*3.4. Seamounts*

Mediterranean seamounts also host habitat-former species, such as the deep-water glass sponges, sea fans and sea pens, antipatharians—which form large forests up to epibathyal depths—and cold-water corals, such as *Dendrophyllia cornigera* or the white corals *M. oculata* and *D. pertusum*, which thrive at bathyal depths (e.g., [94,134,135]). Due to the topographic and hydrographic conditions allowing the presence of habitat-former species, the seamounts act as biodiversity hotspots, and attract bentho-pelagic fish and migratory species, such as tuna, swordfish, sharks, and cetaceans, as well as several demersal fishery resources [68,76].

The Ulisse Seamount (Ligurian Sea) is a fishing ground for semi-professional and recreational fishermen targeting *P. bogaraveo*, *M. merluccius*, *P. americanus*, pink spiny lobster (*Palinurus mauritanicus*), swordfish (*Xiphias gladius*), and red seabream (*Pagellus acarne*) [136]. In the 1970s, according to the number of hooks employed on the fishing line, the catches were up to several hundreds of kilos, represented by wreckfish, blackspot seabream, bluntnose sixgill sharks, and European conger. A total of 120 wreckfish were caught between 1972 and 1975, before their complete disappearance from the catch data [20].

Accidental by-catch, mainly represented by the large arborescent primnoid anthozoan *Callogorgia verticillata*, provided the first evidence of the existence of coral forests on the summit of the Ulisse Seamount [20].

*A. foliacea* and *A. antennatus* have been reported for other Mediterranean seamounts and banks [68], including the Baronie Seamount located off the northeastern coast of Sardinia [137], representing a site of particular biological and economic interest. Several commercial species—such as the common squid (*Loligo vulgaris*), *P. edwardsii*, *H. dactylopterus*, *A. foliacea*, *A. antennatus*, *G. melastomus*, and *P. blennoides*—have been caught on this seamount [137].

The occurrence of deep-water shrimps (e.g., *A. foliacea*, *A. antennatus*, and *P. martia*), scleractinian corals (e.g., *Caryophyllia calveri*, *Desmophyllum dianthus*), and high densities of other invertebrates was reported in [138] from the Eratosthenes Seamount in the Levantine Basin. In this basin, the presence of sharks (e.g., *G. melastomus* and the spiny dogfish, *Squalus acanthias*), the greater forkbeard, and commercially important deep-sea shrimps (e.g., *P. martia*, *A. foliacea*, and *A. antennatus*) has also been reported for the Turgut Reis Bank [139].

The occurrence of several shark species (e.g., *Prionace glauca*, *H. griseus*, *Cetorhinus maximus*, *Carcharodon carcharias*, *Isurus oxyrhincus*, *Carcharhinus brevipinna*, *Lamna nasus*, *Odontaspis ferox*, and *Sphyrna lewini*) has been detected in the sea area close to the Alcione and Casoni seamounts in the South Tyrrhenian Sea [140].

In the Seco de los Olivos Seamount (western Mediterranean), several commercial species are caught with different fishing techniques, impacting benthic habitats and species [141]: the blue whiting, blackbelly rosefish, silvery pout (*Gadiculus argenteus*), and European hake with otter trawl; *Pagellus* spp., blue whiting, red scorpionfish (*Scorpaena* spp.), and mullets (*Mullus* spp.) using set gillnet; soldier shrimp (*Plesionika* spp.) with traps; and blackspot seabream using bottom longline. In addition, recreational fishing is also carried out on this seamount—mostly on the steeper slopes of the surrounding ridges, targeting the grey grouper (*Epinephelus caninus*) [141].
