Scientists battle to save critically endangered Argentinian otter with only 250 of the species left


Scientists in Patagonia are working hard to save a critically endangered otter from extinction after its population was decimated by the leather industry and now there are only 250 of them left.

The Southern river otter was nearly hunted to extinction because of demand for the fur industry in the 1950s and despite this practice being banned years ago, its marine population is still critically endangered in its natural habitat in Patagonia, in southern Argentina, where there are only 200 individuals left in the freshwaters of the Nahuel Huapi National park and only 50 on the marine coast of Tierra del Fuego.

Human activity, habitat degradation, wild dogs, and exotic American minks are direct threats to the survival of this species, which plays a key role in the ecosystem, because locally it is an apex predator and it therefore helps to regulate the numbers in other species.

Dr Alejandro Valenzuela is a biologist and researcher at CONICET (the National Scientific and Technical Research Council), as well as a professor at the National University of Tierra de Fuego. He is coordinating efforts to protect the Southern river otter and said that the southern river otter (Lontra provocax) ‘has the most restricted distribution in the world, with only two populations’.

He explained how human activity poses a direct threat to the species, saying: ‘It is believed that they are being killed by fish farmers because they kill the fish.’

He also said that chemical pollution and noise pollution, notably from boat engines ferrying tourists around and fishing boats, are also affecting the species as ‘these animals do not react well to the presence of humans’.

Speaking about exotic American minks, Dr Valenzuela explained: ‘They are competing for food and live in the same habitat as the Southern rive rotter, and furthermore we are concerned that they could pass on diseases.’

Scientists are deeply concerned about this situation and an expedition called La Delgada Linea Azul (The Thin Blue Line), conducted by the Huillin Tierra de Fuego Project in cooperation with the Rewilding Argentina foundation, was launched to find out more about the presence of this species in Tierra del Fuego, and especially in the Mitre Peninsula. The location had never been explored before in search of this species despite the project running for over 15 years, and this is because it is so difficult to go there.

This part of the Patagonia is very important, as it is believed to be a kind of biological corridor between the individuals living in the National Park of Tierra del Fuego and those in the nature reserve on the island of Isla de los Estados, which allows both populations of the species to avoid isolation and this in turn leads to them having better genetic material.

The experts have now assessed the Mitre Peninsula and collected faecal samples to find out more about its diet. They also want the authorities to declare the Mitre Peninsula a protected area and set up clear rules to protect the endangered otters.

Dr Valenzuela explained that the Southern river otter is at the top of the food chain because it is an apex predator in the area and it “maintains a numerical balance when it comes to the numerous prey it hunts in its natural habitat.”

Dr Valenzuela drew a direct comparison with the disappearance of California’s otters years ago and how this resulted in a dramatic increase in the numbers of hedgehogs in the American state. This in turn led to them eating a disproportionate quantity of plant life and ‘when they had eaten all the food, the hedgehogs died out.’

He explained that another key role they play is removing ‘nutrients from the sea and giving them back to the forest’, connecting the algae forests in the ocean to forests on land.

The experts hope that the faecal samples they collected during the expedition will also help them learn more about the diseases and the parasites species may face, as well as about their diet.

While on the first day of the expedition they did not find any signs of life, over the course of the following days they detected the presence of the endangered otters in an area they had not been seen in before.

They have set up automatic cameras in locations where there was evidence of this animal’s presence to monitor their lifestyle and activity, as well as their interactions with other species.

Dr Valenzuela explained that these animals are very evasive and avoid human contact. They are typically solitary as sooner the female has given birth to a litter of pups. He said: “The males leave their territory in search of females, and after they have mated, the females reject them and they are the ones who take care of the offspring.”

The expert also said that the species is also present in Chile where there are about 500 individuals in freshwaters, meaning there are only 700 freshwater Southern river otters known to be left in the wild, while the Chilean population that lives by the sea is currently unknown, having last been studied in the 1980s.

He said that salmon farming in particular poses a threat to the species and to the rest of the ecosystem because it pollutes a lot. This is not only due to the waste material the fish farms produce, but also because of the amount of antibiotics used.

The experts say that if Tierra del Fuego is not declared a fully protected area for this species, this could lead to the extinction of its marine population in Argentina.