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Abstract
The Mediterranean Large Elasmobranchs Monitoring (MEDLEM) database contains more than 3,000 records (with more than
4,000 individuals) of large elasmobranch species from 21 different countries around the Mediterranean and Black seas, observed
from 1666 to 2017. The principal species included in the archive are the devil ray (1,868 individu...
Context in source publication
Context 1
... information' spatial coverage is more complete and more capillary in the Adriatic, Tyrrhenian, Aegean and Balearic seas and the Strait of Sicily. The south-central and south-western Mediterranean sectors provided less information, probably as a result of lower coverage of the collaborative research centres (Fig. 2). The great white shark (C. carcharias) has been reported throughout the Mediterranean with greater frequency in the northern Adriatic Sea (FAO-GFCM's Geographic Sub Area [GSA] 17), Straits of Sicily (GSA 16) and Tyrrhenian Sea (GSA9). It is also reported from Tunisian waters (Bradaï & Saidi, 2013), Turkish waters and the Marmara Sea ...
Citations
... In the case of the Mediterranean Sea, many authors have documented that dolphins 12 , sea turtles 13 , sharks and rays 14,15 interact with and are incidentally taken by different types of fisheries, including trawlers, longlines, and gillnets 16 . Nevertheless, there is little quantitative data available on historical bycatch data of this marine megafauna and, only recently, few authors have started to share time series of Mediterranean fishery data in public repositories [17][18][19][20] . ...
Fisheries bycatch is recognised as a global threat to vulnerable marine megafauna and historical data can contribute to quantify the magnitude of the impact. Here, we present a collection of three datasets generated between 2006 and 2019 by a monitoring programme on marine megafauna bycatch in one of the main Italian fisheries, the northern central Adriatic midwater pair trawl fishery. The three datasets consist of: (i) monitored fishing effort; (ii) bycatch and biological data of dolphins, sea turtles and elasmobranchs; (iii) and dolphin sightings. Some information included in these datasets has already proved to provide a unique opportunity to estimate total incidental capture of species of conservation concern and trends of their relative abundance over time in the northern - central Adriatic Sea. These datasets are expected to be considered by different end users to improve the conservation of species and fishery management approaches to assess the impact of a fishery on species of conservation concern.
Galeus melastomus is the most common Pentanchidae in the Mediterranean Sea. A scavenger and opportunistic feeder, and despite the wide distribution, little is known about its feeding habits in Italian waters. The main purpose of this study was to investigate the diet of the blackmouth catshark by analysing the stomach contents. The specimens analysed were obtained from five populations of the Tyrrhenian and of the Ionian Seas, collected from a depth between 40 and 700 m. A total of 259 stomachs were analysed. The stomach contents were grouped into macro-categories and identified to the lowest taxonomic level possible. Crustaceans such as Parapenaeus longirostris, the Cephalopods Heteroteuthis dispar and Onychoteuthis banksii, and Osteichthyes, mostly Myctophidae, were identified. Plastic debris was also found among the stomach contents and classified according to its colour and shape. Osteichthyes represent the most abundant item (44%), above all the Myctophidae family, except for the catshark population from Tuscany, in which the most frequent species were Cephalopods, such as Abralia veranyi and Heteroteuthis dispar. Differences in the plastic debris contents were also observed between the Tuscany population and other populations. These could be explained as a probable consequence of the different depths at which the blackmouth catshark populations were sampled.
The lack of historical data on shark presence, distribution, and status in the Eastern
Mediterranean undermines efforts to manage and protect their populations. An exhaustive review of anecdotal references related to shark presence during the early and development phase of Greek fisheries (1883–1983) was conducted. In the early-20th century (1912), the first sighting of the presence of a dead shark was reported in the Ionian Sea. Later on, the presence of sharks gradually increased up to 1969, with most records being more frequent for the Aegean Sea, whereas the number of sharks being sighted declined leading up to the middle of 1980s. The increase in shark attacks during the mid-20th century led to a calling for culling of sharks in co-operation with the competent authorities promoting the permission to hunt sharks with firearms and offering rewards for killed individuals. A high number of these observations potentially resulted from shark attacks on people, whereas this is
not currently evident. This is an indicator of the lower abundance of sharks in modern times and subsequently an alteration in the way that our current modern society is approaching the protection of such vulnerable species.
The Mediterranean Sea is a renowned biodiversity hotspot influenced by multiple interacting ecological and human forces. A gap analysis on the biology of Mediterranean marine fishes was conducted in 2017, revealing the most studied species and biological characteristics, as well as identifying knowledge gaps and areas of potential future research. Here, we updated this gap analysis five years later by reviewing the literature containing information on the same eight biological characteristics, namely length-weight relationships, growth, maximum age, mortality, spawning, maturity, fecundity and diet, for the 722 fish species of the Mediterranean Sea. The results revealed a considerable knowledge gap as 37% of the species had no information for any of the studied characteristics, while 13% had information on only one characteristic. Out of all the biological characteristics, the smallest knowledge gap was found in the length-weight relationships (studied for 51% of the species, mainly in the eastern Mediterranean), while the least studied characteristic was mortality (studied for 10% of the species). The western and eastern Mediterranean Sea were leading forces in data collection exhibiting the narrowest gaps between current and desired knowledge. The most studied species across the entire region were the highly commercial European hake ( Merluccius merluccius ), red mullet ( Mullus barbatus ), European anchovy ( Engraulis encrasicolus ), European pilchard ( Sardina pilchardus ), common pandora ( Pagellus erythrinus ), and annular seabream ( Diplodus annularis ). The knowledge gap has shrunk by 6% during the last five years, with 40 new species having at least one study on their biology. Moreover, research has slightly shifted towards species that have been traditionally neglected, e.g., sharks, rays and chimaeras (chondrichthyans). It is recommended that research becomes less focused on commercial species and more targeted towards the identified gaps, vulnerable species (e.g., deep-sea species and chondrichthyans) and species that could potentially pose a threat (e.g., non-indigenous species) to the ecosystems of the everchanging Mediterranean Sea.
One shark was landed at the Naval Base Pasha Liman, Bay of Vlore, Albania, the Adriatic Sea. Photographic records only enabled the specimen to be placed in family Odontaspididae or Carchariidae. Later examination of the preserved head, dry jaw and dentition identified the specimen as Odontaspis ferox . This is a rare record and the northernmost Mediterranean observation of this species, and the first Adriatic record for several decades.
