Amanay and El Banquete seamounts (Canary Islands): Vunerable Marine Ecosystems (VMEs) spatial distribution

Abstract

Amanay and El Banquete Seamounts (Southern Fuerteventura) is one of the areas chosen to be depicted in the frame of INDEMARES project. The midpoint of the study area is located at 25 km from Fuerteventura and 65 km from Gran Canaria. Methodology approach complies with a multidisciplinary perspective, having described the area from geological, oceanographic, biological and fisheries points of view. Habitat identification and mapping has been possible through intense sampling and the use of habitat suitability modeling. Species structuring sensitive habitats have played a leading role, since those habitats inventory and mapping were the project’s main aim. Direct samplers have been complemented with visual samplers, the latter permitting a higher sampling effort without increasing benthic habitat impact. Several types of communities have been identified as “Habitat 1170, Reefs”, following Annex 1 from Habitats Directive (Council Directive 92/43/CEE) from European Union, representing VMEs. We have combined various types of multivariate analyses to describe the structure and spatial distribution of benthic communities, to analyze the relationship between these communities and environmental parameters, and subsequently, to build a community distribution model to predict the spatial distribution of the communities, creating community distribution maps covering the entire area. As a result of the analysis, we have identified, at circalittoral zone, Antipathella wollastoni (Gray, 1857) black coral real forests at rocky bottoms. Regarding the bathyal zone, there are rocky bottoms with anthipatarians, other with big size hexactinellid sponges (Asconema setubalense Kent, 1870), frequently seen at rocky escarpments and outcrops. We also find at this depth Callogorgia verticillata (Pallas, 1766) and Narella bellissima (Kükenthal, 1915) erect sea fans real forests, accompanied by Bebryce mollis Philippi, 1842 and Eunicella verrucosa (Pallas, 1766) high densities. Pheronema carpenteri (Thomson, 1869) and Paramuricea biscaya Grasshoff, 1977 appear on rocky outcrops from 500 m down to 1500 m. Two kinds of VMEs are found from 500 m to 1000 m, isidid corals and lithistid sponges (Leiodermatium-Neophryssospongia), siliceous sponges mixed on rocky bottom silted up with sediments at upper bathyal zone. This community mixes with anthozoan Viminella flagellum (Johnson, 1863) from 500 m down to 1600 m, where we can also find Corallium niobe Bayer, 1964 and Corallium tricolor (Johnson, 1899) deep water coral reefs. Dendrophyllia cornigera (Lamarck, 1816) and Phakellia ventilabrum (Linnaeus, 1767) are remarkable 1170 habitat communities cohabiting with deep water white corals Lophelia pertusa (Linnaeus, 1758) and Madrepora oculata Linnaeus, 1758 at lower continental shelf and upper slope rocky bottoms. Here we can also find dead coral framework, and at western El Banquete, we highlight the presence of Solenosmilia variabilis Duncan, 1873, another coldwater white coral.