In recent years, more fish farms have been built on the high seas, known as off shore.
Their proliferation in open waters, often several kilometers from the coast, has provoked heated debate: some see them as the next frontier for the sustainable production of fish such as Atlantic salmon, sea bass and tuna, while for others it is one more step in the creation of “industrial farms of the sea”.
What almost everyone agrees is that these farms in places further away from the coast are about to increase even more in the coming years. Between 1961 and 2017, global demand for fish grew by an average of 3.1% per year.
Some believe that offshore farms can relieve pressure on fish populations that are targeted. In 1974, according to the Food and Agriculture Organization of the United Nations, about 10% of the fish stocks in fisheries were being depleted too fast for the fish to be replaced by juveniles because too many broodstock had been caught. . In 2017, this proportion had risen to 34%.
Others argue that the environmental impact outweighs any potential benefits. Among these environmental risks they list the fact that the constant flow of water through farms allows food, antibiotics and fecal matter to enter open water to the risk that farmed fish could escape and threaten local ecosystems. .
There is also a risk that the success of farms may depend on processing small fish for use as farmed feed.
Fish and shellfish farms have been growing at a breakneck pace all over the world, particularly in China. According to the Food and Agriculture Organization of the United Nations, between 1990 and 2018, fish farming grew by 527%.
Fish farming in the high seas is among the riskiest bets in the sector; The cages must be built to withstand the open sea, waves well over a meter high and strong currents, while their remote locations mean that any problems often take longer and more expensive to fix.
Even so, tens of millions have been invested in the sector. Virginia-based Forever Oceans has raised nearly $120 million from investors, according to Bloomberg, while a venture fund linked to Walmart heiress Christy Walton has backed half a dozen offshore aquaculture-related initiatives. .
A 2019 study that collected water samples near submerged fish cages off the coast of Panama concluded that, when properly located, offshore farms can produce a relatively small pollution footprint. Another from 2011 that compared more than 15,000 bluefin tuna raised offshore and closer to shore found that those raised offshore had reduced mortality and were less prone to sea lice.
A paper published in Nature 2020, argued that the high costs associated with offshore farming meant these products would be inaccessible to low-income consumers, suggesting limited scope for alleviating food insecurity. The researchers also noted that the fuel consumed by ships heading to and from farms could compromise the environment.
In general, the evidence supporting offshore fish farms remains scant. Remote locations, he says, would make it impossible to sustainably regulate industrial fish farming in our oceans.
One option may be aquaculture in land tanks, where fish are raised in isolation from the surrounding ecosystem. This is done with salmon and turbot and some other species of fish and crustaceans.
There are projections that suggest that the demand for food could double by 2050 as the world population grows and becomes wealthier.
As companies experiment with fish feeds derived from products such as insect proteins or produced in bacteria to minimize pressure on wild-caught fish populations.
Will the same problems be repeated as the production of animals and plants on land? Or from the previous aquaculture facilities? depends to a large extent on the species cultivated, their densities and the waste they generate.
Offshore farms:
Farms on land: