Habitat Use and Behavior of the East Pacific Green Turtle, Chelonia mydas, in an Urbanized System

Abstrac Green sea turtles, Chelonia mydas, are known to inhabit populated and often urbanized areas. To understand turtle habitat use and behavior within these unique habitats, seven juvenile green turtles were fitted with acoustic transmitters (September 2012 – August 2014), of which two transmitters included an accelerometer (AP transmitter). One individual fitted with an AP transmitter was tracked using a passive acoustic array in an urbanized river, the San Gabriel River, Long Beach, CA (33°45’ N, 118°05’ W). Three additional turtles in this river and three turtles (one with AP transmitter) in a restored estuary (33°44’ N, 118°03’ W) in southern California were actively tracked for two non-consecutive 24-h periods. Those fitted with AP transmitters indicated that turtles were less active at night (0.58 ± 0.56 m/s2 and 0.50 ± 0.63 m/s2) than during the day (0.86 ± 0.63 m/s2 and 0.78 ± 0.60 m/s2) at both sites. Activity data and corresponding movements of the actively tracked turtle fitted with the AP transmitter were used to infer resting periods for other tracked individuals. Turtles rested near bridge pilings and runoff outflows in the river to potentially shelter from tidal flow. Turtles used significantly larger daily areas in the urbanized river (0.046 ± 0.023 km2) where resources may be patchier and less abundant, compared to turtles in the estuary (0.024 ± 0.012 km2) where large, dense eelgrass beds are present. Based on the habitat use and behaviors of green sea turtles, it appears that some green sea turtles are able to make use of both highly developed and restored habitats and likely benefit from certain aspects of development.