Renata Ramos Gomes1,2, Thamíris Christina Karlovic de Abreu1, Maria de Lourdes Zani Teixeira1, Michel Michaelovitch de Mahiques1, June Ferraz Dias1
1University of São Paulo, Brazil - 2University of Tsukuba, Japan
Marine ecosystems are increasingly under pressure from climate change and human activities, highlighting the need for innovative approaches to their study and management. This research focuses on the Alcatrazes Archipelago, located in the Southwestern Atlantic, a transitional zone between tropical and temperate systems. This position makes the archipelago a biodiversity hotspot, combining elements from both temperate and tropical environments, and establishing it as a vital habitat for marine life within Brazil’s MPAs.
We employed an interdisciplinary approach, integrating side-scan sonar data, granulometric sediment analyses, and biological sampling to characterize the habitats and associated fish assemblages in the region over summer and winter. Sonar mosaics revealed three distinct substrate types, ranging from sandy and muddy bottoms to rocky outcrops, highlighting the spatial heterogeneity. Sediment samples confirmed the predominance of fine sands in inner regions and coarser sediments near exposed areas, reflecting hydrodynamic influences. Biological sampling yielded 2,131 individuals from 33 families, with trophic analysis revealing three distinct clusters associated with substrate variability. Species such as C. gracilicirrhus, P. punctatus, D. volitans, E. longimanus, and Z. brevirostris were highlighted as key structurers of the fish community.. The cluster analysis revealed three distinct groups, characterized by species of higher trophic levels with fewer individuals, intermediate trophic levels with a significantly higher number of individuals, and lower trophic levels with a modestly higher number of individuals.
Our findings demonstrate the effectiveness of integrating acoustic and biological methods to assess marine ecosystems and provide a methodology applicable to other ecosystems. By linking geohabitat features with ecological functions, we contribute to advancing conservation and informing MPA management.
Biography
Renata Ramos Gomes is an oceanographer with a master’s in Biological Oceanography from the University of São Paulo. Her research focuses on marine geohabitats, fish assemblages, and the influence of oceanographic and geological factors on ecosystems. Currently a PhD student at the Shimoda Marine Research Center, Tsukuba University, researching ecosystem services, functional entities, and biodiversity conservation to address the challenges posed by ocean acidification and climate change.