Evaluation of a dietary methylmercury dosing method for use in elasmobranch toxicology studies

Maria Auxiladora Sabando Plaza; Moonkyoung Cho; Sae Yun Kwon; Kady Lyons; Mi-Ling Li; Aaron Carlisle

doi:10.1016/j.marpolbul.2025.118338

Evaluation of a dietary methylmercury dosing method for use in elasmobranch toxicology studies

Mar Pollut Bull. 2025 Jun 30:220:118338. doi: 10.1016/j.marpolbul.2025.118338. Online ahead of print.

Authors

Maria Auxiladora Sabando Plaza¹, Moonkyoung Cho², Sae Yun Kwon², Kady Lyons³, Mi-Ling Li⁴, Aaron Carlisle⁴

Affiliations

¹ School of Marine Science and Policy, University of Delaware, 700 Pilottown Rd, Lewes, DE 19958, USA. Electronic address: msabando@udel.edu.
² Division of Environmental Science & Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam Gu, Pohang 37673, South Korea.
³ Georgia Aquarium, 225 Baker St NW, Atlanta, GA 30313, USA.
⁴ School of Marine Science and Policy, University of Delaware, 700 Pilottown Rd, Lewes, DE 19958, USA.

PMID: 40592097
DOI: 10.1016/j.marpolbul.2025.118338

Abstract

As mid to upper trophic level predators, elasmobranchs (sharks, skates, and rays) are known to have elevated levels of a potent neurotoxicant, methylmercury (MeHg). The lethality of MeHg across different vertebrate taxa is well established, but its sublethal effects have only been investigated in depth at the scope of human health. The sublethal effects of exposure to MeHg, which are known to impact animal physiology and behavior, remain largely undescribed in elasmobranchs. In this study, a new approach was tested for assessing bioaccumulation and the sublethal effects of MeHg in a coastal shark species over extended time periods (five months) in a spatially constrained research setting. By the end of the experiment, shark muscle in the high-dose treatment had 24.03 μg/g MeHg, while low-dose shark muscle had 10.11 μg/g MeHg, compared to the 1.18 μg/g MeHg in the muscle of control sharks. Regardless of treatment, the highest concentrations of MeHg were found within the muscle, brain, heart, and kidneys while the lowest concentrations were found in the liver, intestine, and stomach. This work provides insight into how biological processes may respond to MeHg exposure, a widespread contaminant in aquatic environments.