La Loutre du Maroc. Répartition et alimentation

This book first takes stock of Eurasian otter. The second part of the book analyses the feeding strategy of Eurasian otter in Morocco. It is a substantial contribution since, if there exist many studies about this specific topic in Europe, little is The second part of the book analyses the feeding strategy of Eurasian otter in Morocco. It is a substantial contribution since, if there exist many studies about this specific topic in Europe, little is known about otters’ diet at the Southern limits of its biogeographical range, namely in the Maghreb. From a methodological point of view, we collected data by gathering spraints before analysing them in the lab to identify prey. We then estimate the relative abundance of consumed taxa. We weight this relative abundance based on the weight and size of prey, relying on the correlation between the length of the cephalic parts extracted from spraints and the length and weight of reference fish collected in rivers. In the main collection area, the oued Beht (770 spraints), otters display an opportunistic feeding behaviour, with large variations in relative abundance of barbels in their diet. A huge drop in their consumption around the 2011 summer drives this variation, a drop probably due to the decline of barbels during this period, something in line with reports by many fishermen in the area and by control catches we perform using fishing gears (“nasses”). Otters do compensate the reduced availability of barbels by eating more cichlids. Outside of the oued Beht, we collected and processed 229 spraints in the river basins of the Oum-er-Rbia, Haut-Atlas (Tensift), Dades/Draâ, Ziz, Guir, Moulouya and Rif wadis. On the basis of the whole dataset, we do confirm the opportunistic behaviour of Eurasian otter in Morocoo, whether it is because of the diversity of consumed prey in terms of size or of species known about otters’ diet at the Southern limits of its biogeographical range, namely in the Maghreb. From a methodological point of view, we collected data by gathering spraints before analysing them in the lab to identify prey. We then estimate the relative abundance of consumed taxa. We weight this relative abundance based on the weight and size of prey, relying on the correlation between the length of the cephalic parts extracted from spraints and the length and weight of reference fish collected in rivers. In the main collection area, the oued Beht (770 spraints), otters display an opportunistic feeding behaviour, with large variations in relative abundance of barbels in their diet. A huge drop in their consumption around the 2011 summer drives this variation, a drop probably due to the decline of barbels during this period, something in line with reports by many fishermen in the area and by control catches we perform using fishing gears (“nasses”). Otters do compensate the reduced availability of barbels by eating more cichlids. Outside of the oued Beht, we collected and processed 229 spraints in the river basins of the Oum-er-Rbia, Haut-Atlas (Tensift), Dades/Draâ, Ziz, Guir, Moulouya and Rif wadis. On the basis of the whole dataset, we do confirm the opportunistic behaviour of Eurasian otter in Morocoo, whether it is because of the diversity of consumed prey in terms of size or of species) geographic distribution over the whole of Morocco in the early 2010’s. This work reflects on the review work done in 1988 at the Morocco level (Mac Donald & Mason, 1984 ; Broyer et al. 1988 ), and in 2012, on a smaller part of the country (Delibès et al., 2012). We report on the current situation of this species in the country as many significant changes take place in the aquatic environment in Morocco, mostly in the plains (varying water regime, canalization of rivers, water pollution, etc.). The data collection methodology relies on extensive surveying of all Moroccan wadis on a biyearly basis (in autumn and at the end of the winter season). We did search for any pieces of evidence of Eurasian otter presence (footprints, spraints, meal remains). We carried on field missions from 2009 to 2012, with some additional visits in 2015 and 2017. A comparison of the former (1980) and current distribution of the otter shows little change, except in the South of Agadir where we could find some evidence of the animal presence, in spite of objectively more degraded living conditions for Eurasian otter, threatening the species survival. In the medium run, one of the main threats on otter population comes from the extended drying up of some river stretches, sometimes over several tens of kilometres. This will eventually lead to the isolation and segmentation of sub-populations, mostly in mountainous regions. The second part of the book analyses the feeding strategy of Eurasian otter in Morocco. It is a substantial contribution since, if there exist many studies about this specific topic in Europe, little is known about otters’ diet at the Southern limits of its biogeographical range, namely in the Maghreb. From a methodological point of view, we collected data by gathering spraints before analysing them in the lab to identify prey. We then estimate the relative abundance of consumed taxa. We weight this relative abundance based on the weight and size of prey, relying on the correlation between the length of the cephalic parts extracted from spraints and the length and weight of reference fish collected in rivers. In the main collection area, the oued Beht (770 spraints), otters display an opportunistic feeding behaviour, with large variations in relative abundance of barbels in their diet. A huge drop in their consumption around the 2011 summer drives this variation, a drop probably due to the decline of barbels during this period, something in line with reports by many fishermen in the area and by control catches we perform using fishing gears (“nasses”). Otters do compensate the reduced availability of barbels by eating more cichlids. Outside of the oued Beht, we collected and processed 229 spraints in the river basins of the Oum-er-Rbia, Haut-Atlas (Tensift), Dades/Draâ, Ziz, Guir, Moulouya and Rif wadis. On the basis of the whole dataset, we do confirm the opportunistic behaviour of Eurasian otter in Morocoo, whether it is because of the diversity of consumed prey in terms of size or of species.