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When a fishery crashes, it is dramatic and takes a long time to recover if ever. There's been plenty of fisheries like cod that one could not conceive being dep

When a fishery crashes, it is dramatic and takes a long time to recover if ever. There's been plenty of fisheries like cod that one could not conceive being depleted but it has been now for decades. Estimates of catches, mortality, existing stock are prone to error because we don't really know much about how fish live and their overall population. But once that crash happens it is known and too late. Cod crashed in 1992 and still hasn't recovered

rukuu001 2mo ago
Yes, seen this happen in Tasmania, Australia with crayfish, scallops and orange roughy. Each went from free-for-all to highly managed quotas within a few years. Roughy fishing stopped completely back then, don't know what the status is now. > we don't really know much about how fish live and their overall population Absolutely yes. Orange roughy is a good example - it was caught by trawlers when they were massed in huge balls near the surface. Easy to get a big catch quickly. Turns out this was when they were spawning, so breeding cycle was being interrupted, which led to catastrophic declines very quickly.
- 2b3a51 2mo ago
  My understanding is that the cod fishery decline in Atlantic waters has had limited recovery because the ecological niche that the cod fish occupied has been taken over to some extent by a small shark species. The wikipedia page mentions 'trophic cascade' so larger populations of prey species but does not mention the shark takeover. Either way cutting the harvesting won't bring the fish back.
  - Frieren 2mo ago
    > because the ecological niche that the cod fish occupied has been taken over to some extent by a small shark species. That is very interesting, I wish this kind of things were taught in school. Too many people think that animals just exists in the current state for ever. When in reality it is a dynamic system that once changed cannot be brought back.
    - Schlagbohrer 2mo ago
      Too many people think food grows on a grocery store shelf. If they've never grown a plant from seed and eaten the result, it is hard to internalize the reality of the supply chain.
    - TeMPOraL 2mo ago
      There are two sides to it. The other side is: what people consider current "balance of nature" is just a transient state. Species die off all the time, ecosystems last millenia and then suddenly collapse, then rebound and look completely different. Protecting the habitability of our planet is paramount, but overindexing on how any particular aspect of it looks at any moment is a fool's game.
      - xyzzy_plugh 2mo ago
        This is true of trees even. People think forests have looked the same for all time but trees are frequently pushing each other out of areas. Disease and pests play a huge role as well. There's some amount of introduced pressure due to invasive species of both trees and pests but it's always been this way. Everything is in flux all the time. Stable pockets exist but they're relatively rare.
      - expedition32 2mo ago
        The planet will literally survive anything. Life finds a way. There were supervolcanoes that blanketed the skies for millions of years. But human civilization as we know it is fragile.
      - Frieren 2mo ago
        > Species die off all the time, This species didn't just die, it was exterminated by humans. It is the difference between someone dying fro a sickness and from a bulled to the head. > overindexing How can be stop fishing species to extinction "too much"? How can you justify that way of thinking in this concrete case?
        CGMthrowaway 2mo ago
  - RobotToaster 2mo ago
    So we need to start hunting shark?
    - M95D 2mo ago
      Start a viral trend and they'll be gone too in 5 years.
  - IAmBroom 2mo ago
    To be fair, we used to catch decades-old (and probably centuries-old) gigantic cod. There hasn't been enough time to rebuild those giant predators back into the system, which has broad effects. It's like clear-cutting an old-growth forest, and then replanting acorns. The forest simply won't return to anything like its original state for many decades - if ever.
  - 2b3a51 2mo ago
    Replying to my own post as well past edit timeout. I can't find anything about niche occupancy replacement at all on the Web. Searches lead to information about the trophic decline in prey species after an initial boom when the North Atlantic cod went down to something like 1% of previous volume. Some mention of harp seals competing with younger smaller cod for available food (which is scarce now apparently). Could be a case of a small effect earlier in the timeline masked by huge changes resulting from warming water &c.
BrtByte 2mo ago
That's the scary part. By the time the data is unambiguous enough for everyone to agree the stock has collapsed, you're already dealing with the collapse rather than preventing it
- karmakurtisaani 2mo ago
  Seems like a pattern with environmental problems.
  - dredmorbius 2mo ago
    Unclear signals and long lag times make systems management a real bear.
    - karmakurtisaani 2mo ago
      Also it doesn't help there are people whose income depend on the system collapsing
      - dredmorbius 2mo ago
        Quite. Perverse incentives, generalising.
- atoav 2mo ago
  Turns out, it is hard to understand a potential future problem if your salary or comfort in the present depends on you not understanding it. Climate change is pretty much the same.
dghughes 2mo ago
And that's with management. Here on the east coast of Canada cod was a big industry and was managed by Dept of Fisheries and Oceans aka DFO. The problem was foreign fishing freezer ships just over the maritime border. They took whatever they wanted to and were no restricted even by their own countries. Canada almost went to war with Spain and Portugal we even sent warships to the area.
CGMthrowaway 2mo ago
Not all fishery crashes are the same. Alaskan sockeye had a huge crash in 2014 which was immediately followed by huge gluts in 2015-2017. Same thing happened last year after a terribly weak run in 2024. Important to look at specific facts and context

rukuu001 2mo ago

Yes, seen this happen in Tasmania, Australia with crayfish, scallops and orange roughy. Each went from free-for-all to highly managed quotas within a few years. Roughy fishing stopped completely back then, don't know what the status is now. > we don't really know much about how fish live and their overall population Absolutely yes. Orange roughy is a good example - it was caught by trawlers when they were massed in huge balls near the surface. Easy to get a big catch quickly. Turns out this was when they were spawning, so breeding cycle was being interrupted, which led to catastrophic declines very quickly.

2b3a51 2mo ago
My understanding is that the cod fishery decline in Atlantic waters has had limited recovery because the ecological niche that the cod fish occupied has been taken over to some extent by a small shark species. The wikipedia page mentions 'trophic cascade' so larger populations of prey species but does not mention the shark takeover. Either way cutting the harvesting won't bring the fish back.
- Frieren 2mo ago
  > because the ecological niche that the cod fish occupied has been taken over to some extent by a small shark species. That is very interesting, I wish this kind of things were taught in school. Too many people think that animals just exists in the current state for ever. When in reality it is a dynamic system that once changed cannot be brought back.
  - Schlagbohrer 2mo ago
    Too many people think food grows on a grocery store shelf. If they've never grown a plant from seed and eaten the result, it is hard to internalize the reality of the supply chain.
  - TeMPOraL 2mo ago
    There are two sides to it. The other side is: what people consider current "balance of nature" is just a transient state. Species die off all the time, ecosystems last millenia and then suddenly collapse, then rebound and look completely different. Protecting the habitability of our planet is paramount, but overindexing on how any particular aspect of it looks at any moment is a fool's game.
    - xyzzy_plugh 2mo ago
      This is true of trees even. People think forests have looked the same for all time but trees are frequently pushing each other out of areas. Disease and pests play a huge role as well. There's some amount of introduced pressure due to invasive species of both trees and pests but it's always been this way. Everything is in flux all the time. Stable pockets exist but they're relatively rare.
    - expedition32 2mo ago
      The planet will literally survive anything. Life finds a way. There were supervolcanoes that blanketed the skies for millions of years. But human civilization as we know it is fragile.
    - Frieren 2mo ago
      > Species die off all the time, This species didn't just die, it was exterminated by humans. It is the difference between someone dying fro a sickness and from a bulled to the head. > overindexing How can be stop fishing species to extinction "too much"? How can you justify that way of thinking in this concrete case?
      - CGMthrowaway 2mo ago
- RobotToaster 2mo ago
  So we need to start hunting shark?
  - M95D 2mo ago
    Start a viral trend and they'll be gone too in 5 years.
- IAmBroom 2mo ago
  To be fair, we used to catch decades-old (and probably centuries-old) gigantic cod. There hasn't been enough time to rebuild those giant predators back into the system, which has broad effects. It's like clear-cutting an old-growth forest, and then replanting acorns. The forest simply won't return to anything like its original state for many decades - if ever.
- 2b3a51 2mo ago
  Replying to my own post as well past edit timeout. I can't find anything about niche occupancy replacement at all on the Web. Searches lead to information about the trophic decline in prey species after an initial boom when the North Atlantic cod went down to something like 1% of previous volume. Some mention of harp seals competing with younger smaller cod for available food (which is scarce now apparently). Could be a case of a small effect earlier in the timeline masked by huge changes resulting from warming water &c.

BrtByte 2mo ago

That's the scary part. By the time the data is unambiguous enough for everyone to agree the stock has collapsed, you're already dealing with the collapse rather than preventing it

karmakurtisaani 2mo ago
Seems like a pattern with environmental problems.
- dredmorbius 2mo ago
  Unclear signals and long lag times make systems management a real bear.
  - karmakurtisaani 2mo ago
    Also it doesn't help there are people whose income depend on the system collapsing
    - dredmorbius 2mo ago
      Quite. Perverse incentives, generalising.
atoav 2mo ago
Turns out, it is hard to understand a potential future problem if your salary or comfort in the present depends on you not understanding it. Climate change is pretty much the same.

dghughes 2mo ago

And that's with management. Here on the east coast of Canada cod was a big industry and was managed by Dept of Fisheries and Oceans aka DFO. The problem was foreign fishing freezer ships just over the maritime border. They took whatever they wanted to and were no restricted even by their own countries. Canada almost went to war with Spain and Portugal we even sent warships to the area.

CGMthrowaway 2mo ago

Not all fishery crashes are the same. Alaskan sockeye had a huge crash in 2014 which was immediately followed by huge gluts in 2015-2017. Same thing happened last year after a terribly weak run in 2024. Important to look at specific facts and context