(Updated 04/25/11)
Media contact: Joy Hill, 352-258-3426;
Patricia Behnke, 850-251-2130
Background: Lake Tohopekaliga,
better known as Lake Toho, is a part of the headwaters of the
Everglades and is known for some of the best fishing in the
country. The lake contains large amounts of hydrilla, a plant that
provides food for a nonnative species of apple snail. The snails
are the primary food source for the endangered (Everglades) snail
kite. The FWC is involved in the management of this lake, which
includes continually controlling the growth of hydrilla.
What is hydrilla?
Hydrilla is a nonnative, submersed plant (go to http://plants.ifas.ufl.edu/node/183 for more
details).
Why does hydrilla growth need to be
controlled?
Hydrilla, a nonnative species, can grow so thick
that it causes flood-control problems, shades out native plant
species, and can suffocate fish by lowering oxygen levels below its
dense canopy. Hydrilla control is important for maintaining the
fish and wildlife habitat that supports the fishery, and for
maintaining boat channels and fishing access for tournaments and
other local tourism.
The FWC strategically controls hydrilla in
important areas of the lake every year to allow fish and native
species of plants to thrive, to allow water to flow quickly when
heavy rains occur, and to maintain boat access into and throughout
the lake. Without annual hydrilla control, reduced boat access
could cause severe economic hardships and, eventually, loss of
native habitat and a decline in fish production.
How has hydrilla been controlled
in the past?
One or two applications of chemicals (herbicides)
are usually applied each year. Under normal circumstances, most of
the hydrilla is controlled on Lake Toho with one application of
chemicals in the winter.
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Why are changes being
made to hydrilla control on Lake Toho this year?
In the past five years, Lake Toho has become the
most important breeding area in all of Florida for the (Everglades)
snail kite, which is one of the most endangered birds in Florida
today. These birds have started to feed on large, nonnative apple
snails that invaded the lake in 2005. These large snails the birds
depend on eat hydrilla, among other plants, and the snail kites are
able to capture them while they feed and breathe near the water's
surface in the tops of hydrilla plants. Removing hydrilla from
areas where kites are nesting makes it harder for the birds to
capture snails and lowers the number of young birds that kites can
raise on the lake.
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What changes have been
made recently to hydrilla control on Lake Toho to help with the
endangered snail kite population?
In the past two years, the FWC and the U.S. Fish
and Wildlife Service have changed how hydrilla is controlled on
Lake Toho to eliminate impacts to snail kites. This new approach
involves letting some hydrilla grow where large numbers of kite
nests usually occur and conducting hydrilla control in other areas
in the late fall/early winter instead of the spring. This approach
was not very successful during the first attempt in the winter of
2008-2009, and too little hydrilla remained around kite nesting
areas during the early spring months of 2009.
To ensure that hydrilla would be available near
kite nesting areas during 2010, a more conservative
hydrilla-control approach was taken in the winter of 2009-2010.
However, severe cold weather brought complications, and hydrilla
was killed back throughout the lake, including the important kite
nesting areas.
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What changes will occur during
the winter of 2010-2011?
Because of the critical need for snail kites to
raise more offspring next year and the unexpected large losses of
hydrilla in the past two years, the FWC and the U.S. Fish and
Wildlife Service are taking a very cautious approach to controlling
hydrilla in the winter of 2010-2011. To ensure that kites will have
hydrilla during the early nesting season of 2011, hydrilla will be
controlled only in areas of the lake where water must flow freely
for flood-control purposes, where it restricts boat access at
public boat ramps, and where the majority of navigation is likely
to occur.
This may result in a substantial loss of open-water
areas in the northern portion of the lake, with navigation possibly
restricted to several wide boat trails by mid-summer 2011. The
majority of open-water areas will likely occur in the middle and
southern portions of the lake. Additional chemicals may be applied
in the spring and summer of 2011 to maintain flood-control
channels, boat ramp access and navigation trails.
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Will the change in
management techniques for hydrilla impact the economy of the Lake
Toho area?
The increase in hydrilla on the lake is expected to
reduce the areas usable to boaters by summer 2011. Some have
expressed concerns that anglers and fishing tournament organizers
may choose to go to other lakes in the area. We are working
diligently with the local community to maintain lake access and to
provide safe navigation so this won't happen. The FWC and the USFWS
are working with local business owners and anglers to address many
of these concerns. We will continue to assess the network of
recreational and navigational channels and re-treat the hydrilla as
needed to ensure good access and where possible, actually increase
fishing success on the lake. The agencies are committed to address
local community concerns, while ensuring we successfully increase
the number of young snail kites raised on the lake, which is so
critical to the endangered population at this time.
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