Diet of the Deep-Sea Shark Galeus melastomus Rafinesque, 1810, in the Mediterranean Sea: What We Know and What We Should Know

Abstract

We reviewed literature on the diet of the Galeus melastomus Rafinesque, 1810, from the Mediterranean Sea. Specific keywords (“Galeus melastomus diet”, “feeding habits”, “trophic position”, “biology”, “deep environment adaptation”) in the principal data sources, such as Web of Science, PubMed, and Google Scholar were used. Seventeen studies conducted on the diet and trophic position of G. melastomus have been considered for Mediterranean Sea regions. The feeding habits have been analyzed in many areas of the western basin; instead, for the Tyrrhenian, Adriatic, and central Mediterranean Seas, information is outdated and fragmentary. In all investigated sub areas, the data showed that G. melastomus is an opportunistic demersal supra benthic predator, benthic feeder, and scavenger, that adapts its diet to the seasonal and geographical fluctuations of the prey availability. It occupies a generalist niche showing individual specialization. In all reviewed Mediterranean sub areas, the most important prey groups were crustaceans, cephalopods, and teleost fishes. Taxa percentage in its diet composition can vary depending on different habitats with ontogenetic development of individuals, depth (that is correlated with the ontogenetic development), seasonal availability, and distribution of different prey groups. Widening knowledge of G. melastomus feeding habits is a fundamental tool for better understand meso and bathy-pelagic ecosystems.

Deep-Water Cartilaginous Fishes in the Central Mediterranean Sea: Comparison between Geographic Areas with Two Low Impact Tools for Sampling

“…Female of the latter species has low fecundity with only one embryo and a reproductive cycle that could last two years, making this species particularly vulnerable to human impact [77,78]. The highest resilience shown by G. melastomus could be explained not only by its wide distribution, but also by its reproductive traits (i.e., egg deposition occurring throughout the year and deposition of multiple egg case) and its feeding strategy [16,75,79,80]. G. melastomus, in fact, is an opportunistic meso-predator and scavenger or generalist feeder with a broad spectrum of pray; it is capable of adapting its diet to seasonal fluctuations of pray and taking advantage of discarded material from fishing activities [16,76,80].…”

“…The highest resilience shown by G. melastomus could be explained not only by its wide distribution, but also by its reproductive traits (i.e., egg deposition occurring throughout the year and deposition of multiple egg case) and its feeding strategy [16,75,79,80]. G. melastomus, in fact, is an opportunistic meso-predator and scavenger or generalist feeder with a broad spectrum of pray; it is capable of adapting its diet to seasonal fluctuations of pray and taking advantage of discarded material from fishing activities [16,76,80]. During the MEDITS trawl surveys carried out from 2012 to 2015, the frequency of occurrence recorded for L. circularis was 8.3% in the southern Adriatic Sea and 1.7% in the north-western Ionian Sea, whereas, in the same period, L. fullonica was never collected in both areas [11].…”

Feeding Habits and the Occurrence of Anthropogenic Debris in the Stomach Content of Marine Fish from Pattani Bay, Gulf of Thailand

“…It is important fundamental information to understand the functional role of the fish community in aquatic ecosystems [ 1 , 2 , 6 ] and useful to understand the interspecific interaction of resource partitioning (e.g., habitat, food) between species [ 7 , 8 , 9 ]. Fish show a narrow range of feeding adaptation, though there are some overlaps in food selection between niches in tropical estuaries [ 2 ] and nontropical estuaries [ 9 , 10 , 11 , 12 , 13 ]. There are some studies of diet overlap, food selection, and resource partitioning of fish in tropical and nontropical regions.…”

“…There are some studies of diet overlap, food selection, and resource partitioning of fish in tropical and nontropical regions. Examples include the fish community inhabiting the bay mouth region in Thailand [ 14 ], short mackerel ( Rastrelliger brachysoma ) in a tropical estuarine environment [ 15 ], estuarine–reef habitat fish in Brazil [ 9 ], demersal fish on the continental shelf of the East/Japan Sea [ 10 ] and Southern Tyrrhenian Sea [ 16 ], deep-sea fish community in the benthic layer of the Mediterranean Sea [ 11 ], deep-sea shark ( Galeus melastomus ) in the Mediterranean Sea [ 12 ] and southern Tyrrhenian Sea [ 17 ], and diet overlap between jellyfish and juvenile fish in Alaska [ 13 ].…”

Virgin Polystyrene Microparticles Exposure Leads to Changes in Gills DNA and Physical Condition in the Mediterranean Mussel Mytilus Galloprovincialis

“…Microplastic particles have been reported in a broad range of ecosystems and organisms in the marine environment [ 4 ]. Due to currents, winds, and hydrodynamic processes, microplastic can be found in every ecosystem, even with low anthropogenic pressure, such as Antarctica [ 5 ], coral reefs [ 6 ], and deep marine environments [ 7 ]. Due to their ubiquity and small size, microplastics are bioavailable for a great number of marine organisms [ 8 ], and therefore reports of ingestion by marine animals are numerous [ 9 ], as well as their physical and ecotoxicological implications [ 10 , 11 , 12 , 13 ].…”