Species diversity, taxonomy and distribution of Chondrichthyes in the Mediterranean and Black Sea

Abstract

Species diversity assessments are an important step to evaluate the conservation status of a community, both in marine and terrestrial ecosystems. These assessments are pivotal if related to both, the constant increase of human pressure on ecosystems and the anthropogenic climate change occurring nowadays. Sharks and rays are globally threatened, and the situation is particularly alarming in the Mediterranean Sea where more than 50% of species are listed at risk of extinction by the International Union for Conservation of Nature (IUCN). In this paper, we revise and discuss the chondrichthyan species richness of the Mediterranean and the Black Sea. Through an accurate review of published taxonomic studies, historical data on species occurrence, analyses of scientific survey data and biodiversity databases and other scientific papers, we produced a revised list of species whose presence in the Mediterranean Sea is confirmed or highly probable and discussed on current taxonomic and occurrence disputes on the species that are instead rarer or claimed to be locally extinct. We listed a total of 88 species, representing 30 families and 48 genera that are currently present in the Mediterranean and the Black Sea. This number includes 48 shark species, 38 batoids, and 2 chimaeras. The review represents a reference for future conservation assessments of cartilaginous fish in the region and a guide for decision-makers when promoting the sustainable exploitation of fisheries resource within an ecosystem-based framework. This paper can help to set a baseline of the Mediterranean species and thus resolve some uncertainties regarding their conservation status, explaining the reasons for their prolonged absence in the reports. Indeed, failure to record over time may not be due to grubbing up, but because after careful review this species was not really part of the Mediterranean fauna.

Batoid Abundances, Spatial Distribution, and Life History Traits in the Strait of Sicily (Central Mediterranean Sea): Bridging a Knowledge Gap through Three Decades of Survey

“…Batoid fishes are moderately to greatly flattened and are distinguished from other elasmobranchs (non-batoid sharks) by their ventral gill slits, their lack of an anal fin, and having the pectoral fins connected to the sides of the head and trunk to form a disk [ 1 , 2 ]. In the Mediterranean Sea (herein Mediterranean), at least 38 species of batoid fishes have been reported [ 3 ]. However, long-term sources of information to assess the batoids’ exploitation status are very rare in this region [ 4 , 5 ].…”

An identification key for Chondrichthyes egg cases of the Mediterranean and Black Sea

“…These include: four sharks with two species each in the genera Scyliorhinus and Galeus; 16 skates species: three Dipturus, one Rostroraja, four Leucoraja and eight Raja genera; one belonging to the genus Chimaera, one to the genus Hydrolagus. A further egg case belonging to the resurrected species Scyliorhinus duhamelii (Garman 1913) (Soares & De Carvalho 2019) has not been considered, since the species must be definitively confirmed for the Mediterranean (Serena et al 2020).…”

Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation

“…Due to this high resource availability, the human pressure on marine ecosystems is constantly rising, thus negatively impacting their biodiversity [ 4 , 5 , 6 ]. In this context, the Mediterranean Sea is considered, at the same time, a biodiversity hotspot and one of the most threatened marine areas in the world [ 7 , 8 , 9 , 10 ]. Even though the Mediterranean basin represents only 1% of the global oceans, it is estimated that it hosts up to the 18% of the world’s macroscopic marine species, about 30% of which are endemic [ 7 ].…”