Tag Archives: water pollution

microplastics

Seafood Industry Australia responds to microplastics in Great Barrier Reef fish

The paper, “Classification of marine microdebris: A review and case study on fish from the Great Barrier Reef, Australia” was published in Scientific Reports by researchers from the Australian Institute of Marine Science.

The paper reveals the diverse and prevalent nature of ingested debris in coral trout from the Great Barrier Reef (GBR) World Heritage Area. Marine debris, including small amounts of microplastics, was found in 95% of the fish collected. CEO of Seafood Industry Australia (SIA), Jane Lovell, responded by saying that “this research is a cause for concern, but ultimately more research needs to be done.”

In the paper, the marine debris ingested by 20 coral trout were examined using methods such as Fourier-Transform Infrared Spectroscopy. The debris was classified into three categories: synthetic, semi-synthetic and naturally-derived.

Synthetics include all microplastics, such as nylon, polyethylene, polypropylene, polystyrene, polyester and polyurethane. Semi-synthetic materials are manufactured synthetically from one or more substances of natural origin (e.g. rayon derived from cellulose) or a composite of both naturally-derived and synthetic materials. Naturally-derived materials include natural fibres derived from plants or animals.

Marine debris was found in 19 of the 20 trout analysed, with a total of 172 individual items collected from the fish. Of these items, 52% were classified as semi-synthetic, 42% as naturally-derived, and 6% as synthetic. These results correlate well with other literature on ingested microdebris in fish. Studies revealed a prevalence of semi-synthetic and naturally-derived fibres, which are often incorrectly reported as microplastics.

The authors point out that in GBR offshore waters, both land-based sources as well as oceanic and shipping sources have been suggested as potential sources for the marine plastic pollution.

The source of textile fibres detected in juvenile coral trout, however, is currently unclear and could be from domestic, land-based and shipping-based sewage discharges. Alternatively, international, unknown sources that deliver fibres to the GBR area through oceanic or atmospheric transport could be the cause.

Ms Lovell says the report “needs to be seen as a call to the community to be really conscious of the amount of plastics they are consuming, how they are consuming it and most importantly how they are disposing of it.”

“People need to take responsibility for their own consumption of plastics and take the steps to make changes, irrespective of plastic-bans and legislative enforcements. Just like the broader community, Australia’s professional fishers care about the health of Australia’s oceans and environment, and we encourage others to do the same.”

The authors note that effects of the ingestion of marine debris on wild fish populations are currently unknown and require further investigation. “We’d like to see more research done looking at what the long-term effect, if any, of ingesting plastics is on spawning and fish mortality,” says Ms Lovell.

The debris was found in the gut of the fish, which is removed prior to human consumption.

– Larissa Fedunik

 

New tools in the fight against fish ferals

They’re known as the rabbits of Queensland’s rivers. Tilapia were introduced into Australia in the 1970s through the aquarium trade, and these African exotics are now one of the country’s most destructive pest fish.

“They’re like little bulldozers in a river,’’ says aquatic ecosystems biologist Dr Dean Gilligan. “They dig around in the bottom of rivers, pull out vegetation, stir up mud and generally trash the habitat for native species. They’re also bullies. They’re extremely aggressive toward native fish – and, unfortunately, can breed up into a very large biomass, just like carp.”

Gilligan is a senior fisheries research scientist with the NSW Department of Primary Industries, and leads the CRC’s inland water pests research program, whose focus is to develop new technologies to detect and better control pest fish.

With researchers at the University of Notre Dame in Illinois, US, scientists from the Queensland Department of Agriculture, Fisheries and Forestry and James Cook University have been working to develop a DNA surveillance technique to detect the presence of tilapia in creeks and other waterways.

The spread of tilapia has so far been confined to Queensland, where their range includes one of the state’s biggest river systems – the Burdekin. Several outbreaks in West Australian rivers near Geraldton were controlled thanks to early detection. Preventing the spread of the fish, particularly to the Murray-Darling Basin, is a key concern of the CRC.

Tilapia can thrive in polluted and degraded waterways, and are fast, prolific breeders. Several were added to an ornamental pond at a hotel golf course in Port Douglas, near Cairns. Two years later, an eradication program removed 16 tonnes of tilapia from the pond.

Gilligan says the DNA surveillance technique being developed by the Invasive Animals CRC will enable fisheries officers to more efficiently detect pest fish, even in low numbers.

“Instead of sending a whole team of people out with a boat, nets and a pile of equipment for several days, we can send one person, with a bucket, to collect around nine to 10 litres of water from a river,’’ Gilligan says.

“They dig around in the bottom of rivers, pull out vegetation, stir up mud and generally trash the habitat for native species. They’re also bullies.”

Dr Dean Gilligan leads the Invasive Animals CRC’s inland water pest program.
Dr Dean Gilligan leads the Invasive Animals CRC’s inland water pest program.

The water is filtered, using fine filter paper, and when filtration is complete, the paper is analysed using a standard polymerase chain reaction laboratory test to detect DNA fragments.

“It’s not instantaneous. It takes a couple of days to filter the water and run the test, but it’s a much faster, more reliable [method] of measuring pest fish incursions in a river than using nets, lines and boats. Once the test result is back, we can run a risk assessment and move on to developing an eradication program.”

The DNA surveillance technique was originally developed in the US to detect carp, which are now among Australia’s most destructive environmental pests. The CRC is also evaluating a naturally occurring virus found overseas as a biological control agent to reduce carp impact. Dr Ken McColl, a veterinary virologist at the CSIRO Australian Animal Health Laboratory in Geelong, is leading the research.

McColl is conducting tests to confirm the findings that this carp herpes virus is effective and that it is safe for release into Australia’s waterways to control carp without affecting humans or native species. If successful, the strategic control program will open up new areas of research.

“We’d see unprecedented massive fish kills of carp in rivers, so we need to look at ways to manage collection and disposal of thousands of dead carp,” says Gilligan. “Do they go to council tips as landfill, or could they be ploughed into paddocks as fertiliser? That’s all part of the challenge of developing an eradication technique.”

– Rosslyn Beeby

www.invasiveanimals.com