Associations between total mercury, trace minerals, and blood health markers in Northwest Atlantic white sharks (Carcharodon carcharias)

• Published in: Marine pollution bulletin 2023-10, Vol.195, p.115533-115533, Article 115533
• Main Authors: Crawford, Lisa M., Gelsleichter, James, Newton, Alisa L., Hoopes, Lisa A., Lee, Cheng-Shiuan, Fisher, Nicholas S., Adams, Douglas H., Giraudo, Maeva, McElroy, Anne E.
• Format: Article
• Language: English
• Subjects: Acute phase protein; Animal biology; Bioaccumulation; Contaminants; Elasmobranch; Life Sciences; Selenium; Toxicology
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2023.115533

The ecology and life-histories of white sharks make this species susceptible to mercury bioaccumulation; however, the health consequences of mercury exposure are understudied. We measured muscle and plasma total mercury (THg), health markers, and trace minerals in Northwest Atlantic white sharks. THg in muscle tissue averaged 10.0 mg/kg dry weight, while THg in blood plasma averaged 533 μg/L. THg levels in plasma and muscle were positively correlated with shark precaudal length (153–419 cm), and THg was bioaccumulated proportionally in muscle and plasma. Nine sharks had selenium:mercury molar ratios in blood plasma >1.0, indicating that for certain individuals the potential protective effects of the trace mineral were diminished, whereas excess selenium may have protected other individuals. No relationships between plasma THg and any trace minerals or health markers were identified. Thus, we found no evidence of negative effects of Hg bioaccumulation, even in sharks with very high THg. •This study provides a baseline for total mercury in Northwest Atlantic white sharks.•Muscle THg was comparable to levels reported for other global populations.•Plasma THg levels exceeded documented concentrations by four-fold.•White sharks bioaccumulate THg in muscle and plasma proportionally.•THg bioaccumulation was not associated with any health biomarkers.