Historical and ecological drivers of the spatial pattern of Chondrichthyes species richness in the Mediterranean Sea

Meléndez, María José; Báez, José C.; Serna-Quintero, J.M.; Camiñas, Juan Antonio; Fernández, Ignacio de Loyola; Real, Raimundo; Macías, David

doi:10.1371/journal.pone.0175699

Cited by 15 publications

(11 citation statements)

References 18 publications

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“…Intermediate levels of diversity have been reported for the central Mediterranean along the coasts of Libya, Malta and Sicily and in the coastal waters of the countries bordering the Adriatic and Aegean seas. This longitudinal gradient in the species richness of chondrichthyans has been suggested by several authors , Melendez et al 2017, Bradai et al 2018). However, the results of the present work seemed not to confirm this pattern (the Strait of Sicily and the Aegean showed the largest number of species), probably because North Africa is not involved in the MEDITS programme, so diversity in this area could not be considered.…”

Section: Discussionsupporting

confidence: 72%

Spatial variability of Chondrichthyes in the northern Mediterranean

et al. 2020

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Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families), 22 batoids (3 orders and 4 families) and 1 chimaera, were detected from several geographical sub-areas (GSAs) established by the General Fisheries Commission for the Mediterranean. Batoids had a preferential distribution on the continental shelf (10-200 m depth), while shark species were more frequent on the slope (200-800 m depth). Only three species, the Carcharhiniformes Galeus melastomus and Scyliorhinus canicula and the Torpediniformes Torpedo marmorata were caught in all GSAs studied. On the continental shelf, the Rajidae family was the most abundant, being represented in primis by Raja clavata and then by R. miraletus, R. polystigma and R. asterias. The slope was characterized by the prevalence of G. melastomus in all GSAs, followed by S. canicula, E. spinax and Squalus blainville. Areas under higher fishing pressure, such as the Adriatic Sea and the Spanish coast (with the exception of the Balearic Islands), show a low abundance of chondrichthyans, but other areas with a high level of fishing pressure, such as southwestern Sicily, show a high abundance, suggesting that other environmental drivers work together with fishing pressure to shape their distribution. Results of generalized additive models highlighted that depth is one of the most important environmental drivers influencing the distribution of both batoid and shark species, although temperature also showed a significant influence on their distribution. The approach explored in this work shows the possibility of producing maps modelling the distribution of demersal chondrichthyans in the Mediterranean that are useful for the management and conservation of these species at a regional scale. However, because of the vulnerability of these species to fishing exploitation, fishing pressure should be further incorporated in these models in addition to these environmental drivers.

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Section: Discussionsupporting

confidence: 72%

Spatial variability of Chondrichthyes in the northern Mediterranean

et al. 2020

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“…Diversity is slightly lower in the northwest Mediterranean countries [2]. This spatial distribution is also shown in works of [13,14].…”

Section: Spatial Distribution Of Elasmobranchs In the Mediterranean Seamentioning

confidence: 54%

Overview on Mediterranean Shark’s Fisheries: Impact on the Biodiversity

Bradaï¹,

Saïdi²,

Enajjar³

2018

Marine Ecology - Biotic and Abiotic Interactions

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Bibliographic analysis shows that the Mediterranean Sea is a hot spot for cartilaginous species biodiversity, including sharks, rays, and chimaeras; 49 sharks and 36 rays were recorded in this region. However, they are by far the most endangered group of marine fish in the Mediterranean Sea. The IUCN Red List shows clearly the vulnerability of elasmobranchs and the lack of data; 39 species (53% of 73 assessed species) are critically endangered, endangered, or vulnerable. The biological characteristics of elasmobranchs (low fecundity, late maturity, and slow growth) make them more vulnerable to fishing pressure than most teleost fish. Overfishing, the wide use of nonselective fishing practices, and habitat degradation are leading to dramatic declines of these species in the Mediterranean Sea. In general, elasmobranchs are not targeted but are caught incidentally. In many fisheries, they are, however, often landed and marketed. A decline in cartilaginous fish species landings has been observed while fishing effort has generally increased. Better understanding of the composition of incidental and targeted catches of sharks by commercial fisheries are fundamentally important for the conservation of these populations. Moreover, problems encountered by elasmobranchs in the area are highlighted, and conservation measures are suggested.

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“…The high species richness, coupled with a high proportion of endemism, makes the Mediterranean one of the world's 'biodiversity hotspots' (Moranta et al 2008, Coll et al 2010, Lejeusne et al 2010. Environmental variables such as temperature, productivity and distance from the Strait of Gibraltar have been shown to be causes of fish species richness distribution (Ben Rais Lasram et al 2009, Meléndez et al 2017. However, this high biodiversity is presently threatened by the combined action of anthropogenic impacts, introduction of alien species and climate change (Bianchi et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Spatio-temporal trends in diversity of demersal fish assemblages in the Mediterranean

Farriols

Ordines

Carbonara³

et al. 2020

Sci. Mar.

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The high species richness, coupled with high proportion of endemism, makes the Mediterranean one of the world’s ‘biodiversity hotspots’. However, the continuous increase in fisheries in the last few decades has led to the overexploitation of their main commercial stocks. Using fishery-independent data collected under the framework of the MEDITS trawl surveys carried out over the last 20 years, we study the demersal fish diversity pattern in the Mediterranean at a large spatial and temporal scale to determine whether it is being affected by the general fishing overexploitation of the demersal resources. The detected diversity trends are compared with the spatio-temporal variation in bottom trawl fishing effort in the Mediterranean. Our results show a stability and even recovery of demersal fish diversity in the Mediterranean together with higher diversity values on the continental shelves of the Balearic Islands, Sardinia, Sicily and the Aegean Sea. At large temporal and spatial scales, the high diversity of demersal assemblages in the Mediterranean is associated with a reduction in bottom trawl fishing effort. The inclusion of species other than target ones through diversity indices is important in the implementation of an ecosystem-based fisheries management.

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Historical and ecological drivers of the spatial pattern of Chondrichthyes species richness in the Mediterranean Sea

Cited by 15 publications

References 18 publications

Spatial variability of Chondrichthyes in the northern Mediterranean

Spatial variability of Chondrichthyes in the northern Mediterranean

Overview on Mediterranean Shark’s Fisheries: Impact on the Biodiversity

Spatio-temporal trends in diversity of demersal fish assemblages in the Mediterranean

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