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Bad News
Good morning everyone, I have some bad news from New Zealand, the radio news is reporting this morning that Didymo has been found in the Tongariro, Wanganui and Whakapapa rivers in the central North Island. If this is confirmed it will be the first outbreak of the dreaded Rock Snot in the North Island.
Only time will tell how bad this could be, but under threat from this is the whole Taupo fishery, the greatest wild trout fishery in N.Z. and one of the best in the world.
Anyone who knows me will know that the Upper Wanganui is my favourite river, it is a real backcountry river with clear water and lots of good size Browns and Rainbows, I just hope it turns out to be a false alarm or that the Didymo algae does not thrive in the North Island as it does in the South.
Fingers crossed.
Mike. :( :( :(
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Re: Bad News
I'm surprised you kept it off this long. Didn't Didymo start in New Zealand? It spread like crazy here.
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Re: Bad News
Hey Gramps, Didymo came to N.Z.s South Iland about 3 or 4 years ago, it is thought that it originated in the States. But I understand it is a native of Europe and is mostly spread on wet gear - tramping, kayaking, rafting and fishing gear can all spread it if they are not cleaned and dried properly between water catchments.
All the best.
Mike.
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Re: Bad News
It's confusing according to what web site you're on. You're probably right that it started in Europe.
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Re: Bad News
Hi Mike,
I hadn't heard that. There's been false alarms before, hopefully this another one.
- Jeff
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Re: Bad News
"The native distribution of D. geminata is the cool temperate regions of the Northern Hemisphere, including the rivers of northern forests and alpine regions of Europe, Asia and parts of North America. Until its recent discovery in New Zealand, where it was introduced, it was never previously found in the Southern Hemisphere. The distribution of didymo in the last two decades appears to be gradually expanding outside its native range. Even within its native range, there have been reports of excessive growths in areas where it previously existed only in low concentrations"
extracted from:
http://en.wikipedia.org/wiki/Didymosphenia_geminata
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Re: Bad News
Hi,
I see in the on-line news the cells that were found so far have been "dead cells". Unfortunatley, that means live cells are probably present, just not yet located.
They were testing some copper based system for controlling it in some rivers (which appeared safe for other life forms in the rivers). If DOC and Fish and Game act quickly enough, it might be worth trying that before it takes hold. Unfortunately, that would require quick action to do something that probably wouldn't work anyway (unlikely to kill all of it, and it only takes a little and then you have a lot).
- Jeff
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Re: Bad News
And, here's a note from my Angler's club on felt soled boots:
"Putting your gear in a freezer will destroy the Didymo cells that
remain.
Particularly the felt soled boots. This would be a preferable treatment to
that currently espoused. The detergent application can not penetrate into
wet lines from a spray bottle and even laces of boots are problematic.
Even if it penetrates and gets wet the dilution effect of the existing
water contained in the lines and laces would prevent the action of the
detergent from working. It has to be very high concentrations."
- Jeff
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Re: Bad News
"Bugger!!!"
That is really bad news, sorry to hear it.
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Re: Bad News
Didymo has been recently confirmed in the Upper Delaware System. But an article says it was seen there in 1916. It may not thrive and become a major problem everywhere it's found. I hope not. There is still not enough known about this yet.
UPPER DELAWARE REGION ? Don?t give ?rock snot? a ride, urged the New York State Department of Environmental Conservation (DEC) recently, following the discovery of the aquatic nuisance algae, Didymo, in the Delaware River. The presence of Didymo has now been confirmed in the mainstem of the Delaware, as well as in the East and West branches. River recreationists are being asked to take precautions against transporting it to new locations.
Didymo (Didymosphenia geminata), an invasive species in New York, was discovered in a section of the Batten Kill in Washington County early this summer. It has also been found in Vermont, Quebec and several western states.
The unsightly algae forms mats in rivers and then becomes a barrier to native organisms such as caddis, mayflies and stoneflies. The decline in insect populations can cause a corresponding decline in fish populations. Didymo can also affect stream ecosystem functions and may alter the foodweb structure and river hydraulics.
Getting answers
It is unclear whether or not the pesky algae will thrive in the mighty waterway, since traditionally Didymo prefers cold waters with low nutrient levels. For unknown reasons, the algae appears to be adapting. ?It?s a potential concern in that it can form these dense mats that exclude some native benthic invertebrates,? said Don Hamilton, natural resource specialist with the National Park Service, Upper Delaware Scenic and Recreational River (NPS UPDE). ?But whether or not it?s ever going to develop here is unknown.?
In an effort to learn more about the single-celled diatom, Hamilton and Richard Evans, an ecologist with the NPS Delaware Water Gap National Recreation Area, have submitted a technical assistance grant request to increase the knowledge base about Didymo and develop a possible strategy for dealing with it.
?It?s part of an effort to better understand what causes it to occasionally bloom and develop an approach to managing it. To do this, we need to know what some of the environmental variables might be affecting these blooms,? said Hamilton. ?We don?t really have a good understanding of what causes Didymo to bloom in a particular location when it does, nor do we know enough about its natural distribution. Are we seeing new introductions and expansion of its range, or changes in its extracellular growth and formation of dense mats on stream substrate due to environmental conditions?? asked Hamilton.
The answers to such questions are sought after by others studying Didymo. Dr. Martina Potapova is a research scientist at the Academy of Natural Sciences in Philadelphia, PA, specializing in riverine algae and their uses as environmental indicators. According to Potapova, this is not the first time that Didymo has been documented in the Delaware. ?There was a record of Didymosphenia in the Delaware River in 1916, so it is definitely not a new arrival,? she noted. ?It is actually a species commonly found in colder and cleaner rivers, so we cannot say that its presence indicates some sort of pollution.
?On the other hand, the recent findings of big masses of Didymo in western streams, including those polluted by nutrients, are telling us that something might have happened to this species,? said Potapova. ?There are only hypotheses about what could have caused the Didymo to change its ecology and to become a ?nuisance? species. Perhaps it is a case of a rapid evolutionary change, when a random mutation was advantageous because it allowed the species to thrive in polluted rivers, and this mutation was supported by natural selection, perhaps something else.?