Information
on ocean scale drivers of methylmercury levels and
variability in tuna is scarce, yet crucial in the context of anthropogenic
mercury (Hg) inputs and potential threats to human health. Here we
assess Hg concentrations in three commercial tuna species (bigeye,
yellowfin, and albacore, n = 1000) from the Western
and Central Pacific Ocean (WCPO). Models were developed to map regional
Hg variance and understand the main drivers. Mercury concentrations
are enriched in southern latitudes (10°S–20°S) relative
to the equator (0°–10°S) for each species, with bigeye
exhibiting the strongest spatial gradients. Fish size is the primary
factor explaining Hg variance but physical oceanography also contributes,
with higher Hg concentrations in regions exhibiting deeper thermoclines.
Tuna trophic position and oceanic primary productivity were of weaker
importance. Predictive models perform well in the Central Equatorial
Pacific and Hawaii, but underestimate Hg concentrations in the Eastern
Pacific. A literature review from the global ocean indicates that
size tends to govern tuna Hg concentrations, however regional information
on vertical habitats, methylmercury production, and/or Hg inputs are
needed to understand Hg distribution at a broader scale. Finally,
this study establishes a geographical context of Hg levels to weigh
the risks and benefits of tuna consumption in the WCPO.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.