Maximising MEDITS: using data collected from trawl surveys to characterise the benthic and demersal assemblages of the circalittoral and deeper waters around the Maltese Islands

Abstract

Data from MEDITS trawl surveys in the waters surrounding the Maltese Islands were analysed to characterise the benthic and demersal assemblages of the central Mediterranean, which are only poorly known, hampering Maltese authorities in meeting legislative obligations. A total of 147 benthic species and 98 demersal species were identified. These formed four well-defined assemblages, whose structure and composition were related to depth. Total species richness and abundance of both demersal and benthic species decreased with depth. The most abundant structuring epibenthic species which characterised the identified assemblages were the tall sea pen Funicularia quadrangularis (present at depths of ca. 50–700 m), the red sea pen Pennatula rubra (ca. 100–450 m), the hydroids Lytocarpia myriophyllum (ca. 100–250 m) and Nemertesia sp. (ca. 100–600), the soft coral Alcyonium palmatum (ca. 100–400 m), and the anemone Actinauge richardi (ca. 100–600 m). These results illustrate how, in the absence of dedicated benthic mapping studies, MEDITS data can be used to provide preliminary information that would not otherwise be available.