Home ranges of East Pacific green turtles Chelonia mydas in a highly urbanized temperate foraging ground

Green sea turtles Chelonia mydas use coastal areas as foraging grounds for the majority of their lives. Human development of coastlines is increasing, but the effects of urban development of foraging grounds on green turtles are poorly understood. We used acoustic telemetry to determine home ranges of green turtles during 2009 to 2011 in San Diego Bay, California, USA, which is a highly urbanized temperate foraging area. Adult and juvenile turtles (n = 25, straight carapace length = 54.9 to 102.5 cm) were tracked for up to 370 d. Based on the fixed kernel densities of 15 turtles, we found individual home range areas (95% utilization distribution) were 2.09 to 8.70 km(2) (mean +/- SE = 5.51 +/- 0.57 km(2)), where each turtle used 1 or 2 core activity areas (50% utilization distribution). The home ranges of all turtles were exclusively in the southern portion of San Diego Bay, where eelgrass Zostera marina is abundant and where human activity is the lowest within the bay. Core activity areas coincided with eelgrass distribution or occurred adjacent to the warm water-effluent outfall of a power plant. Results from our study suggest that south San Diego Bay serves as important turtle habitat within the bay. Future monitoring is required to document the potential effects of changing environmental conditions, including closure of the power plant, on green turtles residing in San Diego Bay.