Impacts of coastal development on hawksbill hatchling survival and swimming success during the initial offshore migration

The impacts of coastal development on survival and swimming success were investigated for hatchling hawksbill turtles (Eretmochelys imbricata) swimming away from artificially lighted and dark nesting beaches in Barbados. The overall predation rate was 6.9%. Predation rates were not significantly affected by offshore substrate type or beachfront lighting. However, of those hatchlings leaving lighted beaches that successfully escaped predation, a significantly smaller percentage (32.9%) were able to swim the prescribed distance seawards during the observation period. Moonlight significantly improved the swimming success of hatchlings leaving lighted beaches, particularly when the moon was full, but also significantly influenced predation rates, which were highest during the full moon (12.6%). Some hatchlings released from dark beaches were attracted by lights from neighbouring beaches, which only became visible after they were a substantial distance from shore. Artificial light may override the effects of wave cues in the low wave energy conditions characteristic of leeward Caribbean beaches, making swimming hawksbill hatchlings especially vulnerable to the effects of beachfront lighting.