Heavy metal contamination and hepatic toxicological responses in brown trout (Salmo trutta) from the Kerguelen Islands

Abstract

The Kerguelen Islands include various species of freshwater fish such as brown trout (Salmo trutta). These trout are among the most isolated from direct anthropogenic impact worldwide. This study was designed to analyse cadmium (Cd) and copper (Cu) concentrations in the liver of Kerguelen brown trout, and to assess the possible impacts of these metals on hepatic histopathology and oxidative stress parameters (superoxide dismutase and catalase activity and glutathione levels). Trout were caught in the Château River, the Studer Lakes and the Ferme Pond, close to the scientific station of the Kerguelen Islands, corresponding to three morphotypes (river, lake and station). Kerguelen trouts’ hepatic concentrations of Cd and Cur were similar to those reported in previous studies in salmonids populations from areas under anthropological impacts. Clear hepatic disturbances (fibrosis, nuclear alteration, increased immune response, melanomacrophage centres [MMCs]) were observed in all tested trout. A similar histo-pathological trend was observed among the trout from the three morphotypes but anti-oxidative responses were higher in the trout from the “station” morphotype. Hepatic alterations and the presence of MMCs in the livers of Kerguelen brown trout may be related to the high levels of Cd and Cu measured in this fish at all sampling sites.

• Brown trout
• freshwater
• fish
• sub-Antarctic
• liver
• biomarkers

Acknowledgements

The study was financially supported by the French Polar Institute Paul-Emile Victor (IMMUNOTOXKER programme 409) and by the French National Research Agency (ANR–RISKER programme). The authors thank the French Polar Institute for its logistical support in the Kerguelen Islands, the French Austral and Antarctic Territories Administration and the staff of the 56th mission in the Kerguelen Islands for their help with fieldwork. The authors sincerely thank Annie Buchwalter and Mohamad Alkassem for help with the English revision.