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 spe cies 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 spe cies is rather abundant.

Data‐mining social media platforms highlights conservation action for the Mediterranean Critically Endangered blue shark Prionace glauca

“…Analyses of headlines from digital magazines (n = 172) over the sampling period showed that negative perceptions significantly The distribution and habitat use of blue sharks is complex, as they display temporal and spatial segregation by sex and size, as well as broad-scale seasonal movements (Nakano & Stevens, 2008;Queiroz et al, 2012). Whereas the size and sex segregation of blue sharks has been largely described in oceanic zones (Mejuto & García-Cortés, 2005;Nakano & Stevens, 2008), little information is available from coastal areas, especially from the Mediterranean Sea (Mejuto et al, 2014;Rafrafi-Nouira et al, 2015). In this study, records of blue sharks in Italian coastal waters included individuals of all life stages, with similar size-class abundances.…”

A new record of a great white shark, Carcharodon carcharias(Chondrichthyes: Lamnidae) in the Strait of Sicily, Central Mediterranean Sea

“…Fisheries that catch both juvenile and adult specimens have been documented in Tunisian waters whilst using different gear such as longliners (FERGUSSON, 2002), trawlers and purse seiners (BRADAÏ, M. N. AND B. SAÏDI 2013) indicating the importance of the area for the Mediterranean great white shark population. The Strait of Sicily is indeed considered the "core area" of the population also playing a key role as a parturition and nursery area (FERGUSSON, 1996, SAIDI et al, 2005BRADAÏ, M. N. AND B. SAÏDI 2013;RAFRAFI-NOUIRA et al, 2015).…”

New record of a sharpnose sevengill shark Heptranchias perlo (Elasmobranchii, Hexanchidae) from the Balearic Sea, western Mediterranean Sea

“…Rafrafi‐Nouira et al . () provided information on a 990 mm L T female captured off north Tunisia in 2014 and El Kamel‐Moutalibi et al . () reported the capture of four H. perlo in the Straits of Sicily area in the 2007–2014 period.…”