There's no denying that keeping livestock has deeply benefited humanity over the millennia. But, while sheep and cows may have adapted well to farm life, there's one animal humans like to eat that would fare poorly in farms.

Octopuses, scientists have argued in a new essay, should never be farmed - not just because of their intelligence, but because of the environmental impacts such farms would create.

It's already started. Global demand for octopus as a food is on the rise, which last year saw prices soaring amid poor supply. Prices are expected to remain high for at least the rest of 2019.

The yield of octopuses fished in the wild is variable, which in turn contributes to an unreliable supply - hence attempts to farm octopuses have already commenced. In multiple countries around the world, efforts are underway to produce an octopus farm, including trials of genetic modifications to accelerate cephalopod aquaculture.

This, of course, would produce some known environmental impacts, a team of environmental scientists, philosophers and psychiatrists writes in a recent edition of Issues in Science and Technology.

Such impacts include nitrogen and phosphorus pollution from animal waste, interbreeding and the spread of disease, and loss of habitat, to name a few.

But the biggest environmental concern is the octopus diet. Like most farmed aquatic creatures, they're carnivores, and need fish protein and oil in their diet. And octopus larvae only eat live food - that has to come from somewhere.

"Feeding most farmed aquatic animals puts additional pressure on wild fish and invertebrates for fishmeal," the researchers wrote.

"Around one-third of the global fish catch is turned into feed for other animals, roughly half of which goes to aquaculture. Many fishmeal fisheries are subject to overfishing and are declining."

Octopuses need a lot of food - at least three times the weight of the animal over its lifetime - and making sure their needs are met in factory farms would create more, not less pressure on these already declining fisheries. This would likely decrease global food security for humans.

But, even if this problem could be solved, keeping octopuses in factory farms would be cruel.

If you've ever been to a marine aquarium, you likely know this. Octopuses are well known for their intelligence and problem-solving skills. Toys are often kept in the octopus tanks to keep the cephalopods from getting bored.

They can open jars, recognise individual humans, remember puzzles they've been given before, even escape an aquarium when they've had enough (so, you know, that's a consideration too - imagine an entire farm of octopuses making a jailbreak).

They've also shown worrying behaviours in captivity, including cannibalism, and eating the tips of their own tentacles (which could be the result of an infectious disease). In an environment with no stimulation, these animals grow frustrated and bored.

"Beyond their basic biological health and safety, octopuses are likely to want high levels of cognitive stimulation, as well as opportunities to explore, manipulate, and control their environment," the scientists wrote. "Intensive farm systems are inevitably hostile to these attributes."

At the moment, there are some pretty big challenges to overcome even getting an octopus farm off the ground, such as keeping the young animals alive through to adulthood. But technological advances could see that change.

Research is surging ahead around the world. Octopus farming experimentation in Mexico has reported breakthroughs in the last decade, and a Japanese seafood company has reported successfully hatching eggs in 2017. They have predicted they'd have farmed octopus on the market next year.

With so many problems already evident, the scientists are hoping this can be nipped in the bud.

"It is our hope that if such an option does become practical, society will recognise the serious welfare and environmental problems associated with such projects and octopus farming will be discouraged or prevented," they wrote.

"Better still would be for governments, private companies, and academic institutions to stop investing in octopus farming now and to instead focus their efforts on achieving a truly sustainable and compassionate future for food production."

The essay has been published in Issues in Science and Technology 35.