First record of copper and zinc concentrations in Sphyrna tiburo: bioindicator of Campeche, Mexico, coast health

Abstract

Zinc (Zn) and copper (Cu) concentrations were evaluated in 43 samples of liver and 77 of the muscle of the bonnethead shark (Sphyrna tiburo) as an indicator of the health status of Campeche coasts in the years 2015, 2016, and 2019. Inter-tissue comparisons consistently show a lower concentration in muscle (Zn = 19.8 ± 20.3 mg/kg; Cu = 0.67 ± 0.02 mg/kg) compared to liver (Zn = 31.0 ± 18.7 mg/kg; Cu = 3.56 ± 0.97 mg/kg). Zn concentration in the liver was influenced by sex since levels in the liver of females (34.8 ± 19.50 mg/kg) were significantly higher than in males (24.5 ± 15.95 mg/kg). A decrease in the concentration of both metals was observed over the years both in the liver (Zn 2015 = 32.5, 2016 = 31.8, 2019 = 14.7 and Cu 2015 = 3.36, 2016 = 3.89, 2019 = 3.18) and in muscle (Zn 2015 = 15.0, 2016 = 32.0, 2019 = 4.20 and Cu 2015 = 0.69, 2016 = 0.67, 2019 = 0.24). The concentration of Zn and Cu in muscle did not exceed the maximum permissible limits by international standards for human consumption (Zn = 40 mg/kg, Cu = 10 mg/kg). Therefore, S. tiburo, as a bioindicator regarding these two trace elements, currently does not represent a health risk to consumers.