When catfish are on pigeon-diet…

The talk “Non-Native freshwater fishes and their ecological impacts across ecosytems” by Julien Cucherousset from the Laboratoiore Evolution et Diversité Biologique, Université Paul Sabatier / CNRS, Toulouse (France) on April 17, 2013 was probably the most fascinating presentation at the International Conference on Biodiversity in Berlin. Julien and his group do research in the Garronne River basin (not only) with European Catfish (Silurus glanis), their ecology as species non-native to France and the  curiuos but often observed grouping behaviour in rivers and also discovered some very special indidiviuals:

From a bridge at the river Tarn (southern France), they observed a group of European Catfish (Silurus glanis) trying to go on land (beach) to get and catch thirsty pigeons that stay on the gravel bar right at the edge to the water surface to drink river water. This was not a single time, rather it seems that the fish adapted to their local environment and changed their feeding pattern. The research group observed that behaviuour for some time and documented it with videos that are wide spread now in the internet. Additionally they also analysed the data they gathered in the field scientifically and calculated e.g. a rate of successful beaching attacks (if I can remember correctly it was 28%?). They also conducted stable isotope analysis for getting deeper insights into the food web relations of these non-native fish species and found that some individuals  feed to a considerable amount on these pigeons. A really interesting and compelling talk, especially accentuated by videos like this:

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