February 26, 2013 - NEW ZEALAND - Tests are being carried out to determine what caused the deaths of more than 40 adult yellow-eyed penguins on the Otago Peninsula.
Officials hope the die-off does not become as bad as that of 1990 when almost 150 adult penguins died.
Department of Conservation (DOC) officer David Agnew said it took the penguin population in the area several years to recover from those deaths.
It was hoped the current deaths were being caused by a biotoxin occurring naturally in the marine environment, and for now it was assumed the fish the penguins were eating were making them ill.
40 Adult Penguins Die In Mass Die-Off On The Otago Peninsula In New Zealand.
"We're hoping that whatever is causing it, perhaps weather conditions affecting the water column, will dissipate so the penguins will return to normal, and hopefully penguin adults will stop dying," Agnew said.
The first dead penguin was found on January 21 and the latest were found last weekend, although some had been dead for some time.
"It's quite a blow," he said.
"In some cases, both the male and female of a pair might have succumbed to this."
Agnew, who is DOC's programme manager for biodiversity assets in coastal Otago, said staff were surveying more beaches today.
The dead birds had been sent to Massey University for autopsies. All had been found to have been in good condition when they died, without any obvious cause of death.
Two birds that had died recently were being sent to the Cawthron Institute to be tested for toxins.
It was hoped to have the results of those tests by early next week, Agnew said.
As well as the impact on the penguin population, another issue was that the birds were important for some tourism businesses.
He said the 40 deaths were spread over 13 breeding sites, so people visiting the sites were still able to see penguins.
As in 1990, dead birds were being found only around the Otago Peninsula, while penguins in North and South Otago were unaffected, Agnew said.
There were 450 to 500 breeding pairs around the South Island coast.
The timing was different in 1990, when the penguins started dying earlier, meaning many more chicks had to be taken into captivity, where they had to be looked after for much longer.
He said that was not such a big issue this time as the young birds were due to head out to sea about mid-February.
This summer had been good for chicks, with the young birds mostly reaching healthy weights. Any that were found to need help, perhaps underweight or with both parents dead, were being cared for.
"For us it's the loss of the breeding adults. They know how to survive, where to forage and where to breed," Agnew said.
A plan was being prepared to ensure as rapid a recovery as possible of
the yellow-eyed penguin population on the peninsula, he said. -
Stuff.
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| Lake Ginninderra. Photo: Carmel Nelson. |
Fish Kill In Lake Ginninderra In Canberra, Australia.
A redfin virus is believed to be responsible for a fish kill in Lake Ginninderra last week.
Staff from Territory and Municipal Services and the Environment Sustainable and Development Directorate were called out to clean up many hundreds of dead fish on Thursday last week.
A TAMS spokesman said the majority of dead fish were redfin, an introduced species, and a virus is the suspected cause.
“Tissue samples of the dead fish have been sent for laboratory testing in Sydney with results expected early next week,” the spokesman said.
“EHN or redfin virus, which has previously been reported in Lake Ginninderra and Lake Burley Griffin, is believed responsible. EHN poses no risk to human health.”
He said there was no correlation between the fish kill and the recent release of more than 30,000 golden perch fingerlings into the lake.
Any further sightings of dead fish in Canberra’s lakes and rivers should be reported to Canberra Connect on 13 22 81. -
Canberra Times.
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| Phytoplankton analysis of water samples taken from Marbellup Brook by the Department of Water confirmed the bloom was cyanobacteria Nodularia spumigena, a species common to waterways in the region. Image: Wikicommons. |
Great Southern Algae Bloom Kills Waterway Fish In Albany, Australia.
A SIGNIFICANT freshwater fish kill 15km west of Albany earlier this month has been attributed to a large bloom of blue-green algae affecting the waterway.
Residents in Elleker living adjacent to Marbellup Brook first notified water authorities of the bloom at the end of January when hundreds fish were found dead along a 1.4km stretch of water within the Torbay catchment area.
Phytoplankton analysis of water samples taken from Marbellup Brook by the Department of Water confirmed the bloom was cyanobacteria Nodularia spumigena, a species not uncommon to waterways in the region.
Nodularia is known to produce a liver-damaging hepatotoxin that can adversely affect birds and mammals, but evidence in the water samples showed no sign of any microalgae species toxic to fish.
Department of Water south coast regional manager Brett Ward says analysis indicated the algal bloom was in late stages of decomposition when samples were taken.
“During the decomposition phase [of an algal bloom] oxygen is taken up, which often depletes the system, as indicated by the very low oxygen levels present at the time of sampling,” he says.
“This supports the likely cause of the fish deaths being due to the low oxygen levels.”
At least 100 black bream and five mullet were officially recorded dead.
However, department staff were unable to obtain suitable fish samples for analysis due to decomposition, thus were unable to conclusively state oxygen depletion caused the fish-kill event.
Low rainfall over winter resulting in reduced stream flow, combined with recent hot weather has been attributed to the increased risk of algal blooms, which according to many Elleker residents have been a common occurrence throughout the Torbay catchment for 25 years.
The annual stagnation of Marbellup Brook also has residents concerned as provides conditions for the spread of mosquito-borne Ross River virus (RRV).
At least two recorded incidents RRV have been recorded in the area in the last seven years.
The Water Corporation has installed a temporary pumping operation in the affected area to help improve water circulation, aiming to minimise reformation of large algae blooms.
- Science Network.