Spatial variation in the population structure of Lutjanus synagris and Haemulon aurolineatum along the coast of Bahia, Brazil

Lutjanus synagris and Haemulon aurolineatum are particularly important species for artisanal fisheries therefore, the objective of this study was to evaluate the population characteristics of these species in three coastal areas of Bahia, based on biometric, reproductive, and physiological characteristics, as well as to investigate the relationship between these characteristics and local environmental conditions. Lutjanus synagris exhibited a sex ratio imbalance and spatial variation in its reproductive cycle, while H. aurolineatum showed no changes in these reproductive parameters but demonstrated a tendency toward early sexual maturation, as well as positive allometric growth. These results suggest that H. aurolineatum exhibits phenotypic plasticity that may enhance adaptation to adverse environmental conditions. In locations with higher levels of oil contamination, including areas affected by the 2019 oil spill off the northeast coast of Brazil, individuals exhibited smaller body sizes and reduced physiological indices, which is consistent with the fish’s exposure to chemical stress caused by pollution. None of the species had individuals in the active reproductive phase, which may be associated with unfavorable environmental conditions. Therefore, these results highlight the need for continuous monitoring and conservation efforts for these species.