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Lake Ecology
Name: Jody
Location: N/A
Country: N/A
Date: N/A
Question:
We have a partically natural/ partially man-dug lake in
our back yard. It is approximately 3 acres in size. The fish in this
tiny like are plentiful and HUGE :) Bass up to 20"
s (so far) and blue gill up to 10"s (so far). My question is this... we
appear to have a heavy goose population and I was wondering if they are
the cause of the green slimmy stuff that is all over the top of the water
as well as the lighter green slime on the plants growing under the
water? Are the fish being harmed by waste from the geese and if so, what
can I put in the water to ensure their health?
Additionally, I noticed hundreds of frogs during the mating period yet
I've yet to see even one tad pole and I am at the lake atleast 5 out of
the 7 days in a week. Is there a reason for this. The frogs are two
toned.. light green with patches of darker shades of green on the head and
body. I've never seen frogs like these before but then again, I've never
lived in wet lands prior. The frogs are also very agressive... tend to
attack fishing line and even leap up to 4' in the air to attack a fishing
rod. Thank heavens they don't have teeth! . We do not keep the
fish we catch, we always release.
Replies:
Jody,
It sounds like a nice setup you have in your area.
Regarding suspected pollution of the water (the green film you mention):
it would not be advisable to add anything to the water....instead, the first
best approach in seeing what appears to be environmental problems, in my
opinion, is to find what is present that is causing the problem and trying
to remove it. Adding something else tends to magnify the problem in
unpredictable ways.
The green film might be from the presence of the birds you mention, but to
me it sound like an algal bloom (heavy presence of algae). This occurs
frequently in areas where there is a high nutrient level present in the
water (especially nitrogen fertilizers present as runoff from farmers
fields). I would investigate if there is any source of fertilizer or runoff
from adjacent farmed fields and, if so, determine if there is any way to
either plant vegetation to stop major water flows from the area into the
lake, or consider landscaping (which can be very costly for a lake your
size) which could shunt runoff from the suspected area away from the lake.
Because this may be a fairly minor problem, you might consider just
monitoring the problem to see if it is lessening over time naturally. To
not get involved in the problem and have it clear up naturally is the best
possible solution in most cases where environmental problems are concerned.
So long as the oxygen demand in the lake is not being exceeded by the
presence/eventually decay of the algal blooms, and so long as there is not a
(major) fish kill due to the loss of oxygen in the lake water, things should
be able to correct themselves.
Regarding the birds: it is possible that an overabundance of bird waste in
the water could provide sufficient 'fertilization' to create an algal bloom.
You could monitor the bird population over time and consider if it is
excessive for the area. Various communities throughout the United States
are battling with the problem of enjoying the presence of the migrating
birds, but reacting against the waste left in their wake. Seattle,
Washington, comes to mind, where Canadian Geese populations leave waste in
parks, etc. which makes even walking through the area a challenge for
people.
Good luck with your continued observations.
Thanks for using NEWTON!
Richard R. Rupnik
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Update: June 2012
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