Movements and Submergence Patterns of Loggerhead Turtles (Caretta Caretta) in the Gulf of Mexico Determined Through Satellite Telemetry

Four loggerhead sea turtles, ranging from 56 to 93 cm in straight carapace length and from 28 to 98 kg in weight, were released in 18- to 78-m water depths and tracked for periods of 5.0 to 10.5 months in the Gulf of Mexico. Home ranges extended from 954 to 28833 km² while core areas varied from 89.6 to 4,279 km². Core areas included several petroleum and gas structures that may have been visited on a daily, weekly or monthly basis. Average submergence times of loggerheads ranged from 4.2 min in June to 171.7 min in January. The number of submergences per day was inversely proportional to the duration of submergences per day. Loggerheads spent, on the average, over 90% of their time under water in any given season. Bottom depth location of the loggerheads was significantly correlated to Galveston's mean air temperature (–0.56 < r < 0.28) and mean sea surface temperature (–0.72 < r < 0.25). Correlation was higher (–0.58 < r < 0.60) when temperatures were regressed against distance from shore. Mean swimming speeds of these loggerheads were from 0.4 to 1.4 km˙h^–1, with over 95% of the values <5 km˙h^–1.