Response of turtle hatchlings to light emitting diodes at sea

Abstract

It is well known that light pollution disrupts the early dispersal of marine turtles. But now, light emitting diodes (LEDs) are replacing traditional lights, however, we know little about how they influence hatchling dispersal. Here, we used acoustic telemetry to assess the early in-water dispersal and predation rates of hatchlings in response to different intensities of LEDs ranging from 10 to 120 W. We found no effect of LEDs on hatchling bearing when lights were in the direction they dispersed under ambient conditions. When LEDs were not in their usual direction of travel, variability in mean bearing increased, and a change in bearing occurred with the highest light intensity. We found weak evidence that predation was also higher at this light intensity compared to ambient, and also in two of the lower light intensities (10 and 30 W), but only on one experimental night. We were unable to find a relationship between hatchling speed and time spent in the tracking area with light intensity. However, reduced sample sizes (due to predation) might have affected our ability to detect effects. Although more effort is required to increase the confidence in our findings, LEDs disrupted hatchling dispersal and are therefore likely to negatively affect their survival.