Blood Oxygen Stores of Olive Ridley Sea Turtles, Lepidochelys olivacea are Highly Variable Among Individuals During Arribada Nesting

A key difference among marine divers is whether or not they make use of their lung O 2 stores while diving. Sea turtles are air‐breathing divers that dive with their lungs full of air. Lung oxygen stores in sea turtles are supplemented by O 2 stored in the blood. Olive ridley sea turtles exhibit polymorphic nesting behaviors consisting in either a mass nesting behavior called arribada, where up to 25,000 turtles nest at once, or a solitary nesting behavior. We measured blood volume, hemoglobin concentration, hematocrit, plasma volume and mean corpuscular hemoglobin concentration, and estimated total blood O 2 stores in samples collected from olive ridley turtles nesting solitarily or in arribada. There were no significant differences in mean values between nesting periods, but most parameters were more variable in arribada nesting individuals than in those performing solitary nesting. Mass‐specific plasma volume did not vary among individuals but mass‐specific blood volume and blood oxygen stores varied widely, 2‐fold and 3‐fold, respectively. Blood O 2 stores represented 32% of total body O 2 stores. Under typical mean diving conditions of 26°C and high levels of activity, blood stores can confer ~14 minutes of aerobic dive times and are likely critical for the long duration, deep diving exhibited by the species. Individual differences in blood O 2 stores strongly impact estimated aerobic dive limits and may constrain the ability of individuals to respond to changing ocean temperatures. Support or Funding Information McNair Scholars and Centro Mexicano de la Tortuga