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Re: Knowledge extrapolation

>Date: Fri, 03 Jul 1998 23:55:37 -0400
>From: Ed Hengel <hengel at computer_net>
>This may be a little off topic, but, how much of what we know about
>closed aquatic systems do you think applies to larger aquatic systems,
>say a 15 acre lake?  The one behind the house is, to my eye, a thing of
>beauty.  A healthy balance of flora and fauna with clean, clear water. 
>However there are those here in our community who think that we should
>introduce tripoid grass carp to get rid of the "weeds".  My position has
>been, based on my experience with my aquariums, that if we get rid of
>the aquatic plant life, especially by introducing a non indigenous
>species, albeit sterile, that we have little control of, the system will
>destabilize, algae will take over and the water quality will suffer. 

I snipped a little, but I think the rest is pertinent.

Ed, I'd keep fighting to keep plant shredders out of your local pond.  If
your neighbors really want to see what happens when there is no aquatic
plant life in a lake, maybe they can come down to Texas and have a little
look at Lake Texoma.  I know this lake isn't totally devoid of
macro-plants, but for the most part, the shorelines that I've seen have
willow trees and rice as their closest-to-an-aquatic inhabitant.  The lake
itself is basically blue-green to look at.  The water out in the middle is
good for maybe 2 meters of visibility, but there is a ton of silt and
unicellular algae that clouds much of the lake.  In many of the ponds
around the lake, a nice, thick layer of spirogyra floats at the surface,
making every cast and reel return a hook coated with hair algae.  These
ponds drain cow pastures and are often very green, depending on the number
of willow trees and cattails along the banks (more trees -> clearer water)
and the amount of spirogyra on the surface.  I haven't seen any native
aquatic plants in these ponds though, and you can tell by looking at them.

Or, maybe they would like to clear the pond of cover for the smaller,
bug-eating fish with their grass carp.  Who knows?  Maybe they should just
introduce Nile Perch or something.....  Oh gosh, I'm getting way too
sarcastic now.

I would recommend against upsetting the equilibrium in your pond by
introducing any exotic.

David W. Webb  
Live-Foods digest administrator
live-foods at actwin_com