Species distribution models of two critically endangered deep-sea octocorals reveal fishing impacts on vulnerable marine ecosystems in central Mediterranean Sea

Abstract

Deep-sea coral assemblages are key components of marine ecosystems that generate habitats for fish and invertebrate communities and act as marine biodiversity hot spots. Because of their life history traits, deep-sea corals are highly vulnerable to human impacts such as fishing. They are an indicator of vulnerable marine ecosystems (VMEs), therefore their conservation is essential to preserve marine biodiversity. In the Mediterranean Sea deep-sea coral habitats are associated with commercially important crustaceans, consequently their abundance has dramatically declined due to the effects of trawling. Marine spatial planning is required to ensure that the conservation of these habitats is achieved. Species distribution models were used to investigate the distribution of two critically endangered octocorals (Funiculina quadrangularis and Isidella elongata) in the central Mediterranean as a function of environmental and fisheries variables. Results show that both species exhibit species-specific habitat preferences and spatial patterns in response to environmental variables, but the impact of trawling on their distribution differed. In particular F. quadrangularis can overlap with fishing activities, whereas I. elongata occurs exclusively where fishing is low or absent. This study represents the first attempt to identify key areas for the protection of soft and compact mud VMEs in the central Mediterranean Sea.

Climate‐induced changes in the suitable habitat of cold‐water corals and commercially important deep‐sea fishes in the North Atlantic

“…This result corresponds to similar studies on distributions of other deep‐sea corals (e.g. Buhl‐Mortensen, Olafsdottir, Buhl‐Mortensen, Burgos, & Ragnarsson, ; Chimienti, Taviani, & Mastrototaro, ; Davies & Guinotte, ; Georgian, Shedd, & Cordes, ; Guinotte & Davies, ; Lauria et al, ; Tittensor et al, ) and deep‐sea fishes (Gomez et al, ; Parra et al, ; Ross & Quattrini, ). However, the strong autocorrelation between depth and temperature and significant correlation with other environmental and biological factors complicates efforts to elucidate the environmental parameters primarily responsible for the observed patterns.…”

“…Refugia areas were identified from binary maps built with an ensemble modelling approach and two thresholds: 10 percentile training presence logistic threshold (10th) and maximum sensitivity and specificity (MSS). Refugia areas estimated by the different models used to calculate the ensemble outputs are also shown: generalized additive model (GAM), maximum entropy model (Maxent) and random forest (RF) & Guinotte, 2011;Georgian, Shedd, & Cordes, 2014;Guinotte & Davies, 2014;Lauria et al, 2017;Tittensor et al, 2010) and deep-sea fishes (Gomez et al, 2015;Parra et al, 2017;Ross & Quattrini, 2007).…”

Benthic habitat modelling and mapping as a conservation tool for marine protected areas: A seamount in the western Mediterranean

“…The presence of habitats 10 and 11 were restricted to soft substrates located in deeper areas along the outer flanks of the seamount. The two habitat‐forming species of these habitats, Kophobelemnon stelliferum and Isidella elongata , have been observed on soft bottoms at similar depths or at even deeper depths in other regions of the Mediterranean Sea (Gili & Pagès, ; Lauria et al, ). These two filter‐feeding species that live on mud bottoms depend on medium–strong currents for the local enrichment of food availability, but they generally occur in less turbulent waters than the other more robust coral forms to avoid high sedimentation rates (De Kluijver & Ingalsuo, ; Lauria et al, ).…”

Seamounts as hot-spots of large pelagic aggregations

“…This is particularly relevant since most of the overlapping habitats areas are close to the coast and at relatively short distance from coastal fishing ports. This makes these seamounts particularly attractive for fishery exploitation (Sabatini et al, 2011;Palmas et al, 2015;Lauria et al, 2017) and thus easily subjected to one of the most commonly identified impacts on seamounts (Würtz and Rovere, 2015).…”