Cold‐water coral Madrepora oculata in the eastern Ligurian Sea (NW Mediterranean): Historical and recent findings

Abstract

1. Cold-water coral (CWC) ecosystems are long-lived, slow-growing and fragile, which makes them especially vulnerable to physical damage. In recent decades, CWCs have been severely threatened by fisheries, hydrocarbon extraction, pollution and other human activities.2. In the Mediterranean Sea, some investigations have been carried out on CWC ecosystems, mostly focused on their distributions within the central and eastern basins. 3. Historical reports and fishermen's maps for the eastern Ligurian Sea (NW Mediterranean) from the 1960s document the occurrence of extensive banks of living CWC, mostly Madrepora oculata, between depths of 200 and 500 m. 4. In 2013/2014, multibeam, side scan sonar (SSS) and remotely operated vehicle (ROV) surveys were carried out in that area, specifically in the Levante Canyon, to assess the occurrence, distribution and conservation status of CWC. 5. The SSS and ROV showed numerous trawl tracks and small (10 cm high), dead, buried colonies at 300-500 m. Deeper, between 525 and 575 m, dense populations of living, 1 m high colonies of Madrepora oculata were found on the flanks of Levante Canyon. The deep sites showed colonies overturned or entangled by long-line fishing activities. 6. The discovery of new CWC banks not yet heavily damaged by fishing activities, suggests that urgent measures for conservation should be taken in the Mediterranean and worldwide. The present limitation of trawl-fishing to above 1000 m depth, established by the General Fisheries Commission for the Mediterranean (GFCM) in 2005, seems to be ineffective, since CWCs are mostly located at less than 1000 m depth in the Ligurian Sea. A network of high-seas/deep-sea marine protected areas (MPAs) would favour a better strategy for protecting substantial areas of CWCs. KEYWORDS cold-water coral ecosystems, Levante Canyon, Madrepora oculata, marine protected areas, Mediterranean Sea, remotely operated vehicle, seafloor mapping

Placogorgia coronata first documented record in Italian waters: Use of trawl bycatch to unveil vulnerable deep‐sea ecosystems

“…Moreover, evidence of coral framework loss came from the SSS investigation that did not detect hardgrounds in one of the historical coral areas off Portofino appearing on the Fusco () map. A similar situation was reported for another Ligurian bathyal coral area reported by the same author; recent investigations support the hypothesis that this area no longer exists, probably due to the intensive and destructive trawling action (Fanelli et al, ).…”

“…The Ligurian records of P. coronata in the trawl discards highlight the fragility of this small CWC species as well as the risks to which the benthic community as a whole is subjected. The vertical development of the dead white coral crest offers natural protection against trawling (Bo et al, ; Fanelli et al, ). Nevertheless, the frequency of occurrence of the species in the trawl discards is surprisingly high.…”

“…About half of the species are CWCs sensu strictu , being the principal structuring components of complex deep benthic ecosystems, namely white coral facies (e.g. Chimienti et al, in press; Fabri et al, ; Fanelli et al, ; Freiwald, Beuck, Rüggeberg, Taviani, & Hebbeln, ; Orejas et al, ; Taviani et al, ; Tursi, Mastrototaro, Matarrese, Maiorano, & D'Onghia, ) as well as forests of other arborescent anthozoans dominated by large gorgonians and antipatharians (e.g. Aguilar, Pastor, Garcia, Marin, & Ubero, ; Bo et al, , 2015; Cartes, Lo Iacono, Mamouridis, López‐Pérez, & Rodríguez, ; Fabri et al, ; Giusti et al, ; Gori et al, ; Pardo, Aguilar, García, de la Torriente, & Ubero, ).…”

Massive bioconstructions built by Neopycnodonte cochlear (Mollusca, Bivalvia) in a mesophotic environment in the central Mediterranean Sea

“…At both sites, most of the bioconstructions were composed of dead specimens of N. cochlear. Live specimens were present in scattered clusters of a few individuals (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) grafted onto the superficial layer of the bioconstruction. Specifically, the large-scale analysis of the resin slices showed how the general framework of the bioconstruction was always shell supported and derived from the complex superposition of new valves on the preceding ones ( Fig.…”

New sites expanding the “Sardinian cold‐water coral province” extension: A new potential cold‐water coral network?

“…Thus, conservation of CWC ecosystems has received considerable attention, and several protection measures have been put in place, especially in relation to fishing activities (Davies, Roberts, & Hall-Spencer, 2007;Huvenne, Bett, Masson, Le Bas, & Wheeler, 2016 It is essential to develop a good understanding of the spatial distribution of CWC reefs and of those factors controlling their dynamics across biogeographic regions. Since 2004, the presence of "six" discontinuous "provinces" of living CWC banks has been extensively documented in the Mediterranean Sea (Fanelli et al, 2017;Taviani, Freiwald, & Zibrovius, 2005, Taviani et al, 2011Vertino et al, 2010). Along the Sardinian continental margin, prior to 2015, the presence of CWC was only documented through late Pleistocene age fossils (Delibrias & Taviani, 1984), when remotely operated vehicle (ROV) surveys revealed the presence of living CWC banks in the Nora canyon, off the south Sardinia continental margin.…”