Is human noise pollution affecting our sharks?

August 6, 2015 by Lucille Chapuis, Science Network WA
Is human noise pollution affecting our sharks?
Some sharks are migratory and can potentially leave a disturbed area, for example great whites (Carcharodon carcharias), tigers (Galeocerdo cuvier) and whale sharks. Credit: iStock

Human made noise, also called anthropogenic noise, is rising in many environments due to the increase in transportation and the exploration for and exploitation of energy sources.

North Western Australia, in particular as the most active area of the country in terms of oil and gas exploration and coastal construction activities, is filling WA's coastline with added .

In the extreme, anthropogenic noise can destroy the vulnerable sensory tissues, in the and the lateral line systems of fishes.

This may ultimately lead to death if the animals lose their ability to hear or detect hydrodynamic changes.

Noise can also be a source of acute or chronic stress, which may affect behavioural and sensory functions.

Besides, a loud sound can mask important biological sounds, essential to marine organisms in communication, finding prey and mates and detecting predators.

More than 100 species of sharks and rays live in WA waters, ranging from the tiny pygmy shark (Euprotomicrus bispinatus) to the iconic whale shark (Rhincodon typus), the world's biggest fish.

Sharks, like bony fishes, possess an inner ear and a lateral line, which are sensitive to underwater vibrations and sounds.

Is human noise pollution affecting our sharks?
Brown banded bamboo shark. Credit: Paul Ricketts/UWA

Compared to marine mammals, sharks have a very narrow hearing range but are known to be particularly sensitive to very low frequencies.

This hearing range overlaps with most of the anthropogenic sound produced by seismic airgun arrays, dredging, pile driving and shipping.

Some sharks are migratory and can potentially leave a disturbed area, for example great whites (Carcharodon carcharias), tigers (Galeocerdo cuvier) and .

However most of the species, such as wobbegong (Orectolobidae), bamboo (Hemiscylliidae) and Port Jackson sharks (Heterodontus portusjacksoni), stay in a single location or patch of reef or change habitats only when they reach a critical part of their lifecycle like most reef sharks do.

Sound pollution represents a particular threat for those sedentary sharks, as they would typically not leave the area during a high intensity sound event.

In an effort to fill these vital knowledge gaps, the Neuroecology Group which is part of the UWA Oceans Institute and School of Animal Biology is studying the effects of sounds on sharks.

Our first strategy is to assess their sensitivity to sound such as what frequencies and intensities the different species react to, with electrophysiological techniques in the laboratory.

Assessing the hearing sensitivity of a Port Jackson shark in the lab. Credit: Paul Ricketts/UWA

We will then partner with industry to assess and characterise the different anthropogenic sounds that are 'ensonifying' our waters.

We can then assess the potential overlap, comparing the ambient soundscape with the auditory abilities of local shark species and identify any threats of local sound sources to the local shark populations.

Finally, and most importantly the behaviour of wild animals and their responses to different anthropogenic noise needs to be observed and examined to establish any short- and long-term effects.

It is a big challenge, as we are examining wild animal movement in their natural habitat and needing to observe and quantify their responses before, during and for an extended period after exposure to particular sounds.

However, at this stage, the specific regulation on anthropogenic noise in Australia covers only a few species of marine mammals.

We feel there is a dire need and a responsibility to fill a large knowledge gap, to inform management practises and policy and broaden the regulatory framework to include the effects of noise pollution on a wider range of marine species, including and their relatives.

Explore further: Tracking project reveals roaming tiger sharks

Related Stories

Tracking project reveals roaming tiger sharks

July 31, 2015

THE sight of a shark's dorsal fin sticking out of the water usually strikes fear into the hearts of swimmers but for a group of WA researchers every time a tagged tiger shark's (Galeocerdo cuvier) dorsal fin stuck out of ...

Ear to the ground on shark sense

July 7, 2014

Research into how sharks hear is set to become the latest tactic to better understand and help prevent fatal shark attacks in Australian waters.

Shark deterrent research reveals interesting results

June 17, 2015

Shark researchers from the Neuroecology Group at The University of Western Australia have released the results of their WA State Government-funded research into the effectiveness of a range of novel and commercial shark deterrents.

Recommended for you

Scientists ID another possible threat to orcas: pink salmon

January 19, 2019

Over the years, scientists have identified dams, pollution and vessel noise as causes of the troubling decline of the Pacific Northwest's resident killer whales. Now, they may have found a new and more surprising culprit: ...

Researchers come face to face with huge great white shark

January 18, 2019

Two shark researchers who came face to face with what could be one of the largest great whites ever recorded are using their encounter as an opportunity to push for legislation that would protect sharks in Hawaii.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Aug 06, 2015
OUR sharks?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.