LAUSR

The temperature in the South Atlantic underwent an increase from 1948 to 2016, and the Brazilian coast is very likely suffering from climate change. We examined temporal shifts in the abundance of the fish fauna that inhabit shallow waters and aimed to associate these shifts with climate effects. We selected candidate species according to changes in their relative abundance over four decades (1980s, 1990s, 2000s, 2010s) in a transition area between the tropical and subtropical regions in southeastern Brazil. Forty-seven species exhibited changes in abundance during the study period. Several small pelagic/planktophagous clupeoids (Anchoa lyolepis, Anchoa tricolor, Harengula clupeola, and Sardinella brasiliensis) reacted strongly to climate change with rapid population growth, whereas others (Anchoa marinii, Anchoviella brevirostris, Anchoviella lepidentostole, and Lycengraulis grossidens) decreased in relative abundance or disappeared. Some tropical species appear to be moving to this transition zone (e.g., Achirus lineatus, Ctenogobius boleosoma, and Haemulopsis corvinaeformis) because they appeared or increased populations. Conversely, subtropical species (e.g., Genidens barbus, Platanichthys platana, Boridia grossidens, and Trachinotus falcatus) decreased populations or disappeared, probably moving southward to more favorable areas, consistent with warming. This is the first estimation of climate change impacts on the southwestern Atlantic nearshore fishes and contributes as support for management policies.