The LIFE RESQUE ALPYR project, coordinated by the CEAB-CSIC, begins a pioneering pilot test to eliminate invasive fish with a biodegradable biocide in a high mountain lake. This initiative is part of a broader strategy to restore aquatic habitats, with the aim of turning restored lakes into biodiversity reservoirs and ecological corridors. It will be the first application in a lake in southern Europe.
One of the main threats to high mountain ponds is the presence of introduced fish species, such as trout or especially verón, which destroy native species and seriously alter the balance of these ecosystems. For this reason, one of the key actions of the LIFE project is the restoration of 22 high mountain lakes in the Pyrenees and the Alps by eliminating fish introduced by man.
Rotenone: an innovative solution
Until now, removal of introduced fish has been carried out with conventional capture techniques such as nets, traps and electrofishing. But in the case of the verón (due to its small size and high reproductive rate), these methodologies are very complicated to apply. Alternative methods had to be explored.
The chosen method is to eliminate it with a product called “rotenone.” It is a natural biodegradable ichthyocide extracted from the roots of plants of the Fabaceae family, traditionally used for fishing in Southeast Asia and South America. In the environment, rotenone degrades rapidly, persisting for only a few days or weeks.
Until now, its use as an ichthyocide has been concentrated in North America, Australia, New Zealand, the United Kingdom and Northern Europe, especially Norway, with some specific experiences in the rest of Europe.
Pioneering application in the high mountain ponds of the Pyrenees
In the Pyrenees the use of rotenone is pioneering. The experiment should provide crucial data on the effectiveness of this substance in a new biogeographic context.
The pilot test is carried out in a pond located in the peripheral area of the Aigüestortes and Estany de Sant Maurici National Park, in the Vall d’Aran. A body of water located in a strategic location has been chosen, since there are no ponds or large water courses upstream that could represent a risk of fish reappearance once the intervention is completed, nor that would make it difficult to apply the product without affecting the no other habitat nearby.
The action is carried out by Sorelló, Estudis al Medi Acuàtic, S.L. and the LSorrellona Association, with the coordination and scientific supervision of the Centre for Advanced Studies of Blanes (CEAB, CSIC) and the Institute of Environmental Diagnosis and Water Studies (IDAEA, CSIC), with the direct support of the Conselh Generau d’Aran, Forestal Catalana, and Aigüestortes and Estany de Sant Maurici National Park (PNAESM).
