Work

Mercury concentrations, habitat and trophic position of Antimora rostrata and Macrourus holotrachys from South Georgia (Southern Ocean)

Year: 2025

Type: article

Abstract: Mercury (Hg) is a neurotoxic element that can harm wildlife, including in cold marine ecosystems. Hg reaches the Southern Ocean through atmospheric and oceanic currents. However, data on Hg in Southern Ocean deep-sea fishes remain scarce. Our study assessed the influence of biological and ecological factors on Hg bioaccumulation in two deep-sea species, blue antimora (Antimora rostrata) and bigeye grenadier (Macrourus holotrachys), inhabiting the South Georgia region. Specifically, we aimed to: 1) analyse the habitat and trophic position of both species; 2) understand how Hg concentrations vary between tissues (muscle, brain, liver and gills); 3) evaluate how biological (length and weight) and ecological characteristics (trophic position (δ15N) and habitat (δ13C)) influence Hg concentrations. Muscle tissue had the highest Hg concentrations in both species, while the liver in A. rostrata and gills in M. holotrachys had the lowest. Overall, A. rostrata exhibited lower Hg concentrations than M. holotrachys. No significant relationships were found between Hg concentrations and length, weight nor trophic position of A. rostrata. In contrast, M. holotrachys showed a positive relationship with length, weight and habitat. A. rostrata is a pelagic feeder, whereas M. holotrachys mostly feeds near the sea bottom, highlighting how feeding strategy and habitat influence Hg bioaccumulation. It also reveals unexpected patterns of Hg distribution among tissues, particularly in the brain, where M. holotrachys exhibited one of the highest Hg concentrations. These findings suggest that feeding strategy and habitat use play key roles in Hg transfer, with potential implications for these species and their predators.

Source: Marine Pollution Bulletin

DOI: 10.1016/j.marpolbul.2025.118856