Study to examine dolphins’ soundscape

TO understand the underwater worlds dolphins inhabit, Curtin University researchers are looking to examine the noise environment of the Swan River.

The research project aims to build a solid picture of the soundscape of the Indo-Pacific bottlenose dolphins that live in the Swan River by setting up underwater listening stations.

Curtin University's Centre for Marine Science and Technology deputy director Chandra Salgado Kent is managing the research project.

She has been researching dolphins for the past decade.

Dr Salgado Kent said it was important to understand if the sound environment in the Swan River was changing and what potential implications it had on dolphins’ ability to communicate.

She said poor visibility in the river meant dolphins had developed an advanced ability to use sound to navigate their environment.

"Dolphins have evolved to depend on sound heavily for navigation, communication, avoiding predators, and for locating prey," Dr Salgado Kent said.

"The acoustic environment in which they live can dictate how well they are able to use sound for these purposes.

"Every location within the river has different noise sources, including a range of man-made noises associated with our own use of the river."

Dr Salgado Kent said little was known about the sound environments that dolphins live in, and the impact they could have on their livelihood.

Sound stations will be used in the river to uncover the hidden information.

"By better understanding if there are any limitations in the ability of dolphins to communicate and undertake their daily activities in a relatively noisy environment, we can begin to improve how we conduct our own noise generating activities around dolphins," she said.

Murdoch University’s Delphine Chabanne has been researching dolphins in the Swan Canning riverpark for four years.

The PhD candidate said, based on sighting frequency, the riverpark was home to about 23 adult/juvenile dolphins and six calves.

The last calf was born in late January or early February this year.

Ms Chabanne said the Perth dolphin community was doing well, but over the past four years, four calves had

died.

She also said the small size of the dolphin community made the mammals vulnerable.

"Every day, dolphins in the Swan Canning riverpark face challenges such as noise disturbance, boat strikes, entanglement with fishing lines or other rubbish," she said.

"Summer-autumn seasons are generally described as the critical season because of the increase of recreational

activities in the Swan Canning riverpark.

"Also, this is the time of the year when dolphins give birth. Calves are naturally extremely vulnerable with a high mortality rate (30 to 50 per cent)."

A crowd-funding project has been set-up to raise funds needed to complete the research.

Contributions will go towards analysing data, installing new listening stations and servicing the listening stations.

Contributions can be made at https://curtin.hubbub.net/p/dolphins/.

Curtin is hoping to crowd-fund $7500.