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Re: Knowledge Extrapolation

Hi Ed,
  I lived on a small (16 acres) for many years in Virginia.
I moved there when I was about 9or10 so some things I just
don't remember as well as I would like.  I watched the lake
change over the years, when I first encountered the lake, it
was clear and beautiful.  It began to cloud up over time
with what I assume was a unicellular algae.  That was
followed by a higher plant (don't remember what, but as I
recall it looked similar to hydrilla) that totally clogged
the lake from one end to the other.  Rowing was not
possible, it was more like scooting.  It was so bad the the
weeds would clump together and sink to the bottom in the
fall.  Every spring when the water warmed the clumps would
surface again (probably supported by the gas formed due to
decay underneath).  They would be lager every year till they
got big and solid enough that I could actually stand on a
few larger ones.  The lake association contacted the state
for help (BTW the city considered the lake a ravine, that
way they didn't have to help out with $).  A state rep came
and did a number of tests.  The conclusion was that people
on the lake had used to much lawn fertilizer and it had
washed into the lake.  The rep suggested educating the
lakefront owners, a water change (there was a dam), and the
addition of "Israeli" carp.  These fish supposedly eat three
times their own body weight a day and are genetically
sterile.  The fish look like the large European mirror carp
and they do get BIG (40+ pounds).I feel that because the
fish are so big, fewer are needed.  This is an advantage if
they ever need to be removed, as in one is easier to catch
than five.  The weeds began to decline more every year until
down to "normal" levels.  We did not have a significant
bloom of unicellular algae again either.  I suspect that it
was a combination of the afore mentioned things that did it
rather that just the carp.  I would hesitate adding carp
just as general principle, because amongst other things I
have heard of lakes that had carp in them that ran out of
food, in these lakes they did muddy the water by rooting and
in really bad cases even under tunneled the banks.   In my
opinion our case was pretty extreme, perhaps you could get
away with out adding carp.  Maybe a call to your state
department would be good, they are used to dealing with this
sort of thing.

Best of luck
Bjorn Straube
Now of smoky and finally wetter east central Florida (yippee