Impacts of motorboat noise on the parental-care behaviours of two species of coral-reef damselfish (Pomacentridae).

Abstract

Anthropogenic noise-pollution from human activities, such as construction, oil exploration, and vessel traffic, is a growing threat to marine environments. A range of noise-induced effects on the physiology and behaviour of fish are known, but only a few studies have investigated the effects of noise on behaviours with a direct relationship to fitness, such as parental care. Furthermore, most research has tested the responses of captive fish using short-term playback of noise recordings. More evidence is required regarding impacts of noise directly from the source in natural conditions, and on long-term effects from repeated exposures. The current study investigated the impacts of short-term and long-term (repeated) exposure to motorboats on the parental-care behaviours of two species of coral-reef damselfish (family Pomacentridae). Short-term motorboat-noise exposure caused Ambon damselfish Pomacentrus amboinensis to reduce egg tending in favour of increased vigilance compared to an ambient-sound control. Long-term repeated motorboat exposure did not cause spiny pullers Acanthochromis polyacanthus to change their baseline larval-defence behaviours. However, shortterm noise did cause a temporary increase in anti-intruder display rate, and the parents showed sensitisation in this response over the course of a month-long exposure regime, compared to ambientsound control nests. Impacts of motorboat noise on the parental-care behaviours of fish could lead to reduced survival or compromised development of offspring, so decrease reproductive success. It is therefore important that policymakers and motorboat users are presented with comprehensive evidence of the real-world effects of motorboat noise in order to develop effective mitigation strategies. More evidence is required on the long-term effects of repeated and chronic anthropogenic noise on fish to best inform practice, particularly in relation to fitness-influencing behaviours.

Date of Award	1 Oct 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Andrew N Radford (Supervisor) & Steve Simpson (Supervisor)