Diversidade e distribuição de equinodermos da Plataforma Continental Amazônica

Abstract

Bycatch from trawl fishing is a major cause of population decline in fishery resources (fish, crustaceans, mollusks and echinoderms) across the globe. This impact on the environment in many cases extinguishes entire populations of aquatic organisms. In this sense, the objective of this work is to characterize the echinodermofauna accompanying the trawler trawl fishing carried out in the Amazon Continental Shelf, northern Brazil, through samplings performed in two cruises (February to March and May to June) in 2018. In all, 60 trawls were carried out in 13 fishing areas (fisheries) during this period, coding the samples at each trawl end with the fishing data. Trawling was carried out at depths of 20 to 100 meters, depending on the fishing area. In all, 4,007 echinoderms, belonging to five classes (Holoturoidea, Crinoidea, Echinoidea, Ophiuroidea and Asteriodae), 17 families and 18 species. It is noteworthy that the Asteroidea Class was the most abundant in number of families (six), individuals (1,975 ind.) And absolute species richness (11 species), however, the most frequent and abundant species was Ophioderma januarii (66.66% , with 1,860 ind.). Additionally, the first record of the Thyone fusus holoturium, from the family Phyllophoridae, is highlighted for the Brazilian coast. Moreover, it is noteworthy that, unlike the other Brazilian regions - which occurs the predominance of the Ophiuroidea class -, in the Amazon Continental Shelf, the Asteroidea class predominated. Of the fisheries analyzed, “Nº5” presented the highest richness and diversity, being the “Nº6” fishing with the highest evenness. Comparison by substrate had indicates that there is no difference in echinoderm composition between medium, fine sand and mud substrates, however, they differ from muddy sand. In this study, it was found that there is a diversity of echinoderms (18 species) that are impacted by the trawl fishing conducted on the Amazon Continental Shelf, also reporting the first record of the Thyone fusus holoturium for the Brazilian coast. It is emphasized that there is a need for further studies with the region's echinoderm fauna, such as population biology of the species, so that we will have an overview of the impact on the populations of these organisms.