The otter rejuvenates and repopulates our rivers

 

This may interest you: ‘Endangered Species in the Mar Menor’

As environmental conditions improve on the banks of our rivers, otters are increasingly appearing. In the 70s and 80s This mammal, an excellent swimmer, was in serious danger due to human actions. and lived in a very anxious situation. “Biologists at that time realized that the otter was in a very difficult situation. There was no danger of extinction, because in the west and northwest of Spain there were areas where the otter remained, but in many areas it disappeared, ”he recalls. Santiago Palason, Coordinator of the Nutria Group of the Spanish Society for the Conservation and Study of Mammals (SECEM)

“It has not completely disappeared in the eastern half of Spain, but it has disappeared. it disappeared in a large amount of water resources in the eastern and southeastern half, as well as around the big cities, ”says Yolanda Cortes, Expert of WWF Spain Program on Protected Species.

In those years, this animal also caused damage to other countries in our European environment. Miguel Clavero, Doñana Biological Station Researcher (CSIC), points out that “there was a general collapse that disappeared very quickly and on a massive scale in many parts of Central Europe.”

AUTHOR: Anthony Batet. Nutria SECEM Group

Why was the otter so threatened?

Experts agree that, among other factors, “Environmental pollutants” with high toxicity. such as PCBs, used in industry and banned in 1986, and DDT, compounds that were present in most pesticides and were used in agricultural activities.

Miguel Clavero points out “the effects of various pollutants that have impacted water systems since the 1950s. They threw a lot into the water, and the otters were badly hurt. ”

It was a sum of factors. River pollution and destruction of coastal ecosystems put the otter on ropes… Their survival rate was further compounded by the decline in prey and the isolation of many of their populations.

AUTHOR: Anthony Batet. Nutria SECEM Group

IN direct pursuit of a person on otters is another reason which explains its decline in those years. In 1953, the Council for the Extermination of Harmful Animals (known as the “Council for Parasites”) was established in Spain, which killed hundreds of thousands of wolves, lynxes, vultures and otters., inter alia, with the promotion and funding of public administration. “Like almost all predators, otters they were considered parasites… People were paid money to kill them because they competed directly with human interests. During this persecution everything was worth it, ”condemns Yolanda Cortez.

“Until he was protected, otter caught, killed and eaten”, Adds Santiago Palason. The killing of parasites continued until 1968.

IN commercial use of your skin, highly regarded for its insulating properties, still a threat to the species in some parts of the world… “There is still an active trade in otter skins in Russia and North America,” adds Clavero.

AUTHOR: Anthony Batet. Nutria SECEM Group

Keys to your current recovery

In Spain, otter restoration is carried out in parallel with implantation animal protection and environmental improvement standards for natural river habitats… “In the 1980s and 1990s, numerous wastewater treatment plants were put into operation in Spanish rivers, significantly improving water quality and eliminating most of the dangerous pollutants for otters that existed before,” says Santiago Palason. Another key lies in the greater abundance of food for the otter, which “It feeds on fish, if there is fish, and if not, then American crab, which has grown a lot in recent years.“, He adds.

The otter is a marten and a predatory mammal that leads a semi-aquatic lifestyle and draws all its food from the water. So, all interviewed experts agree on the main reasons for his recovery. that the otter is no longer pursued, that the health of the water has improved, and the ecosystems of the rivers.

AUTHOR: Anthony Batet. Nutria SECEM Group

The SECEM’s periodic censuses show how, during these four decades, the otter has been recovering throughout the peninsula., settling in areas where their community has disappeared or significantly decreased.

IN The following table, which includes data from the fourth census to be published by SECEM, shows how positive the evolution of the otter is. in a very generalized way in many autonomous communities. The table shows a marked increase in the percentage of otters present in each census in each region over the last.

Source: SECEM

This research is based on more than 8000 trace points carried out all over Spain with the help 1090 employees and shows that en more than 65% of samples detected the presence of otters

The evolution, demonstrated by four censuses conducted by the SECEM since the 1980s, highlights the apparent recovery of the otter. Coordinator of Nutria Group at SECEM, Santiago Palason stresses that this species “has recovered in the Basque Country., where there was a time when the otter was not, and now it is becoming more and more. ” It also emphasizes that “he is rebuilding areas of the Mediterranean. In Murcia and the Spanish LevantThe otter is recovering, but very slowly. ”

Miguel Clavero, a researcher at the Doñana Biological Station (CSIC), supports the same thesis: “The Levante area is the last area to be colonized, the outskirts of large cities are the most powerful place of its disappearance. Otter relocates land to Alicantealthough there is room for the otter to take up more territory. ”

Yolanda Cortez, an expert at WWF’s Spanish Species Protection Program, adds that “The otter now has more opportunities to colonize its habitat. that, in principle, they do not seem suitable for her, like the surroundings of big cities and life in rivers, which during periods of the year can completely dry up or have very little water. ”

Last May Francisco José García, a biologist on the Complutense University observer team, was able to locate and photograph a male otter on the banks of the Manzanares River in central Madrid., next to the old Vicente Calderón stadium, as part of the Madrid City Council’s biodiversity monitoring project.

AUTHOR: The otter was spotted by biologist Francisco J. Garcia in the Manzanares River, at the height of Puente de los Frances, in the vicinity of the old Vicente Calderón stadium.

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