Tropicalization of demersal megafauna in the western South Atlantic since 2013

• Published in: Communications earth & environment Vol. 3; no. 1; pp. 1 - 13
• Main Authors: Perez, Jose Angel Alvarez, Sant’Ana, Rodrigo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.12.2022; Nature Portfolio
• Subjects: Biomass; Bottom water; Composition; Harbors; High temperature; Marine ecosystems; Megafauna; Ocean temperature; Ocean warming; Species composition; Temperature; Temperature preferences; Water temperature; Brazil; United States > US; Atlantic Ocean
• ISSN: 2662-4435; 2662-4435
• DOI: 10.1038/s43247-022-00553-z

Temperatures in the southwest South Atlantic Ocean have increased over recent decades due to changes in Brazil's Current dynamics affecting marine ecosystems. However, the effects of ocean warming on demersal fauna in the region are poorly understood. Here, we analyse megafauna species composition, and changes in biomass of species with warm- and cold-water affinities for 29,021 commercial demersal catches landed in the harbours of Santa Catarina state, Brazil, between 2000 and 2019. We find evidence of megafauna tropicalization in the Brazilian Meridional Margin during this period. The mean temperature of catches has increased sharply since 2013, with the averaged optimal temperature preferences of all species in commercial catches in one year increasing at a rate of 0.41 °C yr −1 . These changes in the mean temperature of the catch correlate well with model-based bottom water temperatures (with 0 and 1-year time-lag) and transport volumes of the Brazil Current (with 3 and 4-year time-lag).