In a new study published in Scientific Reports, researchers from the UK, US and France observed bluestreak cleaner wrasse at 24 cleaning stations and discovered that the noise from motorboats affected the behavior of both the cleaners and their ‘clients’.

At seventeen of the cleaning stations, in the presence of motorboat noise, the cleaner fish were more likely to nibble at their client’s protective mucous layer rather than clean off parasites.

According to lead author Dr Sophie Nedelec from the University of Exeter, “Cleaners were biting their clients during boat noise and, instead of leaving or retaliating, the clients let the process go on for longer than normal.”

She added that such behavior suggested cognitive impairment in either one or both parties.

“One explanation is the clients are distracted by boat noise and cleaners are taking advantage of this to cheat on their clients,” said Dr Suzanne Mills, of EPHE and CRIOBE.

Such a change in behavior may impact on the resilience of coral reef. Without the effective removal of parasites by cleaner fishes, the coral reef fish health, abundance and diversity may be adversely affected.

The study, which involved researchers from the US, UK and France, highlights the need to control man-made noise in protected habitats. “We are now considering acoustic quiet zones and corridors, and exploring how engine and propeller development can reduce the impact of this globally prevalent pollutant,” said Dr Steve Simpson, from the University of Exeter.