The Deep Scattering Layer and Oceans Dying Off

[Cikomyr2]

So through a meme I recently learned about this "Deep Scattering Layer". Basically a layer that caused sonars to assume the bottom of the ocean wasn't as deep as expected.

and that layering turned out to be a MASSIVE amount of fish. In fact, from what I've seen, this layer represents about 65% of all deep sea fish biomass, so we now know there's a ****ton more fish than we previously estimated.

How does that play in the whole "fishes are dying out" stories I have been reading in the past years, related to climate change and acidification of the oceans? Does this fish layer change some of our assumptions regarding the resilience of the earth's oceanic life? Do we know if this Deep Scattering Layer of fishes acts as some sort of strategic reserve of biomass?

[Eldan]

I mean… mostly speculation, but...

"Biomass reserve" is not really a thing? Just because there's biomass in one habitat doesn't mean a neighboring habitat can't die out. Deep sea fish won't suddenly migrate up if the surface fish die out.

Additionally, one would assume that These fish would die out too. Maybe not at the same rate. Perhaps their Depth insulates them, but if the Ocean acidifies further and transfer of nutrients with upper layers changes, eventually, that's going to have an effect.

[Tvtyrant]

Imagine if the issue was all of the forests we know of were dying to a beetle infestation. Unexpectedly we find a massive forest we didn't know about. Would this suddenly discredit the beetle infestation theory?

We don't know if the Lantern Fish/Tree population is in decline as well, because we don't know what it started at. All we can really know is there was an unexpectedly large population of fish.

[tomandtish]

It's also important to note that this is not a recent discovery. Even by the end of WW2 they knew they were getting false readings caused by animal life. It may have taken a while to figure out how much more sea life, but we've known it was there for quite a while. Heck, the encyclopedias my grandmother left me (from the mid 60s) talk about it.

[halfeye]

So through a meme I recently learned about this "Deep Scattering Layer". Basically a layer that caused sonars to assume the bottom of the ocean wasn't as deep as expected.

and that layering turned out to be a MASSIVE amount of fish. In fact, from what I've seen, this layer represents about 65% of all deep sea fish biomass, so we now know there's a ****ton more fish than we previously estimated.

How does that play in the whole "fishes are dying out" stories I have been reading in the past years, related to climate change and acidification of the oceans? Does this fish layer change some of our assumptions regarding the resilience of the earth's oceanic life? Do we know if this Deep Scattering Layer of fishes acts as some sort of strategic reserve of biomass?

Most of the fish dying is because people eat too many. Given enough years of less or no fishing, the cod and herring would come back, but it's not likely to happen.

[Tyndmyr]

and that layering turned out to be a MASSIVE amount of fish. In fact, from what I've seen, this layer represents about 65% of all deep sea fish biomass, so we now know there's a ****ton more fish than we previously estimated.

That makes sense. If you go fishing, even in freshwater, you can sometimes see similar effects. Fish can stack up like cordwood in favorable circumstances, and usually naturally prefer to school.

Usually, when we talk about fish shortages, we're not talking about all life, but rather about specific species. Perhaps the Tuna in one environment is being overfished or something. That's very different from wiping out all life, but from the perspective of someone who wants to eat some tuna, it's still an issue.

If we fish out the game fish, and are left with only the fish that people would prefer not to eat, we have still changed the environment in a way that leaves it less suited for us. It is deeply unlikely that humans can actually wipe out life on earth. However, we can absolutely make things worse for ourselves.

[Eldan]

I mean, tuna is probably going to die out, unless we find ways to farm it. People are working on that. Large tuna is already basically gone.

[halfeye]

I mean, tuna is probably going to die out, unless we find ways to farm it. People are working on that. Large tuna is already basically gone.

Blue fin Tuna? yeah, in deep trouble. Mackerel? a bit troubled but breed very fast and may be holding out despite being massively overfished.

[farothel]

Or we have to learn how to eat the things that are abundantly present. Like those chinese mitten crabs that are infesting waters here (they probably arrived in the ballast tanks of ships). They're edible, but the problem at the moment is that they take on massive amounts of pollutants from the bottom of the rivers.

One of the main issues is that we humans eat from both the top and the bottom of the food chain. And take the occasional nibble in the middle as well.

[Bohandas]

I mean, tuna is probably going to die out, unless we find ways to farm it.

Or regulate catching it in a way that isn't merely nominal

[Eldan]

Or regulate catching it in a way that isn't merely nominal

Heh. Good one.

[sktarq]

I mean even fishes we think of massive breeders....3 million eggs per year in a large female for example can collapse hard with enough pressure (Cod)....so I don't anything is safe. And bycatch is such a major killer of ocean life we don't even eat (and most of that we don't even turn into fishmeal) that I seriously think that most oceanic species are on the chopping block.

[halfeye]

I mean even fishes we think of massive breeders....3 million eggs per year in a large female for example can collapse hard with enough pressure (Cod)....so I don't anything is safe. And bycatch is such a major killer of ocean life we don't even eat (and most of that we don't even turn into fishmeal) that I seriously think that most oceanic species are on the chopping block.

Yeah, it wants sorting, and national governments mostly won't do it because "Mine: you can't have any".

What will be worse is when we start eating the small fry that the bigger fish need as food, thus far whitebait are as small as we go, but there are sandeels, krill, lantern fish and plankton below them, and when those go, nothing lives.

[sktarq]

Hey I look forward to my Seabars^TM they come in so many fun flavors like copepod, sea jelly, algae, diatom crunch, krill, and microbe-mat!! Sea Jelly is my personal favorite. [/s]