Symon, T.E., D.A., Murillo-Cisneros, C.J., Hernández-Camacho, T., O'Hara, R.J., Taylor, C.A., Rosado-Berrios, J.P., Vázquez-Medina & T., Zenteno-Savín (2023). Mercury and selenium concentrations in lanugo of California sea lion (Zalophus californianus) pups of the southern Gulf of California. SETAC North America 44th Annual Meeting. One Environment. One Health. Louisville, Estados Unidos de América, noviembre 12 - 16, 2023, 363.
Taryn E. Symon 1, Daniela Alejandra Murillo-Cisneros 1, Claudia Janetl Hernández-Camacho 2, Todd O'Hara 3, Robert J. Taylor 3, Carlos A. Rosado-Berrios 3, José P. Vázquez-Medina 4 y Tania Zenteno-Savín 1
Mercury (Hg) exposure can result in adverse health effects and may influence population dynamics. Selenium(Se)-Hg interactions increase the likelihood of adverse effects. Piscivorous species, such as California sea lions (Zalophus californianus), experience Hg bioaccumulation and biomagnification. Speculation exists that somemarine mammals display a greater tolerance to the adverse effects of Hg in comparison to non-piscivorousterrestrial mammals, likely in relation to the relatively high total Se concentrations ([TSe]) in prey. At LosIslotes (Gulf of California, Mexico), the total Hg concentrations ([THg]) and [TSe] in the tissues of Z.californianus have not been studied for the past two decades; the potential influence of sex and body conditionindex (BCI) on these elements, and comparisons of [THg] with toxicological thresholds of concern (TTC) areunexplored. Thus, using lanugo (hair grown in utero, represents dam diet and fetus exposure) samples obtainedin 2021, we determined the [THg], [TSe], and TSe:THg molar ratio. The [THg] ranged from 1.25-23.24 ppm,[TSe] 4.41-10.50 ppm, TSe:THg molar ratio 0.65-21.39, and BCI 0.61-1.28. Female pups (average = 7.65 ±1.33 ppm) had significantly higher [TSe] than males (6.28 ± 1.23 ppm; p = 0.004). No significant differences (p> 0.05) were observed between sexes for [THg] (median, females = 5.85 ppm; males = 4.37 ppm), TSe:THgmolar ratio (median, females = 3.11; males = 3.35), or BCI (median, females = 0.98; males = 1.01). Nosignificant correlations (p > 0.05) were observed between BCI and [THg], [TSe], or TSe:THg molar ratio.Using pinniped TTC, the majority of pups (80%) were classified as low risk ([THg] < 10 ppm); 72% of femalesand 88% of males fell into this group. These results indicate that both Hg and Se accumulate in the lanugo of Z.californianus. Studying baseline conditions of Z. californianus experiencing population increase may allowbetter interpretation of the influence of toxicants on declining populations in the Gulf of California, and may beapplicable to other species, including Steller sea lions and harbor seals, in other geographical regions.
Palabras clave: contaminación; metales; Pinnípedos; Golfo de California
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