Ricardo Aguilar

Marine litter in the upper São Vicente submarine canyon (SW Portugal): Abundance, distribution, composition and fauna interactions

Marine litter has become a worldwide environmental problem, tainting all ocean habitats. The abundance, distribution and composition of litter and its interactions with fauna were evaluated in the upper S. Vicente canyon using video images from 3 remote operated vehicle exploratory dives. Litter was present in all dives and the abundance was as high as 3.31 items100m(-1). Mean abundance of litter over rock bottom was higher than on soft substrate. Mean litter abundance was slightly higher than reported for other canyons on the Portuguese margin, but lower in comparison to more urbanized coastal areas of the world. Lost fishing gear was the prevalent type of litter, indicating that the majority of litter originates from maritime sources, mainly fishing activity. Physical contact with sessile fauna and entanglement of specimens were the major impacts of lost fishing gear. Based on the importance of this region for the local fishermen, litter abundance is expected to increase.

Mediterranean hexactinellid sponges, with the description of a new Sympagella species (Porifera, Hexactinellida)

An overview is proposed of the hexactinellid sponge fauna of the Mediterranean Sea, including the description of a new species of Sympagella , S. delauzei sp. nov., collected by ROV during the exploration of deep-sea canyons of the NW Mediterranean and of deep banks and seamounts of the Alboran Sea. The type species of Sympagella , S. nux , is redescribed from specimens from the type locality. An 18S rDNA sequence of the new species was obtained and included in a phylogenetic tree of related hexactinellids. Some modifications to the classification of Rossellidae are proposed according to the new morphological and molecular data obtained during this study: the genera Caulophacus , and Caulophacella are accordingly moved from Rossellinae to Lanuginellinae.

Isidella elongata (Cnidaria: Alcyonacea) facies in the western Mediterranean Sea: Visual surveys and descriptions of its ecological role

Abstract Isidella elongata is a candelabrum-shaped alcyonacean forming important facies on the bathyal muddy bottoms of the Mediterranean Sea, currently considered a sensitive habitat and heavily impacted by deep-sea fisheries. Until a few decades ago, this facies was a widespread habitat of the deep Mediterranean seabed and I. elongata was a common species in the trawling fishery’s bycatch. Despite its current persistence in dense aggregations being very scarce, a dense facies of I. elongata was revealed during several ROV (Remotely Operated Vehicle) surveys carried out from 2010 to 2014 on the muddy bottoms between two seamounts east of Ibiza (Balearic Sea). The facies developed in an area between 480 and 615 m in depth where trawling is forbidden, with an extraordinary density of about 2300–2683 colonies/ha, representing one of the biggest facies of I. elongata currently known for the Mediterranean Sea considering the surface covered and the colonies’ density. The associated community was surveyed, with 50 taxa identified. Moreover, a canyon southwest of Formentera characterised by the presence of I. elongata together with a high trawling impact was investigated. The density of the colonies was 53–62 colonies/ha and only 19 taxa of associated fauna were observed. The results of the two areas are compared and discussed in the framework of the protection of such an important habitat.

On the occurrence of Coronaster briareus (Echinodermata, Forcipulatida, Asteriidae) in the Mediterranean Sea

The sea star Coronaster briareus (Verrill Am J Sci (Ser III), 1882) is reported for the first time from the Mediterranean Sea. A total of 26 individuals were sighted in Maltese waters during ROV surveys made in July 2015 and June–July 2016. The identity of the species was confirmed through morphological examination of a specimen collected in June 2016. This identification is discussed in the light of inconsistencies in the published descriptions of species of Coronaster recorded from the Atlantic, and of individuals belonging to this genus recorded from the eastern Atlantic and whose coloration does not match that of C. briareus or C. volsellatus (the only species of Coronaster hitherto known from the Atlantic). The presence of numerous individuals of C. briareus in Maltese waters, recorded on two occasions a year apart over a relatively large area, indicates that there is an established population. This represents a considerable expansion of the distribution range of this species, which is mostly known from the western Atlantic. Possible reasons for its presence in Maltese waters are discussed, but the dynamics of the occurrence of C. briareus in the central Mediterranean remain unknown.