COMMUNITY STRUCTURE AND SPATIAL DISTRIBUTION OF NOCTURNAL FISH ON A ROCKY REEF IN SOUTHWEST ATLANTIC
Channel: Encontro Recifal Brasileiro
Date: 01/07/2020

Stephanie Duarte Tabosa Delfino; Vinicius L. Soares; Caio R. Pimentel; Moysés C. Barbosa; Kurt Schmid; Tommaso Giarrizzo; Carlos Eduardo L. Ferreira; Jean-Christophe Joyeux.

Many reef fish species occupy different areas during the day and night. It is important to know how these species use their habitats, not only during the day, but also at night, to understand the structure and population dynamics and therefore manage fisheries resources in a sustainable way. Thus, using Baited Remote Underwater stereo-Video Systems (stereo-BRUVS), 33 nocturnal samples were performed in the Marine Extractive Reserve of Arraial do Cabo, Brazil, in order to describe the taxonomic and functional structure of the fish assemblages. For each sample the relative abundance and biomass of species were calculated. The influence of the environmental factors Region (influenced vs. not influenced by upwelling), Substrate (consolidated vs. unconsolidated) and Depth were assessed by Permutational Analysis of Variance (PERMANOVA). Twenty-one families represented by 576 individuals were registered. Region and Substrate significantly influenced the nocturnal ichthyofauna distribution and the biomass of functional groups. The region least influenced by the upwelling presented greater abundance and species richness in relation to the region most directly affected. In functional terms, nocturnal fish assemblages in both regions were formed mainly by sandy bottom foragers, macrocarnivores and mobile invertebrate feeders. The only threatened species detected was Zapteryx brevirostris. Although it is not targeted by fisheries, this species is intensely caught as bycatch, mainly by trawl fishing. This study is one the first to consider nocturnal components of the fish community enabling a greater understanding of the structure and distribution of these assemblage that are under heavy fishing pressure. Our data is necessary to assist new management measures, reinforcing one the extractive MPA main objectives which is to guarantee sustainable use and conservation of natural resources.