"Dave LaCourse" wrote in message
...
This was posted on a fly fishing forum in both NH and ME:

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Fly Fishing Guide Lawton Weber discovered the invasive algae Didymo on
the upper Connecticut River on June 25, 2007.
snip
George Adams: You fish the CT up north, I believe. Have you heard
anything about this? If it's up there, it will soon be throughout NE.
Stream cancer without a cure...... scarey. This could endanger the
Deerfield, Westfield, and Farmington to name a few rivers. And Maine
is just over the horizon from the upper CT. I understand that there
are rivers out west that are also infected, as well as some in Quebec.

Dave
Although , for reasons no one has been able to determine, Didymo has
recently started acting like an invasive species and forming large "blooms",
it is native to North America (and Northern Europe). So it is, likely
already endemic in most streams in New England, but the conditions that
cause it to become super aggressive may have not yet expressed themselves in
those other streams. In New Zealand and Australia it is not native, so it
is truly an invasive species there.
I have a theory as to why it may have recently started to become a problem
in its native area, and, if the theory is correct, is ample reason to
carefully clean fishing equipment before traveling from one watershed to
another, even if Didymo is endemic in both watersheds. My theory:
Didymo which was introduced to New Zealand (first described there in 2004),
from North America or Northern Europe, thrived there and perhaps slightly
mutated to a very aggressive form. This more aggressive form may then have
been brought back to North America on fishing equipment or boats, etc.

Bob Weinberger