[Bristol-Birds] Bufflehead and alage problems at the weir

From: "Wallace Coffey" <jwcoffey@xxxxxxxxxx>
To: "Bristol-birds" <bristol-birds@xxxxxxxxxxxxx>
Date: Sun, 16 Jan 2011 19:27:47 -0500
It has been called to our attention that the Bufflehead population,
which frequents the South Fork Holston River weir dam,
may be affected by "Didymo"  an algae that has spread 
from Canada - its in the Holston and to some degree in the 
Watauga rivers in Northeast Tennessee and the Pound River in
Southwest Virginia.  

Could this also be affecting other waterfowl species which
no longer inhabit the weir dam in larger numbers and
more frequently as a wintering area ?  Several species seem 
to be in decline there in winter.

Didymosphenia geminata, also known as "didymo," is a 
single-celled algae that is firmly established in our rivers below 
dams. It is a non-toxic diatom that has the ability to colonize 
and cover entire river bottoms.  It is believed that it is here to 
stay and cannot be managed.

For food, the Bufflehead mainly feeds on insects and small 
crustaceans. They also eat seeds from plants. 

Because of the extensive smothering of rocks and other underwater 
structures, habitat and food sources can be changed or eliminated 
to the detriment of other organisms living in infested waterways.

The spread of this algae into our local rivers is among some of the
first ever recorded for this species in eastern North America and
has been mostly known for the past five years.

Biologists expect that the algae has been brought into our streams
on fishing boots and fishing equipment.  While there is no direct
reference that I am aware, there is always the possibility it has
actually been carried on the feet and legs of migrating waterfowl
which travel here from infected areas in Canada.  It is believed that
our local source of the algae has come into this country from Canada. 

This is not a far-fetched imagination or speculation.  Doug Ogle,
former editor of Castanea, the journal of the Southern Appalachian 
Botanical Society,  published a paper suggesting that the best 
explanation for halophytes at Saltville, VA is that the plants were 
carried there by waterfowl.  Halophytes are plants that naturally 
grow where they are affected by salinity.  The costal plants
now found at Saltville are not believed to have come from Virginia's 
costal areas but from more northern localities.

Outbreaks of didymo are thought to have contributed to the declines 
of freshwater invertebrate and vertebrate populations, especially fish 
The quality of infested waterways is severely reduced because large 
clumps of algae mass float down stream.

Didymo is thought to be native to some areas of North America, but 
historically it was rare in areas in which it was present. Currently, 
didymo is expanding its range in North America and its presence has 
been confirmed from Vermont, New Hampshire, New York, Virginia, 
West Virginia and Tennessee, among others.  

 
Let's go birding . . . 

Wallace Coffey
Bristol TN
[Bristol-Birds] Bufflehead and alage problems at the weir

Other related posts:
