Reconstructing the history of the sand tiger shark (Carcharias taurus) in the Mediterranean Sea

Abstract

Sharks are globally exposed to several anthropogenic threats, which, in many cases, have severely reduced their distribution and have impacted populations. In the Mediterranean Sea, because of its long history of exploitation and the relatively short span of scientific monitoring, reconstructing shark baselines is challenging. Many vulnerable species declined in population abundance and geographic distribution before it was possible to adequately track these changes. Consequently, for many of these species, current conservation assessments are now suffering from a severe case of shifting baseline syndrome, whereby their historical occurrence in the area is questioned. The sand tiger shark (Carcharias taurus) is one of these cases. Characterized by high philopatry, restricted home range, and low interchange between populations, its Mediterranean population may have been severely impacted by the high historical fishing pressure in the region before scientific monitoring began. In this study, the history of the abundance and distribution of C. taurus in the Mediterranean Sea was reconstructed through a comprehensive search of occurrence records in the literature and in museum collections. Between 1810 and 2008, 31 occurrence records and 54 publications provided information on the presence of the species in the area. These records were sparse but systematic over time and indicated occurrence hot spots in the south‐western Mediterranean Sea and in the eastern Adriatic Sea. The presence of ten sightings of juveniles from a total of 18 sightings with length information suggested local parturition. Habitat and extinction models indicate that the area has suitable oceanographic conditions for the occurrence of the species and that the species cannot be considered extinct in the Mediterranean Sea. Our study suggests that there is still hope for the recovery of the species and underlines the crucial role of historical investigations to reconstruct the history of large elasmobranchs in the Mediterranean Sea.

Filling the Gap and Improving Conservation: How IUCN Red Lists and Historical Scientific Data Can Shed More Light on Threatened Sharks in the Italian Seas

“…Even though applying historical ecology to marine environments has become more common in the last two decades [18,39,40], global studies focusing on cartilaginous fishes have been limited [41][42][43][44][45][46]. This lack of information is strongly evident for the Mediterranean Sea, [18,[28][29][30][47][48][49]. Considering Italian waters, historical knowledge of cartilaginous fishes is not only limited, but is also fragmented.…”

“…Originally designed for landscape research, this scientific approach has been recently applied to the marine environment as well, focusing particularly on fishery resources [19][20][21][22]. From this point of view, even though the Mediterranean Sea is commonly regarded as the cradle of Western civilization [11], historical changes in its marine realm are less well understood [23,24], and historical research on cartilaginous fishes remains very limited and fragmented [25][26][27][28][29][30].…”

From Extermination to Conservation: Historical Records of Shark Presence during the Early and Development Phase of the Greek Fishery

“…In the present study, a thorough review of anecdotal references related to shark presence aims to evaluate shark–human interactions in the Greek waters during the early and developmental phase of the fisheries (1900-early 1980s). This effort will close the historical gap in knowledge on shark populations in the Eastern Mediterranean [ 11 , 12 ], and the data gathered could be used in the MEDLEM database, a repository of information on large elasmobranchs in the Mediterranean and Black seas [ 13 ]. It can also be used in assessments for the Red List by the International Union for Conservation of Nature (IUCN), which helps to understand the historical presence and distribution of species.…”

Reply to Soldo, A.; Lipej, L. Comment on “Balàka et al. Updated Checklist of Chondrichthyan Species in Croatia (Central Mediterranean Sea). Biology 2023, 12, 952”

“…Since the 19th century, five records of Carcharias taurus have been reported from Croatia [13], with only one record being supported by photographic evidence [12]. We were able to obtain an additional photo of the same specimen (Figure 7 [1]) and identified it as O. ferox based on characteristics related to its color pattern, dorsal fin position, and eye size, all of which have been deemed reliable taxonomic features to identify both species [14][15][16].…”