Additional and unusual captures of elasmobranch species from the northern coast of Tunisia (central Mediterranean)

Abstract

The present paper reports occurrences of six elasmobranch species previously considered as rare and/or unknown in northern Tunisian waters. Captures of sharpnose seven-gill shark, Heptranchias perlo (Bonnaterre, 1788) and bluntnose six gills shark, Hexanchus griseus (Bonnaterre, 1788) showed that both species although they are threatened are not totally exctincted in the area. A new record of a juvenile great white shark, Carcharodon carcharias (Linnaeus, 1758) confirms one again that the central Mediterranean could be considered as a possible nursery area for this species. Additionally, captures of sandbar shark, Carcharhinus plumbeus (Nardo, 1827) and blackchin guitarfish Rhinobatos cemiculus E. Geoffroy Saint-Hilaire, 1817 are due to migrations from southern toward northern areas as a consequence of the warming of the latter areas. It may be also the case for blue shark, Prionace glauca (Linnaeus, 1758), from Algerian waters where the species is rather abundant.