinda throwing things out there, but still.
- morkalork 1y agoThe one that gets me is the Soviet experiment in domesticating foxes that worked after a few dozen generations. How many generations have humans been around with tools and technology? We've been domesticating ourselves.
- cortesoft 1y agoIs this really an argument or just fact? From what I understand, the modern accepted view of evolution is that it happens in a sudden step wise manner... there will be an equilibrium, where the ecosystem is fairly stable and species don't change much, and then some shock or change will happen and evolution will be rapid, over a relatively short period. This makes sense if you think deeply about it; evolution will only happen when the 'normal' genetic expression stops surviving, otherwise the random variations will even out.
- thriorruii5785 1y agoModernity/Capitalism supercharges the hate Christianity has for nature, and well take out the earth with ourselves in the process soon. Hail the great anthropocene.
- rr808 1y agoI'm sure I read somewhere that Maori fishermen used to eat small-mid sized fish and left the largest ones because they were the best breeders. I can't find a reference now but has logic.
- robocat 1y agoThat is for eels. I met a fella whose income came from going up coastal streams (canoe? Dingy with outboard?) to catch eels to sell. He definitely left the largest (queens?). Good article: https://ourwayoflife.co.nz/from-vermin-to-icon-new-zealands-long-and-fascinating-relationship-with-eels/ https://ourwayoflife.co.nz/from-vermin-to-icon-new-zealands-... Also interesting: https://www.1news.co.nz/2025/04/05/thousands-of-eels-found-dead-near-canterbury-lake/ https://www.1news.co.nz/2025/04/05/thousands-of-eels-found-d...
- goosedragons 1y agoIn most fish, larger size = more eggs or more sperm. So yes, largest ones are typically the best breeders. IIRC some species like I think some tuna they don't harvest the largest on purpose.
- lambdasquirrel 1y agoReminds me of a line that Philip Glass co-opted for his 5th Symphony: “Therefore the land mourns, and all who dwell in it languish, and also the beasts of the field and the birds of the heavens, and even the fish of the sea are taken away.”
- aziaziazi 1y agoMeat: To Eat It or Not - Philip Glass https://tricycle.org/magazine/meat-eat-it-or-not-philip-glass/ https://tricycle.org/magazine/meat-eat-it-or-not-philip-glas... https://web.archive.org/web/20250321203216/https://tricycle.org/magazine/meat-eat-it-or-not-philip-glass/ https://web.archive.org/web/20250321203216/https://tricycle.... A very poetic and spiritual take, however IMHO he missed the elephant in the room for the compassion argument: breeding is much more cruel than killing by the harsh, prolonged condition. The killing in comparaison is nearly instant and arrive as a relief of that condition. Both comes together though and only considering the quicker and "natural" one isn’t fair.
- skeledrew 1y agoI don't like how this is worded. Makes it sound as though the cod are actively reducing their size. But this is very straight forward Darwin's Theory, survival of the fittest, in action. In this case, the "fittest" cod are the ones with the propensity to be small, since they can escape the nets and survive to breed and pass on that propensity. And it follows that there won't be a "bounce back" of the larger cod any time soon, as it takes thousands of years in a minimally interrupted state for such diversity to come about in nature. Of course this applies to all other living creatures as well.
- VWWHFSfQ 1y ago> it takes thousands of years in a minimally interrupted state for such diversity to come about in nature The article says it only took 30 years to kill off all the big cod by only allowing the generically-smaller cod to escape and continue breeding. Now that all the eastern cod are protected, maybe it will only take 30 years for the gene pool to return to normal size distribution.
- griffzhowl 1y agoI'm pretty sure it doesn't work like that: previously there were genetic variants for large and small sizes. Now a high proportion of the larger variants have been removed from the gene pool. To reverse that in a similar time frame would need a massive selection pressure on the smaller variants. So you would need something like industrial scale fishing that removed the smaller adults, but didn't take out the juveniles who would become big fish, while also letting go the bigger adults. It doesn't sound feasible
- arusahni 1y agoThanks for this cod piece.
- aaron695 1y ago[dead]
- PicassoCTs 1y agoWe 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 1y agoHow are the drones going to recognize intent?
- yard2010 1y agoThis is why I'm afraid of mosquitoes. Fighting them means creating a superhuman (super mosquito?) version that will be resistant to everything. When they find new diseases to obliterate the human race with, we are done. Personally, I believe that mosquitos are far more concerning than any other impending environmental disaster.
- lblume 1y agoTechnology and memes spread faster than genes. Mosquitoes adapting that fast is not an issue that serious. Additionally, if hundreds of thousands of Americans died of malaria each year, we would have found much more effective cures (consider that there are already very effective ones that simply aren't widely used), just like we did with Covid.
- madaxe_again 1y agoThe U.S. would quite simply not exist if it were a malaria zone. Endemic diseases shape societies, profoundly.
- olelele 1y agoThe other thing about the Baltic Sea is that there has been so much fertiliser and toxic farming chemicals running into it since the start of the agricultural revolution that the fish is full of heavy metals and toxins. The Swedish authorities recommend against eating it more than once a month and never for pregnant women and people with health conditions. This farming runoff overload has also led to huge areas where the sea floor is completely dead.
- Hilift 1y agoCrabs in the Chesapeake Bay are the same. About 80% of tidal segments there are contaminated with PCB's and heavy metals. Regulators describe them as "impairments", and recommend not eating them more than once per month. Cod are bottom feeders and are affected by pollution that settles to the bottom.
- gyudin 1y agoClassic and, as usual, nobody is held accountable for it. Classic EU.
- olelele 1y agoFrom what I recall this runoff was the most intense between 1950-1980.
- weregiraffe 1y agoIf you catch by weight, does it matter how big the fish is? A ton of cod is a ton of cod.
- lblume 1y agoIt is easier to design nets that only catch big cods and don't also catch too much garbage.
- sharpshadow 1y agoReminds me of the tuskless elephants. https://www.nationalgeographic.com/animals/article/wildlife-watch-news-tuskless-elephants-behavior-change https://www.nationalgeographic.com/animals/article/wildlife-...
- veidelis 1y agoWhat I've had heard so far about cod's troubles in the Baltic sea is that it's not salty enough for them. For cod to reproduce, their eggs need a certain salinity so that they swim to the right depth after they are spawned. Here's an article in Latvian news site about it - https://nra.lv/neatkariga/intervijas/481931-mencu-zveja-baltija-beigusies-un-ne-jau-eiropas-lieguma-del.htm https://nra.lv/neatkariga/intervijas/481931-mencu-zveja-balt...