Manmade noise pollution ‘threatening’ marine life

MANMADE noise pollution from ships, underwater explosions and offshore construction could be damaging marine life’s hearing and impacting on the vital fishing industry by interfering with migration and breeding patterns.

Speakers at a week-long international conference have warned that despite marine industries providing significant benefits to local economies, the potential damage caused to marine habitats is risking the safety of local sea life.

On the first day of the conference on the effects of noise on aquatic life, at the Clarion Hotel in Cork city, 250 of the world’s leading marine experts said manmade acts may be inadvertently making diving birds go deaf, interfering with fish mating and migration, and causing increasing discomfort to sea life.

The phenomenon was first discussed in Denmark in 2007. Giving the conference’s keynote address, marine life expert Dr Brandon L Southall of the University of California said that, due to the relatively new nature of the research, most evidence on how sea life is being affected by man-made noise was preliminary.

However, he said a recent study by the US Navy marine mammal programme found significant disturbances in tracked animals, including 30 dolphins and 15 sea lions, in areas where total ship traffic is between 100 and 350 tonnes a year.

Dr Southall said while underwater noise levels always existed, the reason for the damage to marine life appeared to be caused by an issue known as “temporary threshold shift” – involving sudden unnatural changes in sound levels.

These are mainly caused by ships, oil drills and other man-made objects.

“It is known that very intense sounds may cause tissue damage or impair hearing,” a spokesperson for the conference said. “It may affect the abilities of animals to find one another.. Sound can disrupt behaviour, affect migrations, interfere with mating, interrupt foraging and feeding or simply cause discomfort.”