Investigations are underway into the cause of a large fish kill at a central Queensland waterway.
Council probes Clermont lagoon fish kill. More than 1,500 fish have washed up dead at Hood's Lagoon in Clermont in central Queensland since Monday. Photo: Stephanie Keyte
More than 1,500 fish have washed up dead at Hood's Lagoon in Clermont since yesterday morning.
Isaac council acting chief executive Scott Riley says the issue is not related to water quality problems at Dysart.
He says council workers have observed fish gasping for air.
"I think the issue we are dealing with in Clermont is more of a routine maintenance type of issue that's linked to the normal maintenance of the town's supply system, whereas in Dysart, it's been a water quality issue in terms of the defined supply via the pipeline," he said.
He says it could be linked to stormwater contamination.
"We have observed fish that have been gasping for air which indicates there may be low levels of oxygen ... in the water," he said.
"It appears that there may have been an event where low oxygen levels were caused when we installed essentially some backwashing of stormwater lines."
A hybrid system using Flowforms in a treatment pond, in Norway. Photo: Aalang/WikiMedia Commons
The construction of wetlands has an important role to play in strategies to offset the loss of natural wetlands and treat wastewater. Typically, the effectiveness of constructed wetlands is assessed by comparing their levels of species abundance and diversity with those in natural wetlands. However, these structural indicators aren’t necessarily good measures of ecosystem function. In a study of riparian locations on the Ebro River in Spain, net ecosystem production (NEP, the balance between primary production and community respiration) was measured in matched sets of natural and constructed wetlands. Analysis revealed that water column NEP was significantly higher in natural than constructed wetlands. In the natural wetlands, NEP was highest in unvegetated habitats,while in the constructed wetlands NEP tended to be greatest in habitats dominated by submerged plants, particularly the branching alga Chara. Because previous work showed that invertebrate communities recovered rapidly in the same constructed wetlands, the new results suggested that ecosystem function recovered more slowly than ecosystem structure. Therefore, useful insights may be gained by including ecosystem function in the design and evaluation of new wetlands.
Every surfer who pulled up at a beach to check the waves has known the universal disappointment that goes with being told ''you should have been here yesterday''.
The phrase became part of beach lingo in the first surf film to cross over into the mainstream, Bruce Brown's The Endless Summer.
Not what they used to be: Richie Vaculik at Maroubra. Photo: Dean Sewell
Fifty years later, ''you should have been here last century'' looks like being the new reality for surfers who chase storm surf.
Latest findings by the Bureau of Meteorology predict big surf will increasingly become a thing of the past. Andrew Dowdy, lead author of a study for the bureau's Centre for Australian Weather and Climate Research, said fewer large waves were projected for eastern Australia because storms were not going to be as hostile. But while bad news for big wave riders, there was a bright side: the wave research was carried out partly due to increased concern with coastal erosion and rising sea levels.
''Our study was focused on storm waves. We found increasing greenhouse gases will likely reduce the number of storm waves for central east coast of Australia for the end of this century,'' Dr Dowdy said.
The bureau researchers took readings from wave observation buoys located six to 12 kilometres offshore from Coffs Harbour to Eden on the south coast and collated it with data and conditions high in the atmosphere about five kilometres above sea level.
''It was a new method that provided a really good indication of the risk of large waves occurring,'' Dr Dowdy said. ''We used climate models that could represent those conditions … that [showed] us how that might change in the future. They proved more consistent than previous studies, as well as allowing the influence of greenhouse gases to be clearly shown.
''It all comes down to how much greenhouse gases are in the atmosphere. We had one scenario where greenhouse gases continue to rise towards the end of the century, and another where greenhouse gas emissions stabilised. For a higher emission scenario, we can expect a 40 per cent reduction in storm events. If emissions were stabilised, we can expect 25 per cent fewer storms in the region.''
Having endured the worst year for quality surf in 60 years, surfers living along the NSW coast, but especially around Sydney, are under little illusion that something has stopped sending surf onto their beaches, points and reefs.
Maroubra surfer Richie Vaculik said the past year had been the worst for surf in years. ''You look back [to] when you were a little kid and seem to think there was always big surf, but last winter hardly any of the big wave spots - Ours [Cape Solander], Fairy Bower [Manly], the bombies around Queenscliff and Ulladulla - fired at all,'' he said.
Which aquatic species are the most vulnerable to the impacts of climate change? In theory, traits such as physiological tolerance, life history attributes, dispersal abilities and dietary and habitat requirements could be useful indicators of the vulnerability of a species to climate warming, but this possibility needs to be tested for different types of organisms. One such analysis focussed on the freshwater fish of the Murray-Darling river system in Australia, and drew on monitoring data for 39 species, plus data on 14 biological traits for the same species compiled from the literature. Of those traits, 11 showed a significant relationship with changes in species abundance observed in 2004-2010 during a period of extended drought. Trait-based rankings of drought vulnerability also agreed well with species vulnerability assessments from previous studies. The most vulnerable fish species had relatively low heat tolerance and low minimum spawning temperatures. They tended to be small-bodied species (e.g. galaxiids, pygmy perches) that feed on invertebrates, which suggested that omnivores that consume more detritus and plant material have more success in finding food during drought. Vulnerable species also tended to mature early and have a short life-span, an extended spawning season and low fecundity. These are normally considered to be “opportunistic” features typical of species adapted to unpredictable environments, but it seems that that this type of opportunism doesn’t extend to coping with long, multi-year droughts. In prolonged droughts, larger species with delayed maturation are better equipped to survive and breed later. Vulnerability rankings based on a range of traits can help to identify species at risk and prioritise conservation actions.
Reference: Chessman, B. 2013. Identifying species at risk from climate change: traits predict the drought vulnerability of freshwater fishes. Biological Conservation 160, 40–49.
The space rock that smashed into Earth 65 million years ago, famously wiping out the dinosaurs, unleashed acid rain that turned the ocean surface into a witches' brew, researchers said on Sunday.
An artist's impression of the recently identified Torvosaurus gurneyi dinosaur. Photo: Reuters
Delving into the riddle of Earth's last mass extinction, Japanese scientists said the impact instantly vapourised sulphur-rich rock, creating a vast cloud of sulphur trioxide (SO3) gas.
This mixed with water vapour to create sulphuric acid rain, which would have fallen to the planet's surface within days, acidifying the surface levels of the ocean and killing life therein.
Those species that were able to survive beneath this lethal layer eventually inherited the seas, according to the study which did not delve into the effects on land animals.
"Concentrated sulphuric acid rains and intense ocean acidification by SO3-rich impact vapours resulted in severe damage to the global ecosystem and were probably responsible for the extinction of many species," the study said.
The great smashup is known as the Cretaceous-Tertiary extinction.
It occurred when an object, believed to be an asteroid some 10 kilometres wide, whacked into the Yucatan peninsula in modern-day Mexico.
It left a crater 180 kilometres wide, ignited a firestorm and kicked up a storm of dust that was driven around the world on high winds, according to the mainstream scenario.
Between 60 and 80 per cent of species on Earth were wiped out, according to fossil surveys.
Large species suffered especially: dinosaurs which had roamed the land for some 165 million years, were replaced as the terrestrial kings by mammals.
Extinction riddle
Much speculation has been devoted to precisely how the mass die-out happened.
A common theory is that a "nuclear winter" occurred - the dust pall prevented sunlight reaching the surface, causing vegetation to shrivel and die, and dooming the species that depended on them.
Another, fiercely debated, idea adds acid rain to the mix.
Critics say the collision was far likelier to have released sulphur dioxide (SO2) than SO3, the culprit chemical in acid rain. And, they argue, it would have lingered in the stratosphere rather than fallen back to Earth.
Seeking answers, a team led by Sohsuke Ohno of the Planetary Exploration Research Centre in Chiba set up a special lab rig to replicate — on a tiny scale —what happened that fateful day.
They used a laser beam to vapourise a strand of plastic, which released a high-speed blast of plasma and caused a tiny piece of foil, made of the heavy metal tantalum, to smash into a sample of rock.
The heavy foil fragment replicated on a miniscule scale the mass of the asteroid, while the rock was of a similar makeup as the surface where the asteroid struck.
The team caused collisions ranging from 13 to 25 km per second (47,000-90,000 km per hour), and analysed the gas that was released.
The research, reported in the journal Nature Geoscience, showed that SO3 was by far the dominant molecule, not SO2.
The team also carried out a computer simulation of larger silicate particles that would have been ejected by the impact, and found they too played a part.
The articles rapidly bound with the poisonous vapour to become sulphur acid "aerosols" that fell to the surface.
Heavily acidic waters would explain the overwhelming extinction among surface species of plankton called foraminifera.
Foraminifera are single-celled creatures protected by a calcium carbonate shell, which dissolves in acidic water.
The "acid rain" scenario also helps explain other extinction riddles, including why there was a surge in the number of ferns species after the impact. Ferns love acidic, water-logged conditions such as those described in the study.
A cyclone and potential cyclone are expected to bring heavy rain to north Queensland and the Gulf country in coming days.
Tropical Cyclone Gillian forecast track map, issued at 7:56am AEST March 9, 2014. Image: Bureau of Meteorology
Tropical Cyclone Gillian is a category one system, 255 kilometres west-south-west of Thursday Island and is expected to intensify as it moves south along the Gulf of Carpentaria.
Gale-force winds developed between Cape Keerweer and Cape York throughout the day, and could possibly extend further south to Kowanyama.
The weather bureau says it may not cross the coast but it will bring heavy rain to the Peninsula district.
Senior forecaster Ken Cato says the second system, a low in the Coral Sea, is 355 kilometres north-east of Townsville and is moving slowly south-south-west.
He says it should intensify into a cyclone today and residents between Lucinda and St Lawrence should take precautions.
"At the moment the most likely scenario is that it will get very close but curve away a little bit," he said.
"It should get close enough to cause some rain in more exposed parts of the coast but that should be more like showers as it moves just a bit away from those areas."
A cyclone warning has been issued for coastal areas from Lucinda to St Lawrence.
The bureau says heavy rain is expected to develop near the coast and adjacent inland areas from Cardwell to St Lawrence and it may lead to flash flooding.
Residents in the path of either system are advised to take necessary precautions.
Fisheries that rely on short life species, such as shrimp or sardine, have been more affected by climate change, because this phenomenon affects chlorophyll production, which is vital for phytoplankton, the main food for both species.
Fisheries that rely on short life species, such as shrimp or sardine, have been more affected by climate change.
Disclosed by the research “Socioeconomic Impact of the global change over the fishing resources of the Mexican Pacific” headed by Ernesto A. Chávez Ortiz, from the National Polytechnic Institute (IPN).
Work performed at the Interdisciplinary Center of Marine Sciences (CICIMAR) from the IPN, indicates that in the last five years there have been no “spectacular” changes attributable to climate change, what has affected the fishing resources more is the over demanding market.
“Globally, a great part of the fishing resources is being exploited to its maximum capacity, several have overpass its regeneration capacities and are overexploited” Chávez Ortiz points out.
The specialist at CICIMAR details that the research consisted in exploratory weather and fisheries analysis, and confirmed what has been intuitively said for a while: a lot of the variability in the fishing is due to climate change, the problem is that evidence hadn’t been found to prove it.
“In the research we found a clear and objective way to show it: we took historical data from FAO regarding fisheries, available since 1950, compared it to the data of weather variability and found high correlations.
Change patterns were identified, for example, while in the 70’s the sardine production increases, in the 80’s it decreases below average levels, meanwhile shrimp fishing increased above average but decreased in the 90’s.
This way, climate changes were identified in the mid 70’s and late 80’s that affected the fishing of sardine and shrimp in the Mexican Pacific Ocean, possibly attributable to El Niño. In the particular case of the shrimp, it effects are related to an input of water from the continent; for example, when there’s a good raining season, there will be an increase in the crustacean production, which is reduced when it doesn’t rain.
The researcher at CICIMAR clarifies that the analysis of the fisheries, examined in the guidelines of this project, used of a simulation model that allows to evaluate optimal exploitation strategies, possible change in the biomass of the analyzed resources, as well as the long term effects of climate change, like cyclones, and set them apart of those caused by the intensity of the fishing. (Agencia ID)
AN expert on Sydney Harbour’s marine life has taken out a new award from the Australian Academy of Science.
University of NSW marine ecology professor Emma Johnston, inaugural winner of the Australian Academy of Science's Nancy Millis Medal for Women in Science. Photo: Supplied
The academy has marked International Women’s Day today by presenting its inaugural Nancy Millis Medal for Women in Science to University of NSW marine ecologist Emma Johnston.
The award is for early-and mid-career women scientists who have established independent research programs and demonstrated exceptional leadership in any branch of the natural sciences.
Professor Johnston is a faculty member at UNSW’s School of Biological, Earth and Environmental Sciences. She also heads the Sydney Harbour Research Program at the Sydney Institute of Marine Science, a collaboration of universities and government agencies.
The five-year project aims to help inform the management of the harbour’s natural and economic resources. Professor Johnston said the harbour was one of the most biologically rich in the world.
“Below the surface we find extensive kelp forests, sweeping seagrass meadows, rocky reefs and vibrant sponge gardens all teeming with life. (But) humans have used oceans for waste disposal for generations because they have little emotional attachment to what’s under the water.
“We need to get political will and resources going to clean it up.”
Professor Johnston’s research focus is the effects of pollutants on estuarine life, taking both an ecological and ecotoxicological perspective and “using field experimentation wherever possible”, her web page says.
Her research has taken her from the tropical waters of the Great Barrier Reef to Antarctica, where she has studied the impact of climate change on ecosystems on the polar seabed.
UNSW deputy vice-chancellor (research) Les Field, who is also the academy’s secretary for science policy, said Professor Johnston was a deserving recipient.
“Emma is a research powerhouse in marine science and an academic leader at UNSW as well as being an excellent role model to younger scientists, both here and across Australia.”
Have you ever been snorkelling or scuba diving on a windy day when there are lots of waves? Did you notice how much that flow of water against your body affected your ability to swim and control your movements underwater? Well, fish feel the same way!
Changing waves and currents can keep fish on the move. Photo: Jordan Casey
Water flow, in waves and currents, plays a huge role in determining whether fish can survive in freshwater or marine habitats. Some species, such as tuna or salmon, are designed for high speed swimming, and thrive in fast flowing water.
Others, such as pufferfish, are not so well equipped to handle the challenges of living in high flow environments, and prefer the peace and calm of sheltered lagoons.
Stay calm. Photo: Flickr/ Motelface, CC BY-NC-ND
But even good swimmers have their limits. For example, high rates of water discharge from hydroelectric dams can hinder the upstream movements of fish – think of North American salmon or Macquarie perch in Australia.
Not all individual fish are affected the same, of course. Bigger, stronger adults are generally more capable of fighting against strong currents, but smaller, younger fish will be less likely to make it. This has obvious consequences for the age structure and survival of fish populations in the long run.
Waves, coastlines and coral reefs
On the Australian coastline, waves created by winds are a major physical force that fish have to contend with.
Some fish species are “rovers” without a fixed home range, and constantly swim over large areas in search of food or mates. Examples include species of surgeonfish and parrotfish. Since they do not need to defend a territory, these fish can take advantage of waves to help them move around, much like surfers do.
In contrast, many other species, such as damselfish, have small territories that they defend vigorously against unwelcome intruders to protect their food and other resources. To do this, they constantly have to swim against the water flow to avoid being swept away.
Colleagues and I have found that fish spend a lot more energy when they have to swim against big waves compared to a regular, steady current at the same average speed. This makes sense: humans also burn a lot more energy during interval training (when constantly changing between a sprint and a jog) compared to running at a constant speed.
Shiner surfperch in swim tunnel.
Many fish species regularly face these challenges, especially on Australia’s Great Barrier Reef.
Coral reefs are shallow habitats because corals need light to photosynthesise and produce their food. Because of their proximity to the surface, coral reefs are often very wavy habitats. This poses a real challenge for the estimated 25% of marine species found on coral reefs, 4,000 of which are fish.
Climate change
Researchers are increasingly concerned that accelerating changes in weather patterns are affecting fish and other aquatic organisms. Rivers, lakes and coastal habitats are ecologically, socially and economically important places, so it’s worth investing the time to research the impacts of climate change on these areas.
How disturbances from waves affect the movements of predators and prey likely depends on their relative size. Photo: Jordan Casey
In addition to warming temperatures and acidified oceans, sea surface levels, and thus tidal amplitudes, are also predicted to rise as a consequence of climate change.
Already, these trends in weather are being documented. Storms are also increasing in frequency and intensity in ocean basins around the globe, according to the chapter on Ocean Change in the International Panel on Climate Change’s report last year. With higher winds and larger tides come bigger waves.
Waves, tides and currents are an everyday part of life for fish living in fast-flowing waters, but new extremes in wind speed and wave height may push some species over the edge.
What can fish do?
If waves are costly for some fish, then why don’t they move to calmer locations? Fish can swim, after all. And some won’t even have to swim very far to reach calmer waters. Water velocity can vary across very small scales on coral reefs.
A new underwater instrument was developed at James Cook University to measure wave forces on the sea floor.
The instrument on a sheltered reef location with the guide rod construction and drag-sphere placement. Photo: Jacob L. Johansen, CC BY
A study from January this year using this device showed that water speeds decrease dramatically the deeper you go on coral reefs at Lizard Island. On a windy day, the water flow speed at 9m below the surface is about one quarter of the flow speed at 3m depth.
But there are many reasons why fish might not move to calmer reefs or go deeper to avoid waves:
sunlight is reduced with increasing water depth, so the shallowest, and waviest, part of the reef, where corals receive the most sunlight, is also the most productive and best habitat for fish
waves near the surface mix the water and carry the nutrients and plankton that feed fish
good places to live are at premium on coral reefs and species are all vying for space. This means that fish wanting to move will have to compete with already established residents and dislodge them if they want to take over their homes.
What can we do?
Our understanding of how fish deal with waves, let alone adapt to changes in their flow environment, is very limited.
Answers to many important questions remain elusive – what aspects of their shape, physiology and behaviour allow certain species to thrive in their current habitats?
How do waves affect important phenomena like the outcome of predator-prey encounters, competition between individuals, or the survival of small, larval fish on the reef?
How does water flow interact with other stressors like temperature changes, ocean acidification and fishing pressure in shaping our changing marine communities?
Ultimately, more research into these questions will help us understand how fish might respond to expected changes in their flow environment. These answers will be critical to inform marine resource managers and help them identify and target species that are especially sensitive to increases in wave intensity.
Dominique Roche receives funding from the Australian Research Council Centre of Excellence for Coral Reef Studies.
Push for emergency allocation of water to save fish stocks
Government at this stage unlikely to approve request
Local water authority says running channel to Toolondo not an option
FISHING enthusiasts, together with the local community are fighting hard to save fish stocks in Lake Toolondo in the south-west Wimmera.
"Rocklands is full of carp and does not support the same ecology you get at Toolondo." Trevor Holmes.
A group has been formed with two goals, in the long-term to shore up the future of the lake, described as the most important trout fishery in mainland Australia, and in the short-term to get an emergency allocation of 5000 megalitres of water to stop fish from dying.
One of the spokesmen for the group, Trevor Holmes, said the immediate challenge was to save trout stocks within the lake.
“The lake was restocked in 2011, and it seems silly to make that investment and then just let the fish die, when they can easily be saved with a relatively small amount of water.”
In the longer term, Mr Holmes said he wanted to see a minimum level retained in Toolondo where possible.
“It is a storage and does not evaporate quickly, so by putting in water you are not jeopardising the region’s water security.”
Mr Holmes said Toolondo had a much more significant eco-system than Rocklands, which is the region’s major storage.
“Rocklands is full of carp and does not support the same ecology you get at Toolondo.”
He said Toolondo was not only important for sporting fish but had healthy populations of native fish, eastern long necked turtles, yabbies and water-based birds and insects.
The group is lobbying Victorian Minister for Water Peter Walsh on the matter.
A petition on online petition platform www.change.org has over 1300 signatories and a Facebook group has over 1100 members.
However, thus far there has been little progress.
Minister Walsh said decisions for Toolondo’s management were made by the local water authority, Grampians Wimmera Mallee (GWM) Water.
"While the Victorian Government recognises Lake Toolondo has been providing some great fishing opportunities for recreational fishers, it is vital that the Wimmera-Mallee system is managed responsibly and as a whole,” Mr Walsh said.
"The stock and domestic supply of local landholders could be jeopardised if more water is transferred into Lake Toolondo for recreational fishing, given the current levels of Rocklands Reservoir.
"While in the past few years flooding rains have allowed for transfers from Rocklands Reservoir into Lake Toolondo, it would be irresponsible to transfer water under current conditions."
GWM Water spokesman Andrew Rose said the short-term allocation of water would not be a prudent move.
“The water losses in running water up the open channel from Rocklands to Toolondo would be massive.”
He also said Toolondo was not a preferred storage, not because of evaporation issues as in other GWM storages popular for recreation usage, such as Lake Lonsdale near Stawell, but because of topography.
“It’s true we can get water out of Toolondo, but when it gets to a certain level we need to pump it out, which obviously will increase costs.”
Mr Holmes disputed the water security argument.
“On our calculations, based on current water levels, running the 5000mL up to Toolondo would only drop Rocklands by 3cm.”
President of the Horsham Fly Fishers and Trout Anglers Club Gary Marlow said having lived through the Millennium Drought, which crippled the Wimmera from 1997 to 2007, he understood the importance of water security.
However, he said transferring water to Toolondo was not a risk at current storage levels.
“We understand if there is just no water about then it couldn’t be done, but we believe this lake has significance from an environmental, economic and recreational perspective and should be maintained.”
Both Mr Marlow and Mr Holmes questioned water management practices, such as summer environmental flows down the Wimmera and Glenelg Rivers.
“If we are trying to mimic the natural catchment patterns, then I don’t think you would have seen water running during our dry summers,” Mr Holmes said.
He said he realised the difficulties in getting the group’s requests through given the current water management framework.
“Longer-term, we’re certainly going to be working to get a more common sense approach to managing water resources.
“I know everyone wants their own lake filled, but in the case of Toolondo, there is a really strong argument, this lake has a massive reputation among the fishing community as a showcase trout fishery and we believe it can be filled without impacting on water security throughout GWM’s area.
