Mercury Concentration in Epipelagic and Mesopelagic Fishes from the Western Equatorial Atlantic Ocean

We analyzed mercury concentrations in two epipelagic fish species Diodon eydouxii (Pelagic Porcupinefish) and Hirundichthys affinis (Fourwing Flyingfish) and one mesopelagic species Howella atlantica (Atlantic Pelagic Basslet) from the Western Equatorial Atlantic Ocean (WEAO), examining their relationship with total length. Mercury concentrations varied significantly, with the highest levels in H. affinis. Two species showed a moderate positive correlation between Hg levels and body size. This study provides the first data on Hg bioaccumulation in these species from the WEAO and highlights the need for larger sample sizes and broader age ranges to better understand mercury transfer in pelagic food webs.