TITLE:
Stress Biomarkers in the Giant Manta Mobula birostris Associated to Tourism in the Revillagigedo National Park, Mexico
AUTHORS:
Carolina Hernández-Navarro, Fernando R. Elorriaga-Verplancken, Felipe Galván-Magaña, Guillermo Valdivia-Anda, Renato Peña, James T. Ketchum, Edgar M. Hoyos-Padilla
KEYWORDS:
Catalase, Conservation, Elasmobranchs, Glycogen, Oxidative Stress
JOURNAL NAME:
Open Journal of Veterinary Medicine,
Vol.13 No.7,
July
27,
2023
ABSTRACT: A constant increase in dive tourism over the past years in the Revillagigedo National Park, Mexico, could result in a stressful scenario for giant mantas (Mobula birostris). The purpose of this study was to determine the degree of oxidative stress in terms of changes in catalase units (CAT) and muscle glycogen concentration in this species during two periods of different tourism intensity in this protected area. A total of 21 muscle biopsies were collected in March (peak tourism) and November (lower tourism), 2019. Stress biomarkers were analysed by commercial kits from the company Cayman Chemical. Oxidative stress (catalase activity) was significantly higher during the period with lower tourism (p = 0.002), compared to the period with more tourism, suggesting the presence of the general adaptation syndrome. In males, there was a significant difference (p = 0.0005) in oxidative stress between periods of different tourism intensity, suggesting that the reproductive season may be a stressor. Morphotypes showed different oxidative stress (p = 0.031); however, the reason is unknown. No statistical differences were detected in glycogen concentrations between the tourism periods (p = 0.123), probably because this polysaccharide is not a proper indicator of chronic stress in giant mantas. Based on these findings, giant mantas may have an adequate response in terms of oxidative stress due to an increase in tourism; however the observed increase in catalase suggests that it is within the tolerance range of these organisms.