Posts

Eco-design and pre-seeding among options to encourage healthy port marine life

Pre-seeding new port structures to encourage the colonisation of native species is one of the mitigation measures against invasive marine plants and animals, outlined in a new report prepared for the WAMSI Westport Marine Science Program.

The literature review by Curtin University School of Molecular and Life Sciences Adjunct Professor Fred Wells lists many of the invasive marine species that have been recorded in waters around Perth and mitigation measures that could be used during any port construction.

Pre-seeding works by attaching local, fast-growing species to a new structure. The common mussel is one option identified in the report.

Professor Wells said invasive marine species were a worldwide problem and shipping was the most common way they spread to coastal areas. Ninety-eight percent of trade in and out of Australia is on vessels.

“Invasive marine species are concentrated on artificial surfaces and eco-engineering is a new field that attempts to encourage biodiversity and prevent potential marine pests taking hold,” Professor Wells said.

“The risk of introducing new species is greatest during construction but experience during the construction boom in the Pilbara demonstrated the issue is manageable.”

Professor Wells said eco-design was a new and evolving field that could help improve the biodiversity of the marine community that develops underwater, while minimising the risk of invasive species.

“Current design procedures tend to create uniform habitats, such as seawalls with smooth vertical faces. The lack of habitat diversity reduces the biodiversity of the marine community that develops on the structure. “

“Increasing the habitat diversity of new immersed structures and pre-seeding them with native species appear to be the most promising ways for mitigating against species that can cause ecological harm and prove expensive.”

Professor Wells said the biggest threats from invasive species to marine ecosystems were introducing disease, displacing native species, changing the ecology of native communities, clogging pipes and damaging other critical infrastructure.

The report, which was done to understand potential risks, is a literature review of invasive marine species from Cottesloe to Cockburn Sound, including waters around Fremantle and the Swan River.

A comprehensive survey more than a decade ago recorded 60 introduced marine species living in WA waters. Three were on the national marine pest list. Four additional marine pests were subsequently recorded in WA.

“Fortunately, most introduced marine species are apparently innocuous, causing no known adverse effects and we know only a small portion become pests,” Professor Wells said.

 

 

Underwater symphony of noisy shrimp and whistling dolphins

Waves crashing, boats motoring and seabirds squawking are what we typically hear at the beach.

But a WAMSI research team at Cockburn Sound is listening to the soundscape underwater and recording everything from the ‘popping’ noise of tiny snapping shrimp to fish sounds and whistling dolphins.

Vessels travelling across the water are also picked up.

Dr Iain Parnum, from Curtin University’s Centre for Marine Science and Technology, is part of a research team that has been using underwater microphones, known as hydrophones, which are linked to a recording device and lowered into the water.

“We put them in the water and leave them on the seafloor for several months at a time, so we have this continual data,” Dr Parnum said.

“We are trying to understand the underwater soundscape of Cockburn Sound.”

“We want to characterise different sounds that can be heard, how loud they are and how that soundscape changes through the year.”

He said it was also useful for locating different species and information will be shared with other researchers involved in the WAMSI Westport Marine Science Program.

“Probably in coastal areas like this, one of the main sounds is anthropogenic or human caused.

“We are monitoring places where they have typically been finding dolphins but also areas where they haven’t.  We want to know what the overall sound levels in those areas are, if they are overwhelming and making it difficult for dolphins to communicate.”

“Everyone sees dolphins and it’s always nice to see them, but you also hear them chatting away underwater.

“We need to understand what the baseline sounds in the Sound are.”

The team is yet to record mulloway, but Dr Parnum said they’re a fish that has a distinctive sound.

“Sometimes if there’s enough of them, they like to gather together to do choruses particularly after sunset.”

Man with recording equipment on boat.

Research team member Malcolm Perry works on underwater sound recording equipment.

“That is something we have seen in other sites,” Dr Parnum said.

Other WAMSI Westport Marine Science Program scientists are doing related research on the hearing physiology of animals in the area including little penguins, and the behavioural response of fishes to underwater noise.