RÉGIME ALIMENTAIRE ET STRATÉGIE TROPHIQUE SAISONNIÈRE DE LA LOUTRE D’EUROPE, LUTRA LUTRA, DANS LE MOYEN ATLAS (MAROC)

To learn more about the adaptability and predation behaviour of the European Otter (Lutra lutra) in semi-arid regions, its diet has been studied in Wadi Beth, a typical river of Middle Atlas (Morocco), from its source areas (Azrou) to El Kansera hill reservoir dam. Fecal samples (spraints) were systematically collected from six locations during two annual cycles, a collection per season campaign. The study reveals that the otter’s diet is classic (dominant fish), very typical and characteristic of aquatic ecosystems in arid Mediterranean climate, which is reflected in particular by the singular presence of prey like reptiles. Prey species richness totals more than 18 species. Moreover, the frequency of occurrence and relative abundance of taxa consumed were calculated from 2444 identified prey. Fish represent more than 75 % of the prey (relative abundance) with a very large predominance of 3 species of barbels. The anuran amphibians constitute 15 % of the prey. The rest is accounted for, according their respective importance, by insects, ophidians, a chelonian (Mauremys leprosa), birds, crustaceans and finally small mammals. Over time, the diet changed: in autumn 2010, cichlids, introduced into the river, appeared in the prey consumed. The proportion of prey types abruptly changed: perciforms, rare in spring and summer 2010 (less than 4 % of the prey) increased sevenfold in autumn 2010 (27 %) and then declined in the spring and more in summer 2011. In summer 2011, the proportion of barbels dropped, drastically offset by salmonids and, even more, by amphibians. In summer, the proportion of amphibians and ophidians becomes more important. Site variations are linked to local conditions: presence of ponds, nature of the bottom, slope, speed and flow of the water, etc. Finally, small-sized fish (salmonids and barbels) dominate the diet: 80 % are less than 10 cm.