The answer is 1/7.
1/7 of the calories needed to grow the amount of protein, that a cow needs.
They dont need to heat themselves up. They dont need to build large bones to fight gravity. Sorry, i know its not cool to be for something nowadays, fish farming of all the farming, has the best ratio.
Aquaculture has the best ratio, but fish farming isn't the only way to do it.
The GreenWave folks seems to have a decent alternative. They base their aquaculture on filter feeders (oysters, mussels, scallops, clams) and autotrophs (ocean kelp, a salad green which btw is the source of omega-3 in fish), with the result that their farms clean up fertilizer runoff from terrestrial farms and reduce eutrophication. Their protein requirements are even lower than fish farms, requiring 0/7ths of what a cow needs (ie no inputs).
To be fair, chinese do exactly the same since 1950, when they invented and polished the modern polyculture systems based in seashells, ocean kelp, and crabs or fishes (and a similar freshwater version since thousands of years ago). Culture of marine filter feeders is not exactly breaking news for spaniards, french, dutch or japanese. If you can't resist the urge to invest on them, remember that GreenWave is just another company doing the same as thousands of current asian and european companies. Would be not much different than claiming that a californian company invented wine in 2017.
Attribution aside, I'd like to see the technique more widely known and practiced. The commenter was defending fish farming by favorably comparing it to cows, but ignored shellfish polycultures probably because they simply didn't know about them.
It appears to be mainly China that practices it widely. To the extent the Chinese aren't scaling it globally as a climate-friendly alternative to fish farming, they leave an opportunity for other players.
And to come back to the topic of the original post: there's an invasive species of Japanese oysters in the Dutch Wadden Sea that you're free to harvest if you're in the neighbourhood. Although the debate on whether they are an ecological disaster or help restore the environment is not set, it's probably going to be the former if left unchecked, so you'll probably be helping out in the process.
I recall that there is a general recommendation to have a max limit on the amount of filter feeders in a diet because they have an above average in toxins and heavy metals. There have been suggestions to use such animals to explicitly clear out runoff from terrestrial farms and industries, but then the toxic levels would be so high that the meat is no longer be suitable for human consumption.
That said, they are a delicious source of food that is superior to other meat in many aspect, including being very ecology friendly and space efficient. Anyone that is trying to minimize the damage that a diet has on the environment should consider adding them.
In France, where there are a lot of oyster and mussel farms along the Atlantic coast (apparently, modern oyster farming was invented there in the mid 19th century) warnings and restrictions are regularly issued because of pollution from natural or land farming-related causes, or mollusc diseases.
Shellfish farming is very efficient and ecological, in addition to having cultural value as a traditional local activity, but it does have drawbacks.
I'm having a hard time finding official advice to avoid shellfish that doesn't advise avoiding fish too[1]. In fact, the FDA lists scallops, clams, shrimp, and oysters as having the lowest amount of mercury[2].
It looks like some shellfish toxicity is due to cyanobacteria[3], which is mostly caused by eutrophication from farm runoff. But scaling this system should help with that.
You didn't explicitly state this, but I think it's important to highlight: protein != meat. Farming fish is more efficient than farming cows, but it's still more wasteful than having people eat plants directly.
It seems to me that a lot of damage is being done because of the idea that getting enough protein is difficult unless you eat meat. In reality, it's difficult to be protein deficient if you eat 2000+ calories/day.
I'm not advocating that everyone go vegan, but clearly the amount of meat we eat today is unsustainable. I think a good first step to addressing that is some nutrition education, and dispelling the myth that protein = meat.
A plant based diet does not eliminate ecological stress. The requirements for oil and petroleum skyrockets due to the need for nitrates and fereralizers . The only real solution without a ecological impact is reducing world population.
We use land/nitrates/fertilizers to grow crops to feed to cows/pigs/chickens/fish, which convert those plant calories into fewer meat calories. If we ate more plant-based foods, we'd need to grow less, not more.
I understand this is simplistic, as some plants (e.g., iceberg lettuce) provide few calories and are costly to grow. On average, eating from trophic level 1 is more efficient than eating from levels 2 or 3.
Cows need to live a long time, which costs a lot of energy. Chickens are much closer to fish, but eggs are even better in terms of grain calories to protein conversion.
PS: Salmon on the other hand are horrible as predators they cost more protean than they produce.
I am not sure, scientifically speaking, what a statement like "All predators cost more protein than they produce." means or why it is significant. Can you provide a citation to this?
Humans are omnivores so while we can live off plants it's much easier to have a healthy diet if you eat some animal protean. Generally people prefer not to eat bugs / 'trash fish' etc, even if we can digest them just fine. So, we generally feed that stuff to farm animals like cows but also farm fish.
The problem is people want more meat than we get just from feeding trash fish to chickens. So, we also use farm grown plants like corn. But, salmon can't eat corn. So we would need another step say corn > bugs > salmon. And it's more efficient to go corn > chickens than corn > bugs > salmon.
So, now we are better off feeding some corn to some chickens. But, we can also feed those 'trash fish' to chickens to speed their growth. And it turns out it's also more efficient to feed chickens a mix of corn + 'trash fish' than it to use that same corn to feed some chickens and all of the 'trash fish' to feed salmon. The reason for this is chickens use much of the protean in their diet to build protean in them, but salmon also use protean in their diet for energy.
Think he is referring to trophic levels. There is at least one order of magnitude more energy and resources needed going from one level to the next. So I think he is saying you should eat fish that don't eat other fish mainly.
I find I have to starve myself to be productive once I eat, it's over. At least milk/cereal/something heavy.
Beans, maybe a good recipe slow cook... Eaiser than buying those cheap thin pizzas from Walmart for $3.99, damn ate three of them today. Was hating myself, then after hours later agonizing, I got up, solved this code problem and boom! I feel better about myself.
Granted I'm in my 20's upper abs visible, v body but family's dying by heart problems. Evolution man self correcting mechanism.
I was eating those fake sausages (green boxes) for a couple of weeks with brocolli man they're expensive. Rice is so filling too I realize.
