Controversial plans to develop the world's first commercial octopus farm have prompted concern from campaigners and scientists over the welfare of the highly intelligent creature.
The invertebrates are renowned not only for their unique body shape and ability to change colour, but for an impressive brain power said to rival that of cats.
Experts fear intensive farming methods – to produce up to a million octopuses every year for food – could be cruel and put the animals at greater risk of disease.
Long-standing proposals to develop the complex in Las Palmas in Gran Canaria, one of the Spanish Canary Islands, have been the source of fierce debate for years.
Animal welfare activists have suggested the conditions in which the creatures could be kept – said to involve communal tanks – would lead to lack of stimulation and be stressful for animals that live alone in the wild.
To mark World Octopus Day this month, campaign groups wrote to the Canary Islands authorities urging them to reject an application to build the farm.
Among the researchers opposed to the plans is Prof Andrew Knight, a veterinary surgeon and adjunct professor of animal welfare at Griffith University in Australia. He said certain characteristics of octopuses made the plans "particularly concerning".
"They’re highly intelligent," he said. "They’re used to living in a complex environment, manipulating their environment with their tentacles. They’re known for figuring out how to open glass jars … they’re able to solve problems they’ve not previously encountered."
Prof Jonathan Birch, who leads the Foundations of Animal Sentience Project at the London School of Economics, highlighting the challenges of achieving high welfare standards due to octopuses being highly intelligent as well as being solitary and aggressive in the wild.
Added to this, he said, is that the process of farming them is new.
Octopuses can feel pain
Prof Birch and colleagues have sifted through academic studies and concluded that research shows octopuses can feel pain, which raises concerns about slaughter methods that reportedly could include immersing the creatures in ice slurry.
"Killing octopuses by immersing them into ice slurry may well cause pain and doesn't meet expectations for humane slaughter," Prof Birch said.
"When we reviewed the available evidence in 2021, we could not identify any slaughter method for octopuses that was both humane and commercially viable on a large scale."
The company behind the proposed octopus farm, Nueva Pescanova, did not respond to a request for comment, but in a statement reported by the BBC this year, the firm said its welfare standards would ensure the animals were handled correctly.
"The slaughter, likewise, involves proper handling that avoids any pain or suffering to the animal," the statement added.
Prof Knight said octopuses bred for fast growth may have weakened immune systems to start with and that the stressful conditions of captivity could exacerbate this issue.
"If any pathogen gets into an environment like this, such as lice, it’s almost designed to enable outbreaks," he said, adding he expected disease could be a problem with intensively reared octopuses, too.
Rearing octopuses has not yet taken off on a large scale but there have been previous attempts. Kanaloa Octopus Farm opened in Hawaii in 2015, although whether it rears octopuses for consumption has been subject to dispute and US media reports indicate that the site, which has held open days, is closed to the public.
Rearing octopus larvae in captivity has proven difficult, although Japanese company Nissui announced in 2017 it had successfully completed the life cycle, which Nueva Pescanova said it also achieved two years later.
Lucrative market
Nueva Pescanova said it completed the life cycle "after decades of research at different centres and companies around the world".
"The company has allowed for the octopuses born in aquaculture to not only reach their adult age, but also to start reproducing in an environment outside of their natural habitat," a company statement said.
The firm aims to achieve annual production of about 3,000 tonnes of octopuses – said to equate to about one million – which compares to the approximately 420,000 tonnes caught in the wild each year for markets including Greece, Italy, Japan and Spain. The global market is worth $2.7 billion.
Nueva Pescanova previously stated its planned farm was "a response to the high international demand in the last few years", which had resulted in "a sustainability problem in the marine environment".
While cautioning that he could not comment on the conservation implications of octopus farming, Prof Francis Neat, a sustainability specialist at the World Maritime University in Sweden, said a widely held view was that aquaculture is "needed to take the pressure off the wild stocks".
However, he said it was largely an assumption that the rearing of marine animals helped to protect wild populations, rather than being supported by "hard proof".
According to Prof Jennifer Jacquet, of the Department of Environmental Science and Policy at Miami University, the idea that farming octopuses would relieve pressure on wild populations "is absurd".
"There’s no good evidence that’s happened for aquaculture generally," she said. "It’s allowed people to eat more seafood. It’s been additive, it’s not that it’s been a substitute."
Call for farming ban
Aquaculture can have local environmental impacts, Prof Neat said, such as through pollution or eutrophication, which involves nutrient levels rising to levels that harm the ecosystem.
Concerns have also been expressed about the level of fishing of wild populations to support the rearing in aquaculture systems of carnivorous marine organisms, of which octopuses are an example.
Nueva Pescanova has said water entering or leaving its farm would be filtered so it had "no impact on the environment".
As debate over the proposals continues, campaign groups such as Compassion in World Farming and Eurogroup for Animals are keen for the European Union to introduce a ban on octopus farming.
While the welfare issues that other farmed animals face are equally concerning, according to Prof Jacquet currently "we’re not locked into any system" and there is the opportunity to prevent these animals from having to face what she described as "a barren, lacklustre existence" on a farm.
She said the richness of the daily life of octopuses in the wild was "very hard to square with the argument we should be subjecting these animals to mass production".
"Right now we’re at a crossroads," she said. "We have a choice to prevent this from happening … it’s slated to be the next animal destined to a life of mass production.
"That represents something very powerful in the 21st century about where we are and what we want our relationship with these animals to be."
