Leonardo Mitrano Neves

The subtropical Brazilian reefs are mainly rocky habitats in a transition zone of the southwestern Atlantic Ocean, which support a rich ichthyofauna. The recent discovery of the southernmost Atlantic coral reef associated with a rhodolith bed in this area, revealed a carbonate structure that ceased its growth approximately 2,400 years ago. This finding has prompted questions regarding the ecological role and function of a coral reef even after reaching its geological senescence. This study presents a detailed compiled list of the fish fauna associated with the southernmost Atlantic coral reef known and adjacencies, through a combination of stationary Underwater Visual Census (UVC), landings of gillnet fishing, Baited Remote Underwater Video (BRUV), citizen science monitoring program, voucher specimens deposited in scientific collections, and literature review. A total of 212 taxa belonging to 71 families was recorded, distributed in 184 Actinopterygii (85.38%) and 31 Chondrichthyes (14.62%). This high reef fish richness is an indicator of the importance of the heterogeneity of reef habitats for the local biodiversity, even though the study area is under the influence of multiple uses (e.g., commercial fishing, onboard recreational fishing, spearfishing and recreational scuba diving). Management actions should therefore be directed to allow the persistence of this rich fish fauna.

This study indicates a seasonal aggregation behaviour in Blacktip (Carcharhinus limbatus) and Spinner (C. brevipinna) sharks over 6 years of data in Ilha Grande Bay, a warm temperate bay in Rio de Janeiro, Brazil. Observations from visual surveys, drone footage and Baited Remote Underwater Video (BRUV) deployments revealed mixed‐species aggregations, reaching a maximum of 113 individuals, and recorded the first instances of breaching behaviour of sharks in the Southwest Atlantic. These aggregations occurred seasonally during austral autumn and winter in a shallow cove near a nuclear power plant, partially within a no‐take marine protected area. Understanding these behaviours provides valuable insights for effective management and conservation strategies in the region.

Invasive species may compromise biodiversity and ecosystem services, and represent a steadily growing concern for coastal marine ecosystems. The marine aquarium trade (MAT) is the source of some of the world’s worst aquatic invasions, inflicting multimillion-dollar losses in infected regions. In the Southwestern Atlantic (SWA), two Indo-Pacific coral species were recently introduced as a result of the MAT and already dominate the substrate at the introduction site in Southeastern Brazil (Praia Vermelha, Angra dos Reis, Rio de Janeiro State). Herein, based on morphological and molecular evidence, we report a Caribbean native coral species likely introduced by the MAT in Praia Vermelha, Erythropodium caribaeorum (Duchassaing & Michelotti 1860). While the eradication of coral species that already have a pest status in the SWA is unlikely, we propose that the eradication of the three species still contained to their introduction sites, including E. caribaeorum, is still feasible and depends on a rapid and integrated embracement of the task by core stakeholders. Priority actions for the regulation of MAT and hobbyism in Brazil are proposed.