Coast KZN

27 Oct 2018

Offshore surveys could devastate marine food source

Tamlyn Jolly (Zululand Observer) Picture: A seismic survey vessel (Photo:

New studies reveal an alarming effect seismic surveys could have on the ocean’s ‘forgotten ones’

Seismic surveys could spell disaster for the ocean’s microscopic animals at the bottom of the food chain, essentially jeopardising ocean life as a whole.

These were the findings of a new study looking into the effects of powerful sound waves created during offshore surveys for oil and gas.

Seismic surveys blast compressed air to produce pulses of sound that can probe the sea floor thousands of metres down, for natural resources.

Image depicting how seismic surveys are carried out SOURCE: 

The study found that, at 220 – 250 decibels, the pulses produced from these blasts are louder than a Saturn V rocket during launch.

Zooplankton, the collective name for the ocean’s microscopic animals, are thought to be most at risk from seismic surveys.

Damage to these creatures could have a devastating effect on the ocean’s top predators and commercially important fish species which depend on Zooplankton for food.

Scientists have known for decades that whales and other marine mammals that use sound to communicate change their behaviour in response to such noise, but this is the first study revealing the harm to Zooplankton.

‘It could be that our focus has kind of been blinkered because it’s been on whales,’ said lead author Jayson Semmens, a marine biologist at the University of Tasmania in Hobart, Australia. ‘Invertebrates are the forgotten ones.’