Tuna are spawning in marine protected areas | Hacker News Reader

Tuna are spawning in marine protected areas

news.mit.edu

140 pointsel_duderino28 comments

To show my kids a bit about programming we made a simple rabbits-and-foxes simulation. Little dots moving around a rectangle drawn on the screen. The red ones were rabbits, would move mostly randomly, and would periodically make a baby rabbit. The blue ones were foxes and would chase nearby rabbits. When they caught one they'd eat it and make a baby fox.

Fun to watch but we found no matter how we set the initial counts of rabbits and foxes, inevitably there'd be a population spike of rabbits, which would cause a lot of foxes to be born, which would eat enough rabbits (sometimes ALL of them) that the rest of the foxes would starve and go extinct.

We tweaked all kinds of parameters about how they move and how they reproduce and nothing kept the system from oscillating into a broken state.

Eventually we added a "rabbit preserve" - an area rabbits could pass freely through but foxes couldn't enter. Just like that - the system was stable(ish). There would still be population peaks and valleys but as long as the preserve was reasonably large the rabbit population might crater but wouldn't crash.

Its a nice little project, easy to code and fun to watch

Fox predators, aging, and/or direct competition (fighting) could be an interesting lesson in dampening feedback to reduce those oscillations.

Simulating grass carrying capacity, other herbivore competition, different predator niches, etc all further increase stability / resilience to change.

Add earthworms. ;- )

Is this a joke or reference, perhaps?

My understanding is that lion prides are territorial, but the herds they prey on are not. The prides with prey in their territory eat; those without starve.

This sounds similar to the “preserve” system that you’ve hit upon, except that the preserves change location over time based on the number of predators, and the prey group into herds.

Heh, this reminds me of The Matrix an Zion.

At secondary school, probably around 1998 or so, there was a Windows desktop program called, I think, "Creatures".

...and I've actually found it, via a 2001 book for school science teachers [1], which leads to archive.org [2] which even has the .exe to download.

Before we had internet access on every computer, this was one of the more fun things to play with on the school computers.

You can see it's possible to adjust the sunlight, grass death rate, fox hunting ability, rabbit death rate and fox death rate. The "Disasters" menu had things like "Meteorite blocks sunlight" or "virus spreads through foxes"; these were often fatal unless the parameters were perfect.

[1] https://books.google.dk/books?id=8W3XJkeF9WUC&lpg=PA91&ots=J...

[2] http://web.archive.org/web/20041116110431fw_/http://www.fssc...

If you simulate the food chain more by making the rabbits compete for food (green dots) and the fox birth rate much lower than the rabbits / add starvation to the equation (blue dots that don't eat rabbits with enough frequency disappear) you can capture the Apex predator effect too. Too few foxes and you'll see your rabbits eat all the green and the system similarly collapses.

So by not fishing at all in the protected 11% portion of their fishing area, they're projected to get more fish due to the spillover effect. Well, no surprises there.

We rarely ever do these economic projections.

They can apply to so many more areas, like the forests in Indonesia where they're discovering new antibiotic compounds in shrubs, or the spider habitats whose venom is used in producing heart medication, they're probably a lot more expensive than some lumber and cornfields.

I feel like if we communicated environmental protection more materialistically instead of emotionally, people would have an easier time convincing their politicians to actually enact it.

If we're gonna calculate 25-30 year mortgages for homes than we should probably do environmental risk projections too in dollar figures for those kinds of time frames.

One argument against this position is that economic environmentalism cuts both ways. Sure

Sure, marine preserves produce an economically beneficial surplus of salmon. Also, the oil reserves in the Arctic national wildlife refuge are worth more than 500 billion dollars.

In the case of Arctic drilling, I think the moral argument against destroying wilderness is the only viable option.

There is a strong economic argument for keeping oil in the ground now, though. Namely, that the planet will cease to support a functioning global economy under runaway warming.

That oil could theoretically be burned and the carbon sequestered. Hence no climate impact.

The hazard to fragile ecosystems from an industrial accident is still huge.

Edit: the point is that some environmental protection actions have to be driven by moral/ethical forces. We can't leave everything to the economy.

Having said this there might be ways to use market forces to implement the ethically required environmental protections.

Well, if they can afford to pay market-rate insurance on the liability of their sequestration method then yeah sure.

Interesting thought. I know nuclear plants are required by law to set aside a part of revenue for eventual long term storage of the waste. You could have that for coal plants.

Of course we already have quotas and trade which is designed for something similar.

And the offsets have their problems...

This can apply here too.

The amount of oil that can be safely burned is finite. Meaning there's only so much air to burn, and it should be auctioned off at market value, thus it gets more and more expensive over time. We pay for garbage disposal, why not pay market rate for carbon disposal too, it's the most capitalistic and scalable way to solve the problem.

Instead of trying to have this type of accounting many lobby to simply not pay for it because it would make their business less competitive with other energy businesses.

As for the alaskan wilderness, that could become profitable farmland or residental area later on as the climate warms. Being a wilderness experience would increase the value of the real instead whereas being oil contaminated would make it a lot less desirable.

I don't think the problem is not knowing that one in a million spiders in the nearby jungle could cure cancer, it's the knowing that once someone finds the spider they'll take it, get rich, and leave you with 999,999 poison spiders.

If you torch the jungle and grow stuff maybe you could get rich, or at least get rid of the spiders.

> The researchers observed multiple species of tuna larvae throughout this protected expanse

Somehow I've gone over 40 years without realizing that fish have a larval stage.

You haven’t heard of caviar? (-:

Yup, reproduction in fishes is "imaginative", sex is complicated and things can turn bizarre easily.

https://australianmuseum.net.au/blog-archive/science/large-m...

I'm in the same boat, I assume like me you were thinking of larvae and maggots as being synonymous, but it looks like with fish the larval stage is more tadpole like: https://en.wikipedia.org/wiki/Ichthyoplankton

I knew of tadpoles, and I knew fish eggs, but somehow I guess I just imagined fish hatching as tiny fish.

This is the original article. It's open access!

I'm surprised MIT's press release doesn't link to it.

https://doi.org/10.1038/s41598-019-47161-0

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