The coypus are already stealing the spotlight in the Onyar tents and threatening Barcelona.

GironaThe coypu on display from the Onyar River near Girona create a great deal of excitement among passersby crossing the city's bridges. They are in greater demand than the classic carp, which has also been cornered by the Ebro thornback, another much more abundant foreign species that can reach comparable sizes. The coypu have found in the lower reaches of the river that runs through Girona, with its calm waters, rich vegetation, and naturalized banks, a perfect ecosystem for reproducing and forming families. They can be seen on the riverbanks or swimming in the water, and they do not flee at the presence of humans.

The coypu is an animal of South American origin that arrived in Catalonia from France about 25 years ago. It can weigh up to 7 kilos and has been bred in Europe since the 1920s for its fur. Its proliferation in the wild comes from specimens that escaped from farms. It is present in the Alt and Baix Empordà regions, in Gironès, in the Pla de l'Estany region, and is about to enter the Osona region. Specimens have also been seen in the lakes of Sils, from where, sooner or later, it will spread to the Besòs and Llobregat basins, thus entering the Barcelona metropolitan area. Biologist Quim Pou, from the La Sorellona association, a specialist in continental aquatic fauna and ecosystems, warns that this invasion can be temporarily halted or delayed, but is convinced that "it is inevitable that over time it will end up spreading throughout the rest of the country." Pou asserts that the rat-like appearance of this animal often creates repulsion in people, although normally "animals with fur inspire sympathy, whether or not they are invasive species."

A line in the rice fields

The coypu has been causing problems for rice farmers in the Baix Ter region for years, which is why they are trying to "keep it at bay," explains Josep Pericay, president of the Plant Protection Association of Empordà rice producers. The response to this agricultural pest involves installing traps to capture as many individuals as possible, a task handled by the Catalan Forestry Agency, an entity dependent on the Generalitat de Catalunya (Catalan Government). "This year the coypu have not caused any major damage, only minor damage to the edges of fields, near irrigation ditches, or runoff areas; however, we are very clear that, if it were not controlled, it would explode," explains Pericay. This year they expect a larger rice harvest than last year, although temperatures should remain stable, without sharp fluctuations, to facilitate optimal ripening.

Coypu control efforts are also being carried out in Lake Banyoles, where they are ravaging the riparian ecosystems. For now, as in Baix Ter, they are being kept at bay through trapping.

Quim Pou explains that last year his organization managed to eliminate around 200 coypu specimens in the Gironès region. They continue working on two projects, although they have fewer resources. This year they have removed less than half. "Eradicating it is unthinkable, because it is a very prolific species," he warns.

Disproportionate costs

The Department of Territory and Sustainability of the Generalitat (Catalan Government)'s management plan for the containment and control of the coypu recognizes that eradicating the species in Catalonia "is technically feasible but entails disproportionate costs (required personnel and materials) in relation to the potential benefits obtained." The priority is to limit expansion in the southern basins of the Ter and Tordera rivers and the headwaters of the Muga and Fluvià rivers to the north. Control priorities are to reduce population density and eliminate damage to sensitive habitats and crops. It is estimated that around 2,000 coypu specimens have been eliminated in the Girona region in recent years.

Ponç Feliu, biologist, environmentalist, and director of the Cap de Creus Natural Park and the Empordà Wetlands, recalls that he first saw this animal in the Camargue in the 1980s, and that it was already a common species in the wetlands of southern France. Now that it's also a common animal here, he's seen the latest specimens in remote locations around Cap de Creus, such as the Pení area, an area with very little water, which reflects its ability to move and conquer territory. Feliu admits that it's an animal that may amuse people somewhat, but it ends up causing significant damage to the wetland ponds, habitats for many birds, and to the rice paddies and lagoons, which lose water through the tunnels they excavate. A coypu can have up to ten pups a year. "Since it has no predators, control measures must continue, as any invasive species occupies the niche of another and has an impact," he asserts. "The fight against the coypu must continue, even though we know that sometimes you've lost it from the start."

Otters in the Onyar

Although they are much more timid, but three times larger than coypus, otters are also found in the Onyar. A few pairs have been spotted after finding a stable habitat. In recent years, fleeting images have been captured, some even in the act of hunting a fish. The presence of these animals has always been considered a sign of biodiversity and good water quality. The animal that seems to be declining in the Onyar is the classic carp, the city's icon, which most people confuse with the Ebro thornback. However, the carp is still an exotic species, although it has been proliferating in our rivers for many years. Therefore, when an operation was carried out a couple of years ago to eliminate foreign species from the river, action was also taken against the carp.

Coypu pâté

Despite the alarm and rejection that the coypu usually causes, its meat, with a taste somewhere between rabbit and hare, is appreciated in some rural areas of France for making pâté (ragondin pasta). Taking advantage of the need to control the pest, which began in France before it did in Catalonia, they integrated it into the local cuisine. The preparation usually combines its lean meat with pork and aromatic spices. Although it is not a mass-consumed product, it has been integrated into traditional popular and game-based cuisine. It can be easily found in the Vendée department, in the Pays de la Loire region. Although hunting is one way to control it, not even in France has it been able to offset the spread of the coypu.

A more subtle invader

An animal much less visible than the coypu or the Ebro blackhead, but equally or more worrying, is the misgurno, an elongated fish about 25 centimeters long that resembles an eel and hides beneath the mud. It is a great predator with a great capacity for adaptation, also proliferating in the Onyar and Ter rivers. It is even capable of breathing air from the atmosphere to survive in stagnant waters lacking oxygen. It spread through aquariums and its use as live bait to catch other fish. It is now a threat to the rest of the native species, and its proliferation clouds the water and concentrates ammonia.

Two Egyptian geese

Another foreign animal that also made an impact on the Onyar River as it passes through Girona was the Egyptian goose. A pair settled there for a time. "Although it's a beautiful and exuberant animal, one day or another we'll have to act if the population expands," says Quim Pou.