- Intensive harvesting of the mollusk known as “loco” and salmon farming are damaging the seabed and reducing the biodiversity of the Guaitecas Archipelago, in northern Chilean Patagonia.
- To restore it, divers are transporting shellfish and rocks that serve as food and shelter for the loco and other commercially valuable species.
- The Pu Wapi Indigenous community is also working to enhance marine protection by requesting a Coastal Marine Area for Indigenous peoples.
Daniel Caniullán has been diving in the cold waters of the Guaitecas Archipelago in northern Patagonia, Chile, for more than 30 years.
“Just by looking at the seabed landscape, you can tell what species you are going to find,” he says. Just as it is possible to recognize the loss of a diverse forest on land, Caniullán’s experience underwater allows him to quickly identify damaged areas.
To undo the damage, local divers “repair or reorganize the seabed to restore biodiversity and interspecies relationships,” according to a recent paper published in the British Ecological Society.
“It is a very practical example to understand how knowledge passed down from generation to generation can be used to recover certain areas and face current challenges such as the devastation of the underwater substrate,” says Florencia Diestre, anthropologist and co-author of the paper, with the Austral University of Chile.
Caniullán is a lonko, the Mapudungún word for leader, of the Mapuche-Williche-Lafkenche Pu Wapi Indigenous community in the town of Melinka on Ascensión Island. This territory is a 15-hour boat ride from the nearest town and more than 1,000 kilometers (620 miles) away from Santiago city.
But distance was no obstacle in the 1980s when the “loco (Concholepas concholepas) [shellfish] fever” broke out, says Jaime Ojeda, co-author of the study and a marine biologist at Cabo de Hornos International Center at Chile’s University of Magallanes. Nor was it an obstacle to the arrival of the salmon industry, which brought new waves of damage, according to Caniullán.
Underwater deserts
The leader of Pu Wapi recalls that the Guaitecas seabed was once “rich in biodiversity.” After diving, sometimes to depths of 40 meters (131 feet), he would lift branches of large seaweed to discover octopuses, fish and crustaceans.
“There were countless species of high economic value, high quality and good size,” he says. Now, according to him, many of these underwater forests are turning into deserts.
The first impact was in the 1980s when fishermen from all over the country arrived to harvest “loco,” a mollusk highly prized in national and international cuisine. Loco is a sea snail of great commercial importance for communities in southern Chile, such as Pu Wapi.
It is also a carnivorous species, controlling the proliferation of other mollusks and bivalves. For this reason, intensive harvesting has altered the ecosystem. In 1989, measures were established to protect the species, including closures and quotas. Divers and artisanal fishermen were also required to operate under the Benthic Resource Management Areas registry, which grants them exclusive exploitation rights.
“But we are always invaded by fleets from other regions,” Caniullán says. There is little enforcement. For example, Caniullán says that maritime inspectors do not have boats, so they do their work “via email.”
Then in the 2000s, salmon farming companies arrived, bringing with them new impacts on marine biodiversity. They introduced salmon, a non-native species, for farming. Overpopulation of salmon in hatcheries and the use of antibiotics now pollute the Chilean Sea and trigger marine hypoxia, which is when oxygen levels in the water decrease significantly.
“Many fjords are dying due to low oxygen levels. There are areas not reached by the industry that are in better condition,” Caniullán says. He adds that the “picoroco” — or giant barnacle (Austromegabalanus psittacus) — “has died off by almost 90% as a result of chemicals from the salmon farms.” This crustacean is one of the main sources of food of the loco.
Divers rearrange the seabed
In an attempt to recover the landscape, divers in Ascensión have been relocating rocks, colonies of marine invertebrates called piures (Pyura chilensis) and other species of mollusks and barnacles to areas they want to revitalize for around 20 years. The piure is a tunicate “that generates a microecosystem, a founding species that harbors more life,” explains Ojeda.
The result has been increased local biodiversity. And by transferring piures, divers also ensure that locos have access to one of their favorite foods, so these animals do not have to travel to more distant areas for prey.
“When we see that the loco has little food, we leave plenty of food for them so that they stay in the area, recover their quality, and become healthier,” Caniullán says. In addition to piures, they leave Chilean mussels (Mytilus chilensis), too.
Ojeda says these actions complicate the seabed. In other words, what was once monotonous environments, like a grassy meadow, becomes more diverse.
“We call this reciprocal contributions,” says Ojeda.
Unlike the notion that nature provides services to humanity, this concept takes into account the actions and interactions between humans and nature that benefit both parties.
When divers search for their quarry, they target adult specimens rather than juveniles, which would affect the reproduction and survival of the species.
Diestre accompanied a trip to collect shellfish, during which the divers made several dives at different points, abandoning areas with few resources or animals that had not reached maturity. The anthropologist confirmed that “it wasn’t a matter of diving and taking whatever was found, but rather deciding what was optimal and what had to be protected.”
Divers avoid collecting in areas that need to recover.
“This is confidential work in freely accessible areas, because when others find out what we do, they take advantage of our work,” says Ojeda, referring to competition from divers who come from other regions.
Protecting seaweed
The divers of Pu Wapi also protect forests of floating kelp (Macrocystis Pyrifera), the largest seaweed on the planet. Kelp is harvested for the production of alginates, an ingredient used in medicine, the food industry, and other sectors. Chile banned harvesting kelp for 10 years in 2025.
Ojeda explains that in southern Chile, one of the first indicators that a marine habitat is recovering is the reappearance of these seaweed forests. At least 300 organisms live, feed and reproduce among the kelp branches, which can grow up to 70 m (230 ft) high.
For Caniullán, protecting these algae is key because sea urchins — another commercially important animal in southern Chile — feed on them.
Diestre says she believes that “it is necessary to recognize the value of this local and traditional knowledge in order to achieve sustainable practices.”
Such cases, she adds, allow us to understand the ocean as a cosmogonic relationship — our place on the planet and its origins — and not just as a resource. “It is a radical difference from some more biological disciplines,” she says.
The anthropologist says she hopes that the article published with her colleagues, which “was well received abroad,” will help recognize these conservation practices and show that both Indigenous and scientific perspectives have the common goal of preserving the ocean.
Another fight in Pu Wapi
Around 30 families live in Pu Wapi and most of them are connected to the sea. They are shore gatherers, shipbuilders and divers. “We dream of having a Marine Coastal Space for Indigenous Peoples (ECMPO),” says Caniullán. ECMPOs are a mechanism that allows Indigenous people to protect their traditional practices and manage areas to conserve ecosystems.
However, he says, after more than 10 years of paperwork, the Regional Commission for Coastal Use (CRUBC) in the Aysen region has denied two requests. During the process, the salmon industry “played the victim,” in the words of Caniullán, saying that if the government approved the management area, they would have to lay off their workers.
The tensest moment came in 2024, when Caniullán and his family were sailing to another island in the archipelago and a neighbor called to warn them that something strange was happening at their home. When the neighbor arrived with the police, he found the front door forced open, the diver’s room in disarray, and Caniullán’s passport destroyed.
The leader says that that same day he received a WhatsApp message demanding that he withdraw his application for the marine space. Although he filed a complaint, there have been no results from the investigation so far.
“The authorities said, ‘We are going to implement the Escazu Agreement,’” he recalls, but points out that this tool, which seeks to guarantee the safety of human rights and nature defenders, has no regulations for its implementation.
Despite the threats, Caniullán will continue with the ECMPO request because “it complied with everything the law says.” The community has taken the case back to the Supreme Court (they already did so after the first rejection), but this time they are determined to take it to the Inter-American Commission on Human Rights.
Caniullán says they are not against the salmon industry, but they are concerned about its impact. The inhabitants of Pu Wapi want this and other activities to be carried out “with prudence and balance.” The fight continues, he explains, because the inhabitants of this community, so far from the centers of decision-making, “owe everything to the wealth of the sea.”
Banner image: Daniel Caniullán diving in search of sea urchins. Image courtesy of Daniel Caniullán.
This story was first published here in Spanish on April 24, 2025.
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