Foraging plasticity diversifies mercury exposure sources and bioaccumulation patterns in the world's largest predatory fish

Gaël Le Croizier, Jeroen E. Sonke, Anne Lorrain, Marina Renedo, Mauricio Hoyos-Padilla, Omar Santana-Morales, Lauren Meyer, Charlie Huveneers, Paul Butcher, Felipe Amezcua-Martinez, David Point

Research output: Contribution to journalArticlepeer-review

Abstract

Large marine predators exhibit high concentrations of mercury (Hg) as neurotoxic methylmercury, and the potential impacts of global change on Hg contamination in these species remain highly debated. Current contaminant model predictions do not account for intraspecific variability in Hg exposure and may fail to reflect the diversity of future Hg levels among conspecific populations or individuals, especially for top predators displaying a wide range of ecological traits. Here, we used Hg isotopic compositions to show that Hg exposure sources varied significantly between and within three populations of white sharks (Carcharodon carcharias) with contrasting ecology: the north-eastern Pacific, eastern Australasian, and south-western Australasian populations. Through Δ200Hg signatures in shark tissues, we found that atmospheric Hg deposition pathways to the marine environment differed between coastal and offshore habitats. Discrepancies in δ202Hg and Δ199Hg signatures among white sharks provided evidence for intraspecific exposure to distinct sources of marine methylmercury, attributed to population and ontogenetic shifts in foraging habitat and prey composition. We finally observed a strong divergence in Hg accumulation rates between populations, leading to three times higher Hg concentrations in large Australasian sharks compared to north-eastern Pacific sharks, and likely due to different trophic strategies adopted by adult sharks across populations. This study illustrates the variety of Hg exposure sources and bioaccumulation patterns that can be found within a single species and suggests that intraspecific variability needs to be considered when assessing future trajectories of Hg levels in marine predators.

Original languageEnglish
Article number127956
Number of pages9
JournalJournal of Hazardous Materials
Volume425
DOIs
Publication statusPublished - 5 Mar 2022

Keywords

  • marine predators
  • mercury adsorption
  • neurotoxic methylmercury
  • Hg contamination

Fingerprint

Dive into the research topics of 'Foraging plasticity diversifies mercury exposure sources and bioaccumulation patterns in the world's largest predatory fish'. Together they form a unique fingerprint.

Cite this