An octopus unscrews the lid of a jar to get hold of the crab inside, in an aquarium in Denmark (Picture: Jorgen Jessen/AFP via Getty Images)
Masters of camouflage, their skin is embedded with cells that sense light, giving them an array of tricks for thwarting enemies. They can match the colours and textures of their surroundings, enabling them to become near invisible. They can escape at speed by shooting forward with jet propulsion. They can squirt ink to hide themselves and dull the senses of attackers. And if they lose an arm, they can grow it back.
As ethologist Dr Jane Goodall observed, octopuses are highly intelligent and able to do extraordinary things. Wild octopuses have been known to carry coconut shells with two tentacles and walk across the ocean floor with the other six, whereupon “they put down half the shell and ooze their body into it because they are very soft-bodied and can get into tiny spaces. Then they reach out and put the other half over them. They’ve made a house!”
Octopuses are curious, explorative problem-solvers with long memories. One study found they remembered how to open a screw-top jar for at least five months. They can also show a sense of craftiness, squirting water at researchers they don’t like.
One celebrated aquarium-kept octopus became renowned when staff noticed that fish from a neighbouring tank had gone missing overnight. CCTV revealed that the octopus was lifting the lid of his tank, slithering over to grab the fish and then crawling back, before returning to the tank and putting the lid back on as if nothing had happened.
A gourmet food
As global stocks of fish decline, demand for octopus is increasing, yet their numbers are coming under strain. Overfishing, combined with growing demand, is driving prices up, leading to burgeoning interest in octopus farming.
It has been fished for centuries, but the numbers caught almost doubled from 180,000 tons in 1980 to more than 350,000 tons in 2014. In Australia, octopus has gone from accidental catch to a gourmet food so quickly that the fishing industry has been unable to keep up with demand, further throwing a spotlight on the potential for aquaculture.
Octopus ranching is being tried in Australia and Italy, with research underway in Portugal and Greece. A farm in Mexico’s Yucatán Peninsula has reportedly successfully farmed the Maya octopus, with experimental farms set up in China and a Japanese company, Nissui, hatching octopus eggs in captivity.
Aggression and cannibalism
One previous problem for the industry was how to keep these intelligent, inventive creatures confined in a tank, given their habit of hurling themselves out. Neither heavy steel mesh nor electric fences were enough to prevent them escaping. Placing woven cloth around the tank’s edge eventually stopped them; their suckers couldn’t gain a grip on the porous material.
In the wild, octopuses will go to great lengths to defend their patch, a behaviour that limits the number that can be reared in a given space. In a farmed environment, with lots of animals in a sterile tank, things can quickly become fraught, leading to aggression and cannibalism. Researchers have overcome this problem by providing each octopus with a plastic tube to hide in, though that limits the number of creatures they can cram into a tank.
At a model farm in Western Australia, researchers found that aggression was reduced when they kept individuals of the same size in a tank, with no need for plastic hides. This made cleaning the tanks easier and meant they could keep more than triple the number of octopuses in each tank. The lead researcher Dr Sagiv Kolkovski reportedly said: “We added so many to the tanks that we had to install flat PVC sheets so they would have more surface to attach to, as the tank walls were completely occupied.”
Growing scarcity
However, there were still huge problems to overcome: no one knew how to rear octopus in captivity past the larval stage, or how to provide the right nutrition and environmental conditions to grow larvae. The breakthrough came in 2019 when the Spanish Nueva Pescanova Group announced that common octopus born in confinement had not only been reared to adulthood, but one of them had gone on to produce eggs. It was sufficient progress for the company to announce it expected to be selling farmed octopus by 2023.
The company added that its pioneering work was in “response to the high international demand”, which had “caused a growing scarcity of wild octopus and, therefore, a sustainability problem in the marine environment”.
Amid the rush towards farming, fears grow about the likely impact on the marine environment. Octopus eat small fish and other marine life; their diet in aquaculture will most likely consist of fishmeal made from fish eaten by bigger fish, birds and marine mammals.
So rather than protecting the oceans, the farming of carnivorous species like octopus, as well as salmon and trout, puts yet more pressure on the oceans. When one starts thinking of them as individuals with personalities or indeed, after watching Netflix’s My Octopus Teacher, most people would be upset by the plans to confine and farm these fascinating, inquisitive and sentient creatures. As intelligent, complex animals with large cognitive capacities, their lives would simply not be worth living.
At a time when we urgently need to protect biodiversity and the beauty of our natural world, there can be no doubt that major health and welfare risks are created when animals are kept in ways that fail to meet their natural needs or properly mimic their wild environment.
The farming of octopuses seems completely at odds with everything we understand about this species and everything we know that is morally and ethically right.