At 11:07 AM 4/22/97 -0500, Jon Eynon wrote:
>If you, as a fisheries biologist, had to manage a reservoir with a severe
>phosphorous load problem that was causing a boom in smalll zooplankton and
>therefore gizzard shad production, what techniques would you deam most
>1. Siltation traps on incoming streams, reducing siltation and P load.
>2. Educate land owners on the lakes shores about proper land management.
>3. Introduce a large number of piscivores (ie. hybrid stripers) in an
>effort to try top down bio-manipulation.
>4. Reduce number of roads being built through the watershed in an effort to
>In your opinion, if all of those techniques put together could not equal
>over %100, what percentage of effort would you put into each one? In other
>words, which one is the most important and by how much? How about any other
>techniques I did not mention?
The short answer is that you don't know without more information. How much
silt could you trap? At what cost? How big of an impact would education
have on human behavior? Etc. Etc. Etc. All the options could plausibly
improve your situation, but you are asking for a *ranking* of options, which
can't be done with the information available. To get more background on
these issues, especially the top down bio-manipulation approach, research
the numerous books and articles on Lake Mendota (see work out of U.
Wisconsin by Kitchell, Carpenter, and students). Also, the Chesapeake Bay
Program has a long history of attempting to control organic pollution in the
Bay, and they evaluated many of the same options you mention. It has taken
a fairly complicated computer simulation model to explore the question of
"What is best?", but progress is being made (a ban on P in detergents has
been the main success). In short, you need to get quantitative in order to
get a good answer to your question.
Sometimes a little help is worse than no help at all. :)
Department of Biology and Environmental Studies Program
Ashland, VA 23005
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