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I don't think the data supports the notion that there is a collapse. A lasting 70% reduction without the ongoing interference (overfishing) by humans would be a

I don't think the data supports the notion that there is a collapse. A lasting 70% reduction without the ongoing interference (overfishing) by humans would be a problem, but even that would not be a collapse. A couple decades ago the concept of overfishing became more well-known, and the industry was forced to change. The reason that the industry reacted also has to do with the fact that a true collapse of the fish population would also decimate the entire industry - they have an interest in keeping it stable. If 99% of a fish population goes away, it would take decades for the population to recover to normal levels. During those years, there would be no profit. The true reason why the fish population is down 70% is due to the fact that every year the fishing industry takes out as many fish as possible without causing a lasting depression of fish population. If all fishing would be stopped right now, the global fish population would recover to pre-human levels within probably 20 or 30 years. Here's what someone from the Australian fishing industriy has to say about this: "We have learned from the ’60s to ’90s era and today most large fisheries are well managed (some in Asia/Africa are not) and either recovering or operating at maximum economic yield. You cannot catch fish to extinction – they will always recover if you stop fishing. It’s the recovery time that is the issue – and the time to when you can recommence harvesting, sustainably." Of course these people are heavily biased, and the industry is rotten to the core and full of corruption, but it's hard to argue against this self-evident logic.

bch 4y ago
> I don't think the data supports the notion that there is a collapse. It’s not a collapse of “the ocean”, but: https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_northwest_cod_fishery https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_north...
fallingfrog 4y ago
How do you know this? OP states that their statement comes from marine biologists.
- MilesCe 4y ago
saiya-jin 4y ago
That all relies on the fact that all actors involved have some shiny long term sustainability goals and behave strictly morally. Which as all know damn too well is a pure fantasy. Chinese fleets swiping parts of oceans clean anywhere they can and are not caught couldn't care less what will be there in 50 years, or some treaties of western countries. Also, you completely ignore 2nd and 3rd order effects - decimation of populations dependent on those missing fish that can't and won't recover as easily as fish can.
- MilesCe 4y ago
tablarasa 4y ago
You might find this paper interesting- it's focused on adapting fisheries management to climate change, but some of the core principles of fisheries management are touched [1]. Check out some of the figures. There are some paradoxical concepts in fisheries management, not least is that the Maximum Sustinable Yield often supports aligned interests between fisherman (who want to profit/eat) and fish populations (who want to persist). Overfishing is a tragedy of the commons; managing those fisheries properly can produce MORE fish in the ocean even if yields go up. Not always, but this stuff is not cut and dry and the dynamics of population growth and extraction in these animals have to be understood. [1] https://www.science.org/doi/10.1126/sciadv.aao1378 https://www.science.org/doi/10.1126/sciadv.aao1378
heisenzombie 4y ago
That's fine if your population model is just an independent logistic function for each species. But ecosystems aren't like that. I'll take an example from New Zealand because it's where I live and what I know about. New Zealand has a huge fishery EEZ and is, I believe, widely regarded has having one of the most "well managed" fisheries in the world. And yet, in large parts of our inland waters a combination of soil runoff and bottom trawling has turned millions of acres of seabed from incredibly productive nurseries of seagrass beds and shellfish-covered rocky reefs... into featureless swathes of sediment called "Kina barrens" (basically, dominated by a kind of spiky sea-urchin). These areas have passed a tipping point, there's basically no getting them back. Shellfish can't attach to the mucky sediment to regenerate the reefs or filter the water, and seagrass is instantly eaten by the sea-urchins, which run amok because there's no nursery for the snapper population that would normally keep them in check. I don't know what my point is, really, other than to say that I think it's hubris to think we have a sophisticated enough understanding of ecosystems to balance thousands of species on the knife-edge of fishing them to maximum sustainable pressure. Sometimes we'll get it wrong and an ecosystem will go "pop". Then we can't get it back. As for positive prescriptions -- The main thing I've heard is that we should be urgently pushing for marine reserves. And that they absolutely have to be large and NO-TAKE. The goal should be something wildly optimistic like 50% of EEZs. Fishing can happen in the other half. (For reference here's where we currently are: https://www.researchgate.net/figure/Map-of-no-take-areas-and-no-take-zones-within-larger-multiple-use-marine-protected-areas_fig3_285402181 https://www.researchgate.net/figure/Map-of-no-take-areas-and... )
wanderr 4y ago
I'm responding to your other claim further down that got downvoted into oblivion with no responses, and therefore no explanation. You are quite wrong, but you deserve to know why. "It's basic school knowledge that any population will recover, as long as you have a couple organisms left who can reproduce and the environment itself hasn't fundamentally changed." I just recently took a biology class, and that is fundamentally not the case. One of the major causes of population collapse leading to extinction is lack of genetic diversity once a population is small. Once diversity is too low, even if conditions are relatively favorable, a population is much more vulnerable to disease or seemingly small changes to the environment. One of the ways biologists try to "rescue" populations these days is by introducing genetic diversity where possible.

bch 4y ago

> I don't think the data supports the notion that there is a collapse. It’s not a collapse of “the ocean”, but: https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_northwest_cod_fishery https://en.wikipedia.org/wiki/Collapse_of_the_Atlantic_north...

fallingfrog 4y ago

How do you know this? OP states that their statement comes from marine biologists.

MilesCe 4y ago

saiya-jin 4y ago

That all relies on the fact that all actors involved have some shiny long term sustainability goals and behave strictly morally. Which as all know damn too well is a pure fantasy. Chinese fleets swiping parts of oceans clean anywhere they can and are not caught couldn't care less what will be there in 50 years, or some treaties of western countries. Also, you completely ignore 2nd and 3rd order effects - decimation of populations dependent on those missing fish that can't and won't recover as easily as fish can.

MilesCe 4y ago

tablarasa 4y ago

You might find this paper interesting- it's focused on adapting fisheries management to climate change, but some of the core principles of fisheries management are touched [1]. Check out some of the figures. There are some paradoxical concepts in fisheries management, not least is that the Maximum Sustinable Yield often supports aligned interests between fisherman (who want to profit/eat) and fish populations (who want to persist). Overfishing is a tragedy of the commons; managing those fisheries properly can produce MORE fish in the ocean even if yields go up. Not always, but this stuff is not cut and dry and the dynamics of population growth and extraction in these animals have to be understood. [1] https://www.science.org/doi/10.1126/sciadv.aao1378 https://www.science.org/doi/10.1126/sciadv.aao1378

heisenzombie 4y ago

That's fine if your population model is just an independent logistic function for each species. But ecosystems aren't like that. I'll take an example from New Zealand because it's where I live and what I know about. New Zealand has a huge fishery EEZ and is, I believe, widely regarded has having one of the most "well managed" fisheries in the world. And yet, in large parts of our inland waters a combination of soil runoff and bottom trawling has turned millions of acres of seabed from incredibly productive nurseries of seagrass beds and shellfish-covered rocky reefs... into featureless swathes of sediment called "Kina barrens" (basically, dominated by a kind of spiky sea-urchin). These areas have passed a tipping point, there's basically no getting them back. Shellfish can't attach to the mucky sediment to regenerate the reefs or filter the water, and seagrass is instantly eaten by the sea-urchins, which run amok because there's no nursery for the snapper population that would normally keep them in check. I don't know what my point is, really, other than to say that I think it's hubris to think we have a sophisticated enough understanding of ecosystems to balance thousands of species on the knife-edge of fishing them to maximum sustainable pressure. Sometimes we'll get it wrong and an ecosystem will go "pop". Then we can't get it back. As for positive prescriptions -- The main thing I've heard is that we should be urgently pushing for marine reserves. And that they absolutely have to be large and NO-TAKE. The goal should be something wildly optimistic like 50% of EEZs. Fishing can happen in the other half. (For reference here's where we currently are: https://www.researchgate.net/figure/Map-of-no-take-areas-and-no-take-zones-within-larger-multiple-use-marine-protected-areas_fig3_285402181 https://www.researchgate.net/figure/Map-of-no-take-areas-and... )

wanderr 4y ago

I'm responding to your other claim further down that got downvoted into oblivion with no responses, and therefore no explanation. You are quite wrong, but you deserve to know why. "It's basic school knowledge that any population will recover, as long as you have a couple organisms left who can reproduce and the environment itself hasn't fundamentally changed." I just recently took a biology class, and that is fundamentally not the case. One of the major causes of population collapse leading to extinction is lack of genetic diversity once a population is small. Once diversity is too low, even if conditions are relatively favorable, a population is much more vulnerable to disease or seemingly small changes to the environment. One of the ways biologists try to "rescue" populations these days is by introducing genetic diversity where possible.