Why we mind sea turtles' underwater business: A review on the study of diving behavior

For most of their lifetime, sea turtles have to organize their underwater activities around the necessity to return to the surface to breathe. This group of animals has developed extraordinary diving capacities (over 10 h of single breath-hold dives and dive depths exceeding 1200 m) that allow them to exploit oceanic and neritic habitats, and maintain their role in marine ecosystems, despite the numerous threats imposed on them by human activities. Understanding sea turtle behavior, and the extent of flexibility with which they respond to environmental changes, has been a key element of studies on sea turtle diving behavior for over 25 years. Here, I review the major outcomes of these studies, summarizing published data on dive durations and depths, and identifying the factors that influence the shape and temporal patterns of sea turtle diving. By carefully assembling existing published information in this research field, some unique features emerged (such as the ability of some turtles to rest for extended periods in the middle of the water column), as well as knowledge gaps that require further investigations (such as the behavior and diving capacity of small juvenile turtles). In addition to simply collecting and presenting existing data, this review also highlights the needs for some level of minimum standardization, especially for studies involving electronic telemetry equipment, in addition to clarifying where future effort should be focused. Ultimately, this review is anticipated to serve as a reference guide for scientists and wildlife managers alike, who seek to mitigate threats to sea turtles through specific knowledge-based conservation strategies.