The first inventory documenting the names and dimensions of more than 6,000 lakes and ponds in the Pyrenees is published

Some lakes in the Pyrenees have changed their names over the course of history, others are more than 100 metres deep, and many small ponds dry up in summer but host organisms capable of surviving until the water returns. The first inventory highlighting the richness of these aquatic ecosystems has now been published, bringing together information on 6,361 lakes and ponds across the mountain range, including those in Spain, Catalonia, Andorra and France. The catalogue, called LacusPyr and published in the scientific journal Geoscience Data Journal, includes data such as the surface area, depth and catchment basin of each body of water, as well as its official names, variants and historical names. It also assigns each one its own georeferenced identifier or ‘ID’ to facilitate identification and scientific research across different countries.

The creation of the inventory and its publication in the scientific journal was led by CREAF, in collaboration with the CSIC, the Centre for Advanced Studies of Blanes (CEAB-CSIC), the University of Barcelona (UB) and the Autonomous University of Barcelona (UAB).

Regarding toponymy, the researcher explains that names can change due to cartographic errors, differences in pronunciation or spelling, or because one name has become established at the expense of another. “In the catalogue, we have included the official name currently in use, but also the different variations.”

A particularly illustrative case is that of the Plan and Cabidornats lakes, located in the Aran Valley, in the Colomèrs cirque, within the surroundings of Aigüestortes i Estany de Sant Maurici National Park. Their names have been swapped in official maps over recent decades, and the names used in mountain guides do not always match those subsequently established in official cartography. This confusion has also extended to scientific literature, with some studies using names that, following subsequent toponymic changes, no longer correspond to the current cartographic names. 

There are also examples of linguistic and phonetic variations, such as the forms Redondo, Redó and Redon. “There is a historical explanation here. For example, Redondo appeared on some maps during the Franco era, Redó on some Catalan maps, and the current official name in Aranese is Redon, phonetically [reˈðuŋ],” Catalan explains.

Regarding the terms used to refer to these bodies of water, the publication also identifies geographical variations in generic terminology: in Catalan, ‘estany’; in Aranese, ‘estanh’ or ‘lac’, particularly for larger lakes. In Aragon, the term ‘ibón’ is commonly used to refer to high-mountain lakes.

The smallest ponds included in the inventory may have a surface area of just two square metres and, in many cases, do not even have their own name. Many are temporary and dry up during the summer, meaning that only species adapted to these intermittent conditions can live in them.

Among the most surprising are anostracans, crustaceans that are quite striking in appearance, with a somewhat alien-like look. They can display reddish or bluish colours and form very large populations. To survive when the water disappears, they produce resistant eggs that can remain in the sediment for a long time until conditions become favourable again.

“These temporary ecosystems and the organisms that inhabit them have still been little studied. In the new catalogue, we have also assigned a code to each of these ponds to identify them. This is a first step towards gaining a better understanding of habitats that are small and often barely visible, but of great ecological interest,” explains Catalan.

The inventory makes it possible to compare the size and depth of lakes in the Pyrenees. For example, Certascan, with a surface area of more than 60 hectares, is one of the largest lakes on the Spanish side of the Pyrenees and the largest in Catalonia. Cregüeña, located in the Maladeta massif, is one of the deepest lakes in the Pyrenees, with a depth of more than 100 metres. The latter, together with Lac Redon, is one of the deep lakes that have not been modified for hydroelectric power generation and are therefore of great conservation interest.

Lac Redon is also well known for being one of the most extensively studied high-mountain lakes in the world, with approximately 105 scientific papers published on it. In fact, Jordi Catalan and Marisol Felip have been researching the lake for more than four decades and are authors of many of these publications. They also study other lakes in the Aigüestortes area, such as Llebreta and Cabidornats (Plan).

According to the researchers, “maintaining this research over time is extremely valuable for building long-term datasets and studying how lake ecosystems respond to environmental and climate change, as well as understanding the impact of human activity throughout history,” they conclude.

In this study has also participated CREAF's researcher Meritxell Batalla. 

Reference article: Catalan, J., M. Batalla, T. Buchaca, et al. 2026. “LacusPyr, a Catalog of Lakes and Ponds of the Pyrenees.” Geoscience Data Journal 13, no. 4: e70109. https://doi.org/10.1002/gdj3.70109