For many marine mammals, they must dive to varying depths to obtain the food they need for survival. For these mammals to dive, typically higher levels of myoglobin within skeletal muscle provide needed stored oxygen for ATP production to fuel swim activity. Although myoglobin amounts in the skeletal muscle of many marine mammals have been well documented, data regarding the myoglobin concentration in the swim muscles of Florida manatees is limited. These are slow-moving animals that are primary herbivores making them unique compared to other marine mammals. Elucidation of the energy-producing mechanisms within skeletal muscle used by Florida manatees for diving episodes may help provide insight into their diving physiology. To quantify myoglobin levels, epaxial muscle tissue was collected from stranded Florida manatees and further tested. Preliminary results indicate that the myoglobin level within the swim muscle of the adult Florida manatee is low in comparison to control juvenile bottlenose dolphin skeletal muscle tissue (5.06 mg/g of tissue vs. 24.31 mg/g of tissue, respectively). Lower levels of myoglobin within the swim muscles of Florida manatees could reflect their lower energy demands during submersion and the potential use of alternate ATP generating pathways to maintain diving activity. Future studies will further quantify the myoglobin levels of the skeletal muscle of the Florida manatee and additionally explore other ATP generating mechanisms to provide a broader understanding of the mechanisms fueling diving episodes in these unique marine mammals.

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