Fishing line and plastic endangering young dolphins

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A leading Perth dolphin researcher is urging fishers to be extra vigilant with the proper disposal of fishing lines and hooks after seeing several of the marine mammals in Cockburn Sound caught up in discarded line.

Dr Delphine Chabanne, from Murdoch University’s Harry Butler Institute, said she had seen two young bottlenose dolphins within about eight months that had line wrapped tightly around their bodies. Others had been seen caught in line in previous years.

“We want people to understand the harm fishing line and other pollutants cause to marine animals, including dolphins,” Dr Chabanne said.

“Many of the animals recorded with fishing gear entanglement are calves or juveniles and as they grow the lines dig into their skin.“

Dr Chabanne, who is also researching dolphin behaviour as part of the Western Australian Marine Science Institution Westport Marine Science Program, said she feared what researchers saw from boats was the tip of the iceberg.

“More individuals may have injuries from fishing line gear that’s not always visible to us.  As an example, we don’t always get to see the pectorals and tail fin, or fluke, of individuals which makes it difficult to evaluate the full extent of fishing gear impact on dolphins.”

Dr Chabanne said the risk of fishing lines to the animal varied but it could result in death.

“There are some dolphins that manage to get rid of the line by themselves with minimal harm to their bodies but for others, the injuries are too serious and they die, which can be a slow process.”

Some dolphins had been euthanised when their injuries were considered too serious.

Dr Chabanne said line wasn’t the only danger to the animals.

“I have seen a dolphin with a plastic bag around its dorsal fin. If this was to become stuck around its blowhole it would suffocate,” Dr Chabanne said. “Plastic too is a problem when it breaks up into microplastics which are ingested by fish, the main diet of dolphins.”

Studying the elusive syngnathids of the Sound

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Dozens of Perth divers and keen underwater photographers are helping research into the seahorses and pipefishes of Cockburn Sound and Owen Anchorage as part of a project which will also see water-borne DNA tested for evidence of the beautiful but elusive animals.

The project forms part of the WAMSI Westport Marine Science Program and Dr Glenn Moore, the Curator of Fishes at Western Australian Museum, is leading a research team looking into the diversity and distribution of syngnathids, a family of highly specialized and often cryptic fishes that also includes seadragons.

The fish have national protection under the Environmental Protection and Biodiversity Conservation Act of 1999.

“They are one of the most challenging groups of fish to survey,” Dr Moore said.

“We can’t run fine nets over the reef because they get caught up and the fish are difficult to spot diving, so we are using multiple methods including looking at historical records.”

“We are using as many data sources as we can to try and compile as much information as possible about the syngnathids in the Sound.”

Dr Moore said citizen scientists had so far uploaded more than 1,000 images to an online portal along with the location where the fish were spotted.

He said one limitation of citizen scientists was they tended to head towards common dive areas where seahorses were well known but the information was still valuable.

Environmental DNA testing will also start soon on water collected from Cockburn Sound to add to information about their distribution.

“We have done some water sampling and we will do eDNA work in the next few months.

“We have frozen water samples and these will be analysed at a specialist laboratory at Curtin University.

“We are hoping we can start to build a picture of their distribution and habitat preferences,” Dr Moore said.

He said part of the eDNA work involved building a DNA library.

“You need to have something to match the eDNA to when we are doing the analyses.

“We need to get DNA from specimens we are looking for and that is a challenge because we don’t get to collect all the species we know are there.”

Dr Moore said most syngnathids lived in shallow coastal waters and were especially reliant on habitats well represented in Cockburn Sound, including seagrass, filter-feeder communities, shallow detritus, reefs and artificial structures.

He said the distribution, habitat preferences and abundance, particularly of seahorses and pipefish, wasn’t well known but the research aimed to find out more with the aim of improving their protection.

Photos: Western Australian Museum

Big pods and ‘fearless mums’ among the dolphins of Kwinana Shelf

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A dolphin with a distinctive white flash and a female bearing the scars of a shark bite, likely suffered while protecting her calf, were among about 120 individual dolphins recorded by researchers in the Kwinana Shelf area last year.

Dr Delphine Chabanne, from Murdoch University’s Harry Butler Institute, is leading the project which forms part of the WAMSI Westport Marine Science Program and involves monitoring dolphin distribution from Woodman Point to James Point within Cockburn Sound.

The dolphins that were recorded included 24 calves under two years of age.

The research team did the surveys from a boat travelling along parallel lines, 500 metres apart.

Dr Chabanne said 55 percent of the non-calf dolphins were re-identified from the last survey work between 2011 and 2015, indicating there are long term dolphin residents in Cockburn Sound.

“The long-term connection with other resident communities is also supported with four of the Swan Canning estuary resident male dolphins observed interacting with dolphins in Cockburn Sound,” Dr Chabanne said.

The team photographed the animals, noted their GPS coordinates and recorded water temperature and depth at the locations.

“One of the challenges was to make sure we have photographs for all dolphins when the groups are large,” Dr Chabanne said.

“We were seeing 15 to 35 dolphins in a pod, sometimes breaking into smaller groups then re-joining before breaking again into smaller groups all in less than 30 minutes. This fission-fusion behaviour is typical in bottlenose dolphins.”

Dolphin with shark bite mark on fin. Photo: Delphine Chabanne

Dr Chabanne said ‘Tippy’, one of the adult females, had a damaged dorsal fin from a shark bite.

“The females are more vulnerable to being attacked because the sharks will often target the calves and the mothers will work very hard to protect them.”

The first time ‘Tippy’ was recorded with fresh shark bites, her calf was only two months old. Two weeks later, ‘Tippy’ had suffered from further shark bites. The next time she was seen, unfortunately, her calf had disappeared.

Predation by other animals is not the only risk. Dr Chabanne said researchers spotted at least two calves with fishing lines around their bodies or pectorals.

Dr Chabanne said ’Tippy’, was first recorded in the early 1990s and is believed to be close to 40 years old. In fact, several individual dolphins observed in Cockburn Sound during the last year are between 30 and 40 years old.

Another female called ‘Jinx’, with a distinctive white mark on her back, is believed to be close to 30 years old and gave birth to a new calf this year.

Dr Chabanne said the average life expectancy for a female in the wild was 40 years, with males often not surviving beyond 35 because of fighting and riskier behaviour such as venturing into less protected areas.

The researchers are looking at where the dolphins in the Kwinana Shelf area spend most of their time during the year and working out why they are in certain areas.

Dr Chabanne said data was collected over four seasons to see how dolphins responded to changes in the environment.

Underwater symphony of noisy shrimp and whistling dolphins

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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.

Dolphin dreams a reality for WAMSI scientist

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On International Women’s Day, March 8, WAMSI Science Coordinator Dr Kelly Waples reflects on her career

As a young girl in beachside California, Kelly Waples dreamt of being a dolphin trainer from the first time she visited a marine aquarium. Her interest soon shifted from spectacle to science but a passion for the marine mammals remained.

Dr Waples, now a Principal Scientist for Department of Biodiversity, Conservation and Attractions and a Science Coordinator for Western Australian Marine Science Institution (WAMSI), ultimately did her doctoral research on rehabilitating and releasing captive dolphins.

“I was always interested in dolphin behaviour, but as I spent more time in the field, I became interested in applying what we learn about these animals to conservation questions,” Dr Waples said.

“The opportunity to work on a dolphin release came up and I jumped at the chance to return to Australia and participate in what was, at the time, a groundbreaking project.”

She described finishing her PhD and moving to Australia as a time when her career hit a crossroads.

“It became clear to me that to pursue a career in marine mammal field biology was not going to be easy or provide much in the way of job security.”

A move to wildlife conservation as a coordinator of wildlife management in New South Wales was ultimately a rewarding opportunity.

“I was responsible for coordinating and advising on a range of issues from nuisance flying foxes and possums to whale strandings and oil spills,” Dr Waples said.

“I was lucky to again have a career change when I returned to Perth and joined the Marine Science Program at DBCA.

“I have more of a science coordination role at WAMSI and have the opportunity to interact with a wide range of scientists from various disciplines to participate in research supporting conservation decisions and to advise on a number of marine mammal issues.”

In her role at WAMSI, Dr Waples is back working on a project involving her first research ‘love’- marine mammals.

“I’ve really enjoyed this last year with the opportunity, through the WAMSI Westport Marine Science Program, to be out in the field in our own backyard here in Perth learning more about the endangered Australian sea lions.”

“I’m learning new skills and working with a wide range of fantastic scientists, veterinarians and marine staff.”

Reflecting on International Women’s Day, Dr Waples said while most of her early mentors and colleagues were male scientists it had been heartening to see that change over time with many amazing and dedicated female scientists joining the ranks.

“I hope that I have done my part (improving the gender balance) by championing young female scientists where I can and giving them the advice and support to choose their paths well.”