And also, what interventions can be done to increase the amount of human-digestible calories (as well as various nutrients) in the ocean that would be available after some global catastrophe?
Actually, similar questions also apply for other calorie sources. For example, maybe eating insects is good on utilitarian grounds because it encourages the insect industry which can more easily continue to thrive even if the Sun gets blocked.
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You’ve also suggested that we eat bacteria. How would that work?
There are two main sources of bacteria that we looked at. There is a methane-digesting bacteria that you basically grow on natural gas. And then we can either eat that directly or process it or say, feed it to rats and then eat the rats. Then there’s the bacteria that we can grow directly on wood. Or on leftover mushroom waste. And so this would be taking down a tree, pulverizing it, turning it into a slurry, and then letting the bacteria go at it.
So for instance, there are bacteria that secrete sugars they then use to feed themselves. You can pull out the sugars, and eat those ourselves and leave the bacteria and the partially decaying wood pulp. And we can feed that stuff to other things. So for instance, rats digest wood to some degree, particularly after it is partially broken down that way. This makes a fairly good solution. We could feed something similar to chickens. And chicken is something maybe people would maybe be happier to eat than bacteria milkshakes.
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(source: http://nautil.us/issue/101/in-our-nature/what-to-eat-after-the-apocalypse )
I agree it might be an important moral harm to create all those insects, but if the above premise is true, then the extinction resilience aspect seems more important (because if we go extinct, wild insects will likely continue to be created for the next ~5 billion years).
Some information I found
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Could the oceans feed us?
If you looked at the amount of fish that we currently eat, it’s just a tiny fraction of the human diet. You can expand that much more without wiping out all the fisheries. If you have significant climate change, that will result in more upwelling [seawater rise from the depth of the ocean to the surface], which will be like fertilizing the ocean surface, and you get more fish. Similarly we can purposely fertilize the ocean in order to get more fish. So then we have enough fish to feed everyone. How do you catch it all?
Then we started to look into how many ships exist—and if we converted all of them to fishing vessels, would that be enough in order to get enough fish harvested to meet demand? It turned out you end up with problems such as round trip distance. You can’t have little fishing boats go out and fish and then drive all the way back. The solution to that is ship-to-ship transfers of fish, which luckily, they already do now. So our fish solution is actually one of the better ones under certain circumstances. [But] it won’t work for everything. You still need some light.
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http://nautil.us/issue/101/in-our-nature/what-to-eat-after-the-apocalypse
Thanks for your interest—all of ALLFED’s published research is here. But what is not yet published is that it is looking like the ocean fertilization effect will not be as strong as we had originally estimated. However, there are ~10 billion tons of deeper water fish (200 to 1000 m down), though they would be expensive to harvest. We think producing seaweed would be low cost and feed many people.
I’ve read 80% of Feeding Everyone No Matter What, and they cover all sorts of alternative food sources we could use in the event of a global catastrophe. These include seaweed, mushrooms, insects, bacteria, and more. Have you been able to read it?
I haven’t tried to. any section answering my question? (or) are you implying we shouldn’t care about reducing the food supply in the oceans given the amount of alternatives we have?