A Baseline Model For Estimating the Risk of Gas Embolism in Sea Turtles During Routine Dives

NATHAN ROBINSON; DANIEL GARCÍA-PÁRRAGA; BRIAN A. STACY; ALEXANDER A. COSTIDIS; GABRIELA S. BLANCO; CHELSEA CLYDE-BROCKWAY; HEATHER L. HAAS; CRAIG A. HARMS; SAMIR PATEL; NICOLE I. STACY; ANDREAS FAHLMAN

Frontiers in Physiology

Frontiers

Año: 2021

Sea turtles, like other air-breathing diving vertebrates, commonly experience significant gas embolism (GE) after being incidentally caught in fishing gear and brought to the surface. To better understand why sea turtles develop GE, we built a mathematical model to estimate partial pressures of N2 (PN2), O2 (PO2), and CO2 (PCO2) in the major body-compartments of diving loggerheads (Caretta caretta), leatherbacks (Dermochelys coriacea), and green turtles (Chelonia mydas). This model was adapted from a previously published model for estimating gas dynamics in marine mammals and penguins. To parameterize the model for sea turtle anatomy and physiology, we used values gleaned from both previously published literature and 22 necropsies. Next, we applied this model to data collected from free-roaming individuals of the three study species. Finally, we varied both the body-condition and cardiac output within the model to see how these factors affected the risk of GE. Our model suggests that cardiac output likely plays a significant role in the modulation of GE, especially in the deeper diving leatherback turtles. This baseline model also suggests that sea turtles are at high risk of GE even during routine diving behavior. This indicates that turtles may have additional behavioral, anatomical, and/or physiologic adaptions that were not incorporated in this model, which serve to reduce the probability of GE. Identifying these adaptations and incorporating them into future iterations of this model will further reveal the factors driving GE in sea turtles.