One of the main threats to these ecosystems is the presence of introduced fish species, such as trout and, especially, the common minnow, which outcompete native species and severely disrupt the balance of ecosystems. Therefore, one of the key actions of the project is the restoration of 22 high mountain lakes in the Pyrenees and the Alps by eliminating introduced fish using traditional techniques.

Rotenone: An innovative solution

Conventional fish capture techniques, such as nets, traps, and electrofishing, are commonly used for fish removal in mountain lakes. However, biological and environmental constraints, such as the size of the lake or the presence of minnows, can limit their effectiveness. For this reason, exploring alternative methods is necessary.

The common minnow, a small cyprinid with rapid growth, high reproductive rate, and great adaptability, can form dense populations even in extreme conditions, making population control challenging. In this context, a pilot test has been conducted using rotenone, a natural biodegradable ichthyocide extracted from the roots of plants in the Fabaceae family, traditionally used for fishing in Southeast Asia and South America. It is similar to troca or Verbascum, a plant historically used for fishing in ponds and streams in the Pyrenees, though now its use is prohibited.

In the environment, rotenone degrades quickly, persisting only a few days or weeks. So far, its use as an ichthyocide has been concentrated in North America, Australia, New Zealand, the United Kingdom, and northern Europe, particularly in Norway, with some isolated experiences in other parts of Europe, including Spain.

Pioneering application in high mountain lakes of the Pyrenees

The pilot test was carried out in a lake located in the peripheral area of the Aigüestortes and Estany de Sant Maurici National Park (PNAESM), in the Aran Valley. A strategically located body of water was chosen, as there are no lakes or large upstream watercourses that could pose a risk of fish reintroduction after the intervention, nor that would hinder the application of the product without affecting nearby habitats.

The experiment will provide crucial data on the effectiveness of this substance in a new biogeographic context. The entire process will be monitored through a rigorous follow-up program, ensuring the safety and efficacy of this innovative technique.

The operation was carried out by Sorelló, Estudis al Medi Aquàtic, S.L. and the LSorellona 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 Aran Council, Forestal Catalana, and the Aigüestortes and Estany de Sant Maurici National Park (PNAESM).

LIFE RESQUE ALPYR

This is a LIFE project aimed at the recovery of mountain aquatic habitats by improving the conservation of various habitats and species in four Natura 2000 sites in the Alpine biogeographic regions of the Pyrenees (northeast Spain) and the Alps (northwest Italy) (www.liferesquealpyr.es).

The project is co-financed by the European Union’s LIFE 2020 program, which promotes conservation and habitat and species restoration actions in protected areas within the European Natura 2000 network. In the Catalan part of the project, participants include the Department of Territory, Housing, and Ecological Transition of the Generalitat de Catalunya, the Conselh Generau d’Aran, the University of Barcelona, the IDAEA-CSIC, the companies Forestal Catalana and Sorelló Estudis al Medi Aquàtic, and the La Sorellona association. On the Italian side, partners include the Mont Avic Nature Park, the Università degli Studi di Pavia, the Università della Calabria, and the Water Research Institute of the National Research Council (IRSA-CNR). Additionally, the Andrena Foundation, the Gran Paradiso National Park, and the municipalities of Espot and Lladorre are participating as co-financiers.

The meeting was organized by the CBN of the Pyrenees and Midi-Pyrénées as the secretary of the scientific interest group (GIS) “Lacs des Pyrénées” and brought together researchers, managing entities, and decision-makers committed to the conservation of high mountain lake biodiversity.

The LIFE RESQUE ALPYR project presented as a inspiring project

The first day was dedicated to sharing knowledge, exchanging ideas, and strengthening collaboration in favor of preserving mountain lakes through interactive sessions, workshops, and presentations of inspiring projects.

Dr. Marc Ventura, coordinator of the LIFE RESQUE ALPYR project and researcher at the Center for Advanced Studies of Blanes (CEAB-CSIC), was one of the main figures of the day. The first presentation focused on the biodiversity and conservation of high mountain lakes in the Pyrenees and the Alps, highlighting the natural heritage represented by these ecosystems and the threats they face (presence of invasive fish and effects of global change).

He then presented, among other things, the objectives and conservation actions of the LIFE RESQUE ALPYR project and the expected outcomes of fish eradication in the lakes.

Tribute to Dr. Didier Galop

The second presentation was a tribute to the recently deceased Dr. Didier Galop, a renowned geographer, paleolimnologist, and director for more than 10 years of the Man-Environment Observatory (OHM) of the National Center for Scientific Research in France (CNRS) and the GEODE Research Laboratory.

Marc Ventura narrated and detailed the history of fish introductions in high mountain lakes. A story studied alongside Didier Galop and Olivier Baudier.

In the Pyrenees, fish introductions were carried out historically for self-consumption and trade, using native trout from nearby rivers, always in a few lakes. In the lakes of the Alps, there are also a few introductions dating back to the medieval period. However, in both the Alps and the Pyrenees, it was from the second half of the 20th century that fish introduction became widespread with the advent of recreational fishing.

Currently, 32% of the lakes in the SCI Pallars and 75% of the SCI Aigüestortes have stable fish populations. In the Italian Alps, introduced fish are present in 89% of the lakes in the Mont Avic Natural Park and 35% of those in the Gran Paradiso National Park.

A cross-border project for high-altitude lakes

The ultimate goal of these meetings is to build an ambitious and cross-border program for the Pyrenees by 2026 through a strategic partnership .Collaboration between managers, researchers, and entities will be essential to address the biodiversity conservation challenges of the coming years in the Pyrenees.

Lucia presented the effects of introduced fish on insectivore shrews, one of the topics of her PhD project titled “Cascading ecological effects of alien fish introduction and removal in high mountain lakes” (financed by the LIFE RESQUE ALPYR).

PhD Day at the University of Calabria

PhD Day at the University of Calabria was a day entirely dedicated to the University’s doctoral students who presented the research activities carried out, with the aim of raising awareness of the scientific value of the doctoral path and making people reflect on the benefits generated in society.

At the end of the day, the PhD Competition, an exciting “competition” divided into two sections: the Poster Competition in which the competitors illustrated the posters created specifically for their research topic, and the Pitch Competition, a presentation of a few minutes focused on the studies conducted. Rita Megale, a PhD student in Physical, Chemical, and Materials Sciences and Technologies, won the Pitch Competition. The Poster Competition for the Technical-Scientific Area was won by Lucia Bello, a PhD student in Life Science and Technology, while for the Socio-Economic and Humanistic Area, Aurelia Zucaro, a PhD student in Politics, Culture, and Development, was awarded.

The morning was opened by greetings from the Rector Nicola Leone, who underlined the increasingly important importance that research doctorates will assume in the training of the future ruling class.

You can find the prize-giving session of the day here.

Introduced fish represent the most important threat for high mountain lakes but angling in mountain lakes is a popular recreational activity. Reconciling this potentially conflictive framework probably represent the most challenging communication objective of the whole project.

The aim of the rod-angling sessions is to involve local recreational anglers in an attractive and engaging way, presenting them the scientific and conservation values of the project, and inviting them to participate in the eradication actions. Previous experiences have demonstrated that beside the educational aspects, the participation of the rod-anglers has also an important impact on the first phases of the eradication process, contributing significantly to the elimination of the adult trout population.

Thanks to the special fishing permits released by the National Park to 15 anglers from the Cogne Valley, we were able to remove 467 brook trout in two days.