Noise Pollution

A loggerhead turtle, injured in a boat collision is
treated at a rescue centre in Greece. (WSPA)

Over the past 30 years there has been a documented increase in ambient sound levels (9-to 10-dB) in some coastal marine environments. With the increase in the usage of recreational boats in the last decade and additional new sources such as seismic exploration are increasing worldwide. These new anthropogenic sources all contribute to pervasive noise levels in marine areas.

Sea turtles have an ability to perceive low-frequency sound (mainly below 1000Hz) Exposure to low-frequency sound emitted underwater by anthropogenic sources can have direct influence on sea turtle health and ecology. Little is known about the potential effects of noise exposure on the short-term or longer-term behaviour and health of sea turtles.

Observed sresponses of sea turtles to low-frequency signals include: agitated behaviour, abrupt body movements, startle responses, changes in swimming patterns and orientation.

Prolonged exposure could potentially affect sea turtles by encouraging avoidance behaviour; increasing stress and aggression levels; causing physiological damage to the ears; altering surfacing or diving rates or confounding orientation cues.

Source: Samuel, Y., Morreale, S., Clark, C., Greene, C., Richmond, M. (2005) Underwater; low-frequency noise in a coastal sea turtle habitat. J. Acoust. Soc. Am. 117 (3) p.p. 1465-