Tag Archives: marine protected area

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

 

Data dungeons and dragons

Unearthed from the dungeon-like depths of a government building in Hobart, photographic data from aerial surveys is helping to protect the underwater forest home of Tasmania’s dragons. This dragons’ tale is a data reuse success story set against the threat of a warming world.

Giant kelp (Mycocystis pyrifera) grows in magnificent undersea forests, where it thrives in nutrient-rich, cool waters. Kelp forests can be 30 m high and reach the sea surface to sunbake as a floating canopy 40 m across, clearly visible from the air. Giant kelp is the foundation species for its ecological community, providing habitat to weedy sea dragons, big-bellied seahorses, abalone, sponges, corals and myriad other marine species.

These richly biodiverse habitats were thought to be in decline off Tasmania’s east coast but actual data was lacking. Professor Craig Johnson and Dr Piers Dunstan, researchers from the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), found the raw data they needed in archives of aerial survey photos going back to the 1940s. It was then that state governments began using ex-WW2 aircraft and photographic reconnaissance equipment to map coastlines, mostly for planning.

Fellow IMAS researcher Dr Neville Barrett used the same imagery in the late 1990s to undertake the first seabed habitat mapping of Tasmanian waters for marine protected area planning. “It’s classic data reuse. Those aerial surveys were done to map Tasmanian land-based features but we found we could also use the survey photos to study marine habitat,” Barrett said. “Craig and Piers dug up all the aerial photos of the east coast they could find and estimated the percentage of kelp cover in every bay, year by year. They identified a 90% decline in kelp cover between 1945 and 2000.”


Warmer oceans

Why the decline? Climate change is thought to be the main culprit. Oceanographic shifts first seen off Tasmania’s east coast in the 1970s coincided with IMAS’ observations of reduced kelp forests. During the period studied, noticeable strengthening of the East Australian Current created warmer ocean temperatures and reduced nutrient load, conditions which are unfavourable to kelp growth.

Kelp forests are among the most dynamic and productive ecosystems on Earth, yet are unknown to many Australians. Most people could name iconic terrestrial forests like the Daintree in Queensland but would struggle to name a comparable marine equivalent. In 2012, thanks to the work of the IMAS researchers and others, the giant kelp marine forests of southeast Australia became the first marine ecological community to be protected with an endangered listing under Australia’s national environmental laws.

New types of data, including image data from robotic submersibles (autonomous underwater vehicles or AUVs) and satellite data from advanced sensors, are aiding in conserving and managing marine environments. For example, a recent University of Tasmania project measured kelp beds from hyperspectral satellite data exploiting the species’ unique spectral signature.

Studies on restoring kelp communities are underway and, in a twist to the dragons’ tale, the original archive of irreplaceable aerial photos that helped protect their home has now been digitised. The data is now reusable by researchers anywhere.

“Wonderful outcomes like this become more and more possible every year as ANDS and other organisations enable access to more data and share it more readily,” said Barrett.

But, in the end, if we’re to preserve these iconic forests, we need to tackle the root cause, which is the changing ocean conditions. How the forests will ultimately fare in this warming world is a tale whose next chapter is yet to be written.

Story provided by Refraction Media

Originally published in Share, the newsletter magazine of the Australian National Data Service (ANDS).