No abstract

A key difference among marine divers is whether or not they make use of their lung O2 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 O2 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 O2 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 O2 stores represented 32% of total body O2 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 O2 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