May 072014

By Greg Wallis (pseudechis) at YouTube

The Barramundi or Giant Perch (Lates calcarifer) is an iconic fish from the freshwater billabongs, estuaries and coastline of northern Australia. Growing to 180cm and 60kg in size, these fish are a formidable predator.

Hatchling Barramundi are almost entirely males and spend their first year around mangroves and floodplain lagoons before moving further upstream into freshwater. At around 3 — 5 years of age and 60 — 80 cms the fish change sex and become female and move downstream to the tidal river mouths to breed.

Generally speaking it’s not a good idea to swim in natural waterways where Barramundi occur. Because they migrate from upstream freshwater areas down to the mouths of the rivers and back again, if you see Barramundi in a swimming hole it means that there are no substantial barriers downstream impeding their movement up from the coast, which also means Saltwater Crocodiles will have no problems in also accessing the area!

Barramundi are highly prized by fisherman both for their eating and fighting qualities. They are a very important food source for Aboriginal people and are regularly depicted in bark paintings and rock art.

For more information on Barramundi see the Fishes of Australia website…

CAAB Taxon Code: 37310006


May 072014

Media release from AlphaGalileo

Drones and “flying eyes” are making a major advance into the aquaculture industry.
In this experiment, researchers used the

In this experiment, researchers used the “OceanEye” system supplied by Maritime Robotics. The balloon, which is equipped with a remote-controlled camera, can remain airborne and will supply clear aerial images, even in “fresh breeze” conditions. The experiment was carried out at the Rataran facility, operated by SALMAR and ACE.

Is a facility adequately anchored? Are the wet-well vessels in the right place at the right time? Do the net pens have weaknesses which can result in escapes? It’s now possible, with the help of a couple of key strokes and techno assistance from above, literally to obtain an overview of all these issues. Continue reading »

May 032014

The ConversationOriginal story by Tom Rayner, Charles Darwin University and Richard Kingsford at The Conversation

Wetlands and rivers need water – not least in the case of Australia’s biggest river system, the Murray-Darling Basin, which has been the target of an “environmental watering” plan designed to preserve its water levels and quality.
Water management in the Murray-Darling may be inadvertently helping the common carp at the expense of native fish. Photo: Tom Rayner

Water management in the Murray-Darling may be inadvertently helping the common carp at the expense of native fish. Photo: Tom Rayner

But our research shows that, during the 2010-11 floods, measures taken to manage water levels and preserve local wildlife ended up helping alien species, such as the troublesome common carp.

A helping hand for fish

Environmental watering programs are used worldwide to replenish previously degraded catchments. One of the ways to test how well they are working is to look at what happens to native fish. Our evidence suggests that efforts in the Murray-Darling, although on the right track, might need some refinement to ensure we help the right species.

The 2010-11 episode also highlights the difficulty of performing what amounts to “environmental triage” on degraded river systems such as the Murray-Darling, while still ensuring that everything stays in balance. Continue reading »

May 022014

Original story by Daniel Bateman, Cairns Post

A RARE tropical fish never seen in Australian waters has been collected from the depths of the Coral Sea to be sold to an overseas aquarium.
DEEP SEARCH: Cairns Marine has collected a rare fish (pseudanthias Aurulentus, Golden Anthias) from the Coral Sea, believed to be an Australian first. Divers dove to a depth of 60m on the reef to collect the species, pictured at Cairns Marine. Photo: News Limited

DEEP SEARCH: Cairns Marine has collected a rare fish (pseudanthias Aurulentus, Golden Anthias) from the Coral Sea, believed to be an Australian first. Divers dove to a depth of 60m on the reef to collect the species, pictured at Cairns Marine. Photo: News Limited

Far North-based aquarium collectors Cairns Marine discovered a school of golden anthias at a depth of 60m during an expedition last week at Holmes Reef, about 240km east of Cairns.

The colourful fish are typically known from the Central Pacific, extending south of Hawaii.

Pseudanthias aurulentus - Golden Anthias. Photo: News Limited

Pseudanthias aurulentus – Golden Anthias. Photo: News Limited

They are regarded within the aquarium world as the perfect coral reef display fish, however they are difficult to come by in the wild due to their deep-water nature.

Cairns Marine is Australia’s largest supplier of marine life for display, supplying retail outlets, international wholesalers and public aquariums.

It is one of two aquarium companies in Australia that is licensed to collect some species within the Coral Sea.

Cairns Marine’s Fenton Walsh said one of the company’s divers, using a rebreather apparatus, was able to recognise the large school of thousands of golden anthias and act quickly enough to catch about 70 individuals.

“It takes a pretty keen eye. There wouldn’t be too many people who would have spotted it,’’ he said.

“The average person would just say it’s just another pretty fish swimming around.

“It doesn’t look any different to the other ones out on the Reef.”

The company’s sales and logistics manager Julian Baggio said some anthias would be sold in Japan, while others were destined for retailers across Australia.

“We’re also taking some to a large aquarium trade show in Germany later next month,’’ he said.

Apr 202014

Original story by David Lockwood, Sydney Morning Herald

The contentious issue of marine parks and the ambitious efforts by some lobby groups to have the harbour sanctioned as one got me thinking.

Problems remain: Pollution levels in the Parramatta River remain a problem. Photo: Mike Bowers

Problems remain: Pollution levels in the Parramatta River remain a problem. Photo: Mike Bowers

What can we do to ensure our world-famous waterway remains an exemplary estuary brimming with marine life for all to enjoy?

Some whimsical, fanciful marine park utopia is off the mark. Commercial fishing has shutdown for a good reason and there are no fish species in the harbour under threat from angling.

By far the biggest problem is water quality. This isn’t rocket science. You need to ensure a clean source to safeguard the marine environment. If environmentalists spent one tenth of their energies focusing on water quality they might get somewhere.

Take Parramatta River, the very lifeblood of Port Jackson, whose sediments are so polluted that consumption of fish caught west of the Harbour Bridge is dangerous. In Homebush Bay, you are banned from even wetting a line.

Researchers have reportedly discovered that concentrations of copper, zinc and lead from stormwater and past industrial work in Port Jackson were so toxic they have rendered the oysters sterile. This is serious.

Oysters are the canaries in the mine or marine world, and less oysters mean less fish. But they are just the tip of the iceberg when it comes to pollution woes and researchers fear other marine critters are under great stress.

University of NSW Professor Emma Johnston said we need to find ways to lessen the problem of heavy-metal pollution because it is causing ongoing ecological damage. The most heavily contaminated estuaries were Port Jackson, Port Kembla, Botany Bay and the Hunter River.

In fact, some parts of Sydney Harbour have some of the most contaminated sediments in the world. Yet as Professor Johnston lamented, rarely is anything done about it.

Since commercial fishing was banned from the harbour in 2006, we’ve seen nothing concrete to repair poisonous Parramatta River. The problems of heavy metals and dioxins won’t go away on their own.

If everyone with an interest in the waterway banded together and directed their energies and expenditure at a pollution fix, there would surely be something to show for it.

Meantime, the harbour is hardly the pristine environment that green groups would like you to believe. In an oyster shell, we should forget marine parks and clean up our backyard first.

Weather warnings are in place for fishers and boaters this Easter, with large groundswells predicted to continue throughout the long weekend. But around the tidal estuary mouths, you’ll find plenty of healthy fish for the frying.

Kingfish, samson fish and amberjack are on the chew, school jewfish are about the Hawkesbury, while bream, luderick and whiting are milling in big numbers including along the beaches.

Easter is snapper time, with yellowfin tuna making a seasonal appearance down south, and trout get frisky in the Alps in anticipation of their annual spawning run.

Apr 152014

Original story by  Jake Sturmer, ABC News

Researchers in New South Wales have begun a trial to search for the “Achilles heel” of carp.
Carp Etch. Image: DAFF Qld

Carp Etch. Image: DAFF Qld

The introduced species is considered to be one of the world’s most invasive and scientists say they are Australia’s worst aquatic pest.

The project will tag and track carp in the upper Murrumbidgee River, which have played a part in the significant decline of native fish.

Scientists estimate 90 per cent of all native fish have been lost in the river since European settlement.

University of Canberra Associate Professor Mark Lintermans says the fish have had a significant impact on the waterways.

“[They compete] for food, they carry parasites that then spread on to native fish,” he said.

“There’s even a suggestion that they might be hoovering up eggs of native fish as they feed along the bottom.”

The research is being done with the New South Wales Department of Primary Industries and Bush Heritage Australia in its Scottsdale Reserve.

“This project is initially about gathering information – there’s a gap of knowledge of the carp in the upper reaches of the Murrumbidgee,” reserve manager Peter Saunders said.

“So we’re looking to understand what they’re doing, where they’re aggregating, what their populations are and how they’re breeding and where they’re breeding.

“Then [we plan to] expand that project into actually starting to remove them to benefit the native fish which we know are in here in small numbers.”

Local angler and member of the Capital Region Fishing Alliance, Steve Samuels, says a lot has changed since he began fishing in the river in the 1970s.

“There was Murray Cod, Golden Perch, Silver Perch – it was a wonderful place to fish,” he said.

“But today as you see it, the water’s a lot dirtier and carp now dominate as the most prolific fish in the system.”


Apr 152014

Media release by Tom Rickey, Pacific Northwest National Laboratory

Fish-friendly hydropower is the goal of international team
Zhiqun (Daniel) Deng (l) and Rich Brown in the Three Gorges Dam in China.

Zhiqun (Daniel) Deng (l) and Rich Brown in the Three Gorges Dam in China.

Think of the pressure change you feel when an elevator zips you up multiple floors in a tall building. Imagine how you’d feel if that elevator carried you all the way up to the top of Mt. Everest — in the blink of an eye.

That’s similar to what many fish experience when they travel through the turbulent waters near a dam. For some, the change in pressure is simply too big, too fast, and they die or are seriously injured.

In an article in the March issue of the journal Fisheries, ecologists from the Department of Energy’s Pacific Northwest National Laboratory and colleagues from around the world explore ways to protect fish from the phenomenon, known as barotrauma.

Among the findings: Modifying turbines to minimize dramatic shifts in pressure offers an important way to keep fish safe when passing through dams. The research is part of a promising body of work that aims to reduce such injuries by improving turbine designs in dams around the world.

PNNL researchers are working with officials and scientists from Laos, Brazil, and Australia — areas where hydropower is booming — to apply lessons learned from experience in the Pacific Northwest, where salmon is king and water provides about two-thirds of the region’s power. There, billions of dollars have been spent since 1950 to save salmon endangered largely by the environmental impact of hydropower.

Colorized photo of the swim bladder of a smallmouth bass.

Colorized photo of the swim bladder of a smallmouth bass.

“Hydropower is a tremendous resource, often available in areas far from other sources of power, and critical to the future of many people around the globe,” said Richard Brown, a senior research scientist at PNNL and the lead author of the Fisheries paper.

“We want to help minimize the risk to fish while making it possible to bring power to schools, hospitals, and areas that desperately need it,” added Brown.

Harnessing the power of water flowing downhill to spin turbines is the most convenient energy source in many parts of the world, and it’s a clean, renewable source of energy to boot.

In Brazil, several dozen dams are planned along the Amazon, Madeira and Xingu rivers — an area that teems with more than 5,000 species of fish, and where some of the largest hydropower projects in the world are being built. In southeastern Australia, hydropower devices are planned in the area drained by the Murray-Darling river system. And in Southeast Asia, hundreds of dams and smaller hydro structures are planned in the Lower Mekong River Basin.

The authors say the findings from a collaboration that spans four continents improve our understanding of hydropower and will benefit fish around the globe. New results about species in the Mekong or Amazon regions, for instance, can inform fish-friendly practices in those regions of the United States where barotrauma has not been extensively studied.

To ‘Everest’ and back in an instant

Dams vary considerably in the challenges they pose to migrating fish, and the challenges are magnified when a fish must pass through more than one dam or hydro structure. At some, mortality is quite high, while at others, such as along the Columbia River, most fish are able to pass over or through a single dam safely, thanks to extensive measures to keep fish safe. Some fish spill harmlessly over the top, while others pass through pipes or other structures designed to route fish around the dam or steer them clear of the energy-producing turbines.

Researcher John Stephenson observes young salmon in a chamber used to simulate the conditions that fish sometimes experience as they travel through a dam.

Researcher John Stephenson observes young salmon in a chamber used to simulate the conditions that fish sometimes experience as they travel through a dam.

Still, at most dams, the tremendous turbulence of the water can hurt or disorient fish, and the blades of a turbine can strike them. The new study focuses on a third problem, barotrauma — damage that happens at some dams when a fish experiences a large change in pressure.

Depending on its specific path, a fish traveling through a dam can experience an enormous drop in pressure, similar to the change from sea level to the top of Mt. Everest, in an instant. Just as fast, as the waters swirl, the fish suddenly finds itself back at its normal pressure.

Those sudden changes can have a catastrophic effect on fish, most of which are equipped with an organ known as a swim bladder — like a balloon — to maintain buoyancy at a desired depth. When the fish goes deeper and pressures are greater, the swim bladder shrinks; when the fish rises and pressure is reduced, the organ increases in size.

For some fish, the pressure shift means the swim bladder instantly expands four-fold or eight-fold, like an air bag that inflates suddenly. This rapid expansion can result in internal injuries or even death.

Factors at play include the specific path of a fish, the amount of water going through a turbine, the design of the turbine, the depth of water where the fish usually lives, and the physiology of the fish itself.

“To customize a power plant that is the safest for the fish, you must understand the species of fish in that particular river, their physiology, and the depth at which they normally reside, as well as the tremendous forces that the fish can be subjected to,” said Brown.

PNNL scientists have found that trying to keep minimum pressure higher in all areas near the turbine is key for preventing barotrauma. That reduces the amount of pressure change a fish is exposed to and is a crucial component for any turbine that is truly “fish friendly.” Preventing those extremely low pressures also protects a turbine from damage, reducing shutdowns and costly repairs.

Chinook salmon

Chinook salmon

Lower Mekong River Basin

Brown and PNNL colleague Zhiqun (Daniel) Deng have made several trips to work with scientists in Southeast Asia, where dozens of dams are planned along the Mekong River and its tributaries. The Mekong starts out high in Tibet and travels more than 2,700 miles, touching China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. The team estimates more than 1,200 species of fish make their home in the Mekong, including the giant Mekong catfish and the giant freshwater stingray, as well as the endangered Irrawaddy dolphin.

The scientists estimate that the region’s fish account for almost half of the protein in the diet of the people of Laos and nearly 80 percent for the people of Cambodia. Four out of five households in the region rely heavily on fish for food, jobs, or both.

“Many people in Southeast Asia rely on fish both for food and their livelihood; it’s a huge issue, crucial in the lives of many people. Hydropower is also a critical resource in the region,” said Deng, a PNNL chief scientist and an author of the paper.

“Can we reduce the impact of dams on fish, to create a sustainable hydropower system and ensure the food supply and livelihoods of people in these regions? Can others learn from our experiences in the Pacific Northwest? This is why we do research in the laboratory — to make an impact in the real world, on people’s lives,” added Deng.

The same team of scientists just published a paper in the Journal of Renewable and Sustainable Energy, focusing broadly on creating sustainable hydro in the Lower Mekong River Basin. The paper discusses the potential for hydropower sources in the region (30 gigawatts), migratory patterns of its fish, the importance of fish-friendly technology, and further studies needed to understand hydro’s impact on fish of the Mekong.

Authors of the Fisheries paper include scientists from PNNL, the National University of Laos, and the Living Aquatic Resources Research Center in Laos, the Federal University of São João Del-Rei in Brazil, the University of British Columbia; and from Australia, the Port Stephens Fisheries Institute in New South Wales, the Narrandera Fisheries Centre in New South Wales, and Fishway Consulting Services. PNNL’s work in the area has been funded by the U.S. Army Corps of Engineers, DOE’s Office of Energy Efficiency and Renewable Energy, and AusAid, the Australian Agency for International Development.

Reference: Richard S. Brown, Alison H. Colotelo, Brett D. Pflugrath, Craig A. Boys, Lee J. Baumgartner, Z. Daniel Deng, Luiz G.M. Silva, Colin J. Brauner, Martin Mallen-Cooper, Oudom Phonekhampeng, Garry Thorncraft, Douangkham Singhanouvong, Understanding barotrauma in fish passing hydro structures: a global strategy for sustainable development of water resources,Fisheries, March 2014, DOI:10.1080/03632415.2014.883570.

Apr 152014

Original story by Michael Cavanagh, ABC Rural

They could be described as the canaries of the estuaries.

Oysters used to detect contaminants. Researchers using Sydney Rock oysters show the health of NSW waterways varies dramatically.

Oysters used to detect contaminants. Researchers using Sydney Rock oysters show the health of NSW waterways varies dramatically.

Sydney rock oysters – which are not part of commercial operations but selected by researchers – are being used to chart the state of waterways from the Hunter Valley through to the New South Wales/Victorian border.

Results varied from high levels of metals in waters around Wollongong through to a pristine environment around the Clyde River near Bateman’s Bay, on the south coast.

Professor Emma Johnston, from the University of New South Wales, says oysters were ‘significantly stressed’ with damaged cells in the estuaries where there were high levels of metals including copper, lead and zinc.

“These oysters are exposed to all the conditions in the water, just as the canaries were exposed to those in air.

“So if something goes wrong we know that there is a problem in the system, so our oysters are filter feeders.

“So they can filter loads of water every day and if there is a containment in the water, they’ll be exposed to that and they will respond.”

Apr 132014

Original story by , Sydney Morning Herald

High concentrations of metals in Port Jackson, Port Kembla and Botany Bay are having a major impact on marine life, researchers have found.
Shell shock: Professor Emma Johnston and Dr Katelyn Edge. Photo: Brendan Esposito

Shell shock: Professor Emma Johnston and Dr Katelyn Edge. Photo: Brendan Esposito

Toxic levels of copper, zinc and lead from stormwater or due to past industrial dumping are making Sydney rock oysters infertile, University of NSW scientists say.

”We know there are contaminants in the sediments in some estuaries in NSW but we didn’t know what impact they were having on the marine life living in the water until now,” research supervisor Emma Johnston said.

Contaminated oysters found near Five Dock. Photo: Brendan Esposito

Contaminated oysters found near Five Dock. Photo: Brendan Esposito

The study of 10 NSW estuaries, the first of its kind to measure the effect of toxins on marine animals rather than just measure the level of contaminants in the water or sediment, suggests the pollutants might also be harming other species.

”There are hot spots of contamination throughout estuaries in NSW and we need to find ways to ameliorate that problem because it is causing ongoing ecological damage,” Professor Johnston said.

Although oysters were a hardy species and could survive in heavily polluted areas, they accumulated contaminants such as metals in their tissues, which made them an ideal ”bio-monitor” to assess the overall health of a waterway, she said.

As part of the study, marine ecotoxicologist Katelyn Edge deployed bags of oysters at 58 sites in 10 estuaries along the coast.

After three months Dr Edge, who conducted the research as part of her PhD, measured the level of contaminants in the sediment on the estuary floor, in the water column and in the tissue of the oysters.

”Where the concentration of contaminant was high in both the sediment and oysters’ tissue we found really high stress levels in the oysters,” said Dr Edge, who published her findings in the journal Chemosphere.

The most heavily contaminated estuaries were Port Jackson, Port Kembla, Botany Bay and the Hunter River in Newcastle, she said.

The Clyde, Port Hacking, Broken Bay, Karuah River and the Wagonga Inlet were the cleanest waterways.

Professor Johnston said the findings were a counter to arguments against remediating contaminated sites because their results showed metals in the sediments were causing problems for animals living above the estuary floor.

”’Just leave it there, it’ll be fine’ is an argument we have heard.”

In waterways such as Sydney Harbour, ferries and boats were constantly stirring sediments and dragging contaminants into the water column, she said.

”There are some locations in Sydney Harbour that are some of the most contaminated in the world and rarely is anything done about it,” Professor Johnston said.

In laboratory studies Dr Edge found high levels of metals inside the oysters’ tissues would rupture structures inside their cells, affecting the ability to reproduce.

Sydney rock oysters, a native species found along the coast from Queensland to Tasmania and South Australia, should be used as a biomarker during future developments or dredging to assess the impact on marine ecosystems.