Fish Distribution and Habitat Complexity on Banks of the Strait of Sicily (Central Mediterranean Sea) from Remotely-Operated Vehicle (ROV) Explorations

PLOS ONE, Dec 2016

The Strait of Sicily was recognized internationally as an “Ecologically or Biologically Significant Area” by the Contracting Parties of the Convention on Biological Diversity in 2014. However, basic aspects of its fish diversity are still unknown and most of the information comes from traditional trawl surveys. This paper provides the first detailed description, using a Remotely Operated Vehicle (ROV), of the composition and depth distribution of the demersal fish assemblages found on banks of the Strait of Sicily and the related habitat complexity from 35 to 240 m depth. A total of 24 families and 52 fish species were recorded and depth was consistently associated with a significant proportion of the variation of the fish assemblage. The highest species richness was observed at the shallowest depth layer (0–50 m) and significantly decreased, remaining almost constant, in deeper layers. Similarly the highest abundance was recorded at 0–50 m, where C. julis represented the most abundant species, and decreased progressively throughout the whole depth gradient. Although the factor habitat complexity explained only a small proportion of the fish assemblage variation, significant differences among different degrees of habitat complexity were observed, together with a general positive trend for species richness and abundance with increasing habitat complexity. The ROV also allowed us to observe some rare or poorly known fish species such as Scorpaenodes arenai, Hyporthodus haifensis, Myliobatis aquila, Gadella maraldi, Epinephelus caninus and Lappanella fasciata. These findings show that banks serve as reservoirs for fish abundance and biodiversity and that immediate environmental conservation and management actions represent a priority not only for Italy but also for other countries which share the same area.

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Fish Distribution and Habitat Complexity on Banks of the Strait of Sicily (Central Mediterranean Sea) from Remotely-Operated Vehicle (ROV) Explorations

RESEARCH ARTICLE Fish Distribution and Habitat Complexity on Banks of the Strait of Sicily (Central Mediterranean Sea) from Remotely-Operated Vehicle (ROV) Explorations Pierpaolo Consoli1*, Valentina Esposito1, Pietro Battaglia1, Chiara Altobelli2, Patrizia Perzia2, Teresa Romeo1, Simonepietro Canese3, Franco Andaloro2 a11111 1 Laboratorio di ittiologia ed ecologia marina, Istituto Superiore per la Protezione e la Ricerca ambientale (ISPRA), Milazzo, Italy, 2 IV Dipartimento Uso Sostenibile delle Risorse, STS Palermo, Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Palermo, Italy, 3 III Dipartimento Tutela degli Habitat e della Biodiversità Marina. Istituto Superiore per la Protezione e la Ricerca ambientale (ISPRA) Roma, Italy * Abstract OPEN ACCESS Citation: Consoli P, Esposito V, Battaglia P, Altobelli C, Perzia P, Romeo T, et al. (2016) Fish Distribution and Habitat Complexity on Banks of the Strait of Sicily (Central Mediterranean Sea) from Remotely-Operated Vehicle (ROV) Explorations. PLoS ONE 11(12): e0167809. doi:10.1371/journal.pone.0167809 Editor: Carlo Nike Bianchi, Universita degli Studi di Genova, ITALY Received: June 15, 2016 Accepted: November 21, 2016 Published: December 9, 2016 Copyright: © 2016 Consoli et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This project was financed by D.R.A. Assessorato Territorio Ambiente Regione SicilianaAsse 3 Linea di intervento 3.2.1.2 of POR FESR Sicilia 2007–2013 aimed to assess the marine biodiversity in Sicily. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The Strait of Sicily was recognized internationally as an “Ecologically or Biologically Significant Area” by the Contracting Parties of the Convention on Biological Diversity in 2014. However, basic aspects of its fish diversity are still unknown and most of the information comes from traditional trawl surveys. This paper provides the first detailed description, using a Remotely Operated Vehicle (ROV), of the composition and depth distribution of the demersal fish assemblages found on banks of the Strait of Sicily and the related habitat complexity from 35 to 240 m depth. A total of 24 families and 52 fish species were recorded and depth was consistently associated with a significant proportion of the variation of the fish assemblage. The highest species richness was observed at the shallowest depth layer (0–50 m) and significantly decreased, remaining almost constant, in deeper layers. Similarly the highest abundance was recorded at 0–50 m, where C. julis represented the most abundant species, and decreased progressively throughout the whole depth gradient. Although the factor habitat complexity explained only a small proportion of the fish assemblage variation, significant differences among different degrees of habitat complexity were observed, together with a general positive trend for species richness and abundance with increasing habitat complexity. The ROV also allowed us to observe some rare or poorly known fish species such as Scorpaenodes arenai, Hyporthodus haifensis, Myliobatis aquila, Gadella maraldi, Epinephelus caninus and Lappanella fasciata. These findings show that banks serve as reservoirs for fish abundance and biodiversity and that immediate environmental conservation and management actions represent a priority not only for Italy but also for other countries which share the same area. PLOS ONE | DOI:10.1371/journal.pone.0167809 December 9, 2016 1 / 21 Demersal Fish Assemblages on Banks of the Strait of Sicily Competing Interests: The authors have declared that no competing interests exist. Introduction The Strait of Sicily is located in the central Mediterranean Sea and represents the main link between the Western and Eastern Mediterranean basins. It has a minimum width of about 150 km (between Cape Bon and Mazara del Vallo), a length of about 600 km, and a mean sill of about 400 m depth [1]. It has a highly irregular bottom bathymetry, characterized in the southwest by the wide Tunisian continental shelf and in the northeast by the Sicilian shelf. These two shelves are separated by deep water areas from which arises the volcanic island of Pantelleria [2]. The bottom of the Strait of Sicily is scattered by several submarine elevations (topographically indicated as banks) made up of sedimentary or volcanic rocks [3], that can reach up to 1000 m of height. This complex topography influences the circulation scheme of the Strait characterized by filaments, meanders and eddies, that along the shelf edge of the banks can produce upwelling, locally increasing the biological productivity [4,5] and making this area an important hotspot of biodiversity within the Mediterranean [6,7]. Furthermore, several authors highlighted the presence of important nursery and spawning areas for many fishery resources [7,8,9,10,11,12], in the Strait, mainly where banks are present. These biological features are representative of the sensitivity of this area. The protection of essential fish habitats is one of the most important issues for fishery management in the Strait of Sicily [8,13], given that the human impacts (e.g., fishery, oil exploration and extraction, maritime traffic), diffusion of non-indigenous species and climate change effects are threatening this environment in recent times [14,15]. Recently, during the 40th meeting of the General Fisheries Commission for the Mediterranean Sea (30 May 2016–03 June 2016), a multiannual management plan for the fisheries exploiting European hake and deep-water rose shrimp in the Strait of Sicily was adopted. Moreover, the whole Strait of Sicily was recognized at international level as an Ecologically or Biologically Significant Area (EBSA) by the Contracting Parties of the Convention on Biological Diversity (CBD) in 2014 (COP12, October, 2014, Pyeongchang, Republic of Korea). In addition, in 2015 during the second RAC/SPA (Regional Activity Centre for Specially Protected Areas), experts started the review of the existing literature on the Strait of Sicily [6,9,10,11,12,16,17,18,19,20,21] to assess the possibility of creating one or more Specifically Protected Areas of Mediterranean Importance (SPAMIs) including these banks. Overall, these environments are poorly investigated owing to difficulties in carrying out scientific surveys and investigations in areas characterized by a rough topography, offshore location, and a strong hydrodynamic regime [22]. Nevertheless, in the last few decades, the employment of increasingly sophisticated remotely operated vehicles (ROV) has allowed to intensify the explorati (...truncated)


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Pierpaolo Consoli, Valentina Esposito, Pietro Battaglia, Chiara Altobelli, Patrizia Perzia, Teresa Romeo, Simonepietro Canese, Franco Andaloro. Fish Distribution and Habitat Complexity on Banks of the Strait of Sicily (Central Mediterranean Sea) from Remotely-Operated Vehicle (ROV) Explorations, PLOS ONE, 2016, Volume 11, Issue 12, DOI: 10.1371/journal.pone.0167809