Post by JoeOverlock on Aug 23, 2007 19:30:38 GMT -5
American was likely source of didymo
By JOHN HENZELL - The Press | Saturday, 18 August 2007
www.stuff.co.nz/4168718a7693.html
An American angler visiting New Zealand was the likely origin of the didymo plague that threatens to cost the country up to $285 million.
Biosecurity New Zealand had samples of didymo – an invasive freshwater alga known as rock snot – from outbreaks in the United States, Canada, Iceland, Britain and Europe compared with samples taken from South Island rivers.
"Phylogeographic analysis using didymo DNA samples from populations around the world indicates that a North American population is the most likely source of New Zealand's introduction," Biosecurity spokeswoman Judith Hamblyn said.
The samples were collected after Biosecurity officials were among 60 experts who attended an international didymo conference in the US last year, at which the economic impact of the invasive weed to New Zealand over the next eight years was estimated to be between $57m and $285m.
North Canterbury Fish and Game spokesman Steve Terry said the analysis suggesting North American origin of New Zealand didymo confirmed what was widely suspected.
"It most likely came in with felt-soled waders because didymo can last on them for months," he said.
Didymo has been found in many Canterbury streams and rivers, but so far prohibiting fishing in high-country streams had prevented it becoming established in the crucial spawning grounds, where it threatened to devastate the fishery, he said.
"We're doing our best to educate anglers, but you'll always have 1 per cent of people who don't care. There are also trampers, jetboaters, four-wheel-drivers and possibly birds who are spreading it," Terry said.
Didymo was found in New Zealand in 2004, the first time it had been found in the southern hemisphere.
Since then, research by National Institute of Water and Atmospheric Research scientists presented at the conference in Bozeman, Montana, last year showed didymo was impossible to eradicate in streams once it had become established.
The cost of didymo to the New Zealand economy includes loss of commercial eel fisheries and damage to water supplies, tourism and biodiversity values.
New Zealand is not the only country struggling with didymo, with Canadian authorities attributing its spread in particular to felt-soled anglers' waders.
North American outbreaks of didymo range from near Anchorage, Alaska, to as far south as Arkansas.
British researchers said didymo had been present in Britain for more than 150 years, but algal blooms appeared to be a natural phenomenon and were not spreading to other river catchments.
Large masses of didymo have been found in the European Alps and the Carpathian mountains.
By JOHN HENZELL - The Press | Saturday, 18 August 2007
www.stuff.co.nz/4168718a7693.html
An American angler visiting New Zealand was the likely origin of the didymo plague that threatens to cost the country up to $285 million.
Biosecurity New Zealand had samples of didymo – an invasive freshwater alga known as rock snot – from outbreaks in the United States, Canada, Iceland, Britain and Europe compared with samples taken from South Island rivers.
"Phylogeographic analysis using didymo DNA samples from populations around the world indicates that a North American population is the most likely source of New Zealand's introduction," Biosecurity spokeswoman Judith Hamblyn said.
The samples were collected after Biosecurity officials were among 60 experts who attended an international didymo conference in the US last year, at which the economic impact of the invasive weed to New Zealand over the next eight years was estimated to be between $57m and $285m.
North Canterbury Fish and Game spokesman Steve Terry said the analysis suggesting North American origin of New Zealand didymo confirmed what was widely suspected.
"It most likely came in with felt-soled waders because didymo can last on them for months," he said.
Didymo has been found in many Canterbury streams and rivers, but so far prohibiting fishing in high-country streams had prevented it becoming established in the crucial spawning grounds, where it threatened to devastate the fishery, he said.
"We're doing our best to educate anglers, but you'll always have 1 per cent of people who don't care. There are also trampers, jetboaters, four-wheel-drivers and possibly birds who are spreading it," Terry said.
Didymo was found in New Zealand in 2004, the first time it had been found in the southern hemisphere.
Since then, research by National Institute of Water and Atmospheric Research scientists presented at the conference in Bozeman, Montana, last year showed didymo was impossible to eradicate in streams once it had become established.
The cost of didymo to the New Zealand economy includes loss of commercial eel fisheries and damage to water supplies, tourism and biodiversity values.
New Zealand is not the only country struggling with didymo, with Canadian authorities attributing its spread in particular to felt-soled anglers' waders.
North American outbreaks of didymo range from near Anchorage, Alaska, to as far south as Arkansas.
British researchers said didymo had been present in Britain for more than 150 years, but algal blooms appeared to be a natural phenomenon and were not spreading to other river catchments.
Large masses of didymo have been found in the European Alps and the Carpathian mountains.