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Lakewatch sampling expanded to include exotic species monitoring
Featured bird: snowy egret
Exotic species (cont.)
Volunteer bulletin board
Lake Tohopekaliga (Toho) enhancement project
LAKEWATCH Sampling expanded to include
Exotic Species Monitoring
Last year marked the 20th
anniversary of the Florida LAKEWATCH
program. Over this time period, all
aspects of the program have
expanded, including the amount and
collected by e
aquatic birds Photos of some of the exotic s
and angler with that of native apple snail E
catch diaries compared to a baseball. C) Pt
S parts of the Florida Peninsula.
evolved along the way as well.
Now, for the next step, we are
beginning to implement a survey of
exotic species. Exotic species are
those that are introduced from
another area. The purpose
document the reported
locations of exotic species *undesil
in Florida lakes. *reduce
Why exotic *increa(
species? Increasingly, we
have been asked to
provide information on exotic species
as citizens have come to recognize
their presence and are concerned
about the potential impact that
exotic species can have on native
systems. This is likely a consequence
of elevated public awareness through
media reports and a maturation of
the research concerning non-native
species and their ecological and
economic impacts. As citizen lake
managers, many of you are all too
familiar with the presence of exotic
JULIOu VVI IIL, I I luuiiu III VRIUIIu VVci tIO. ,ij rnIULU LuII/Jill
,gg masses. B) Photo depicting the size of the exotic apple
otos of the exotic armored catfishes (Hoplostemum littoral
aquatic plants and the associated
impacts they have had on your lake.
The same potential for lake-wide
change exists as a consequence of
other exotic species as well.
Ia Impacts from exotic species include
able changes in natural communities
;d production of desirable fisheries
ed costs associated with management control
Although a broad range of
research and monitoring of exotic
species exists, there remains more
unknown than known about their
ultimate impact. This is where you
come in. LAKEWATCHers who wish to
participate, are asked to report
sightings of exotic species.
One exotic species we have
frequently been asked about is the
Channeled apple snail (Pomacea
canaliculata). Originating from South
America, these herbivorous (plant
their range in
found in great
for most of the
ing exotic apple snail egg masses central and
snail and the native apple snail southern
) that are now found in many peninsula and
we would like
to further identify specific water bodies
with exotic apple snail populations. For
information on the biology and
identification of this species, the
channeled apple snail has been
featured in previous LAKEWATCH
newsletters (Volumes 30 & 35).
Remember, one of the
best indicators for the presence of
channeled apple snails are their egg
masses (see photo above). Egg
masses are attached to firm substrates
like dock pilings and emergent
vegetation located above the water
line. Egg masses contain between 100-
Exotic species continued on page 3.
F Bir Sow Er
I Ic UuuI I UIlUvv y LYi!Il 1.1 uoy IU iuc1iiily
if you see its feet. They are medium
sized white herons with black legs and
bright yellow slippers.
rT he Snowy Egret is a
member of the Heron Family (Ardeidae)
and it is frequently observed near Florida
water bodies. Its preferred habitats
include marshes, swamps, ponds, lakes,
shallow coastal areas, and tidal flats.
Occasionally the Snowy Egret is even
observed hunting in dry fields. The call of
this bird is a loud, nasal squawk that is
used in aggression or territorial defense.
The Snowy Egret is a small to
medium sized white heron with black
legs and bright yellow feet, which can be
used for quick identification. They are
active, slender birds with long thin necks,
dark thin bills, and long dark legs. This
species measures from 22-26 inches tall
with a wingspan of about 39 inches and
weighs around 13 ounces. The different
sexes look alike. In breeding season, the
Snowy Egret has long plumes on its
head, neck and back. The appearance of
immature birds is similar to that of adults
but their bills are pale at the base, they
lack plumes, and their legs are yellowish
with a black front edge.
A similar spedes is the Great
Egret, which is a larger bird with a yellow
bill and deep black legs and feet. Also
similar is the immature Little Blue Heron,
which has a stouter, bluish-gray bill,
greenish-yellow legs and feet, and no
yellow skin between the eyes and the base
of the bill. The white form of the Reddish
Egret is a larger, shaggier bird found only in
salt water and has a dark or bi-colored bill
with a pink base with dark legs and feet.
The Cattle Egret is much shorter and
stockier with a thick pale-colored bill, legs,
and feet. It also has a reddish colored
wash over its head, back, and chest.
In eastern North America, Snowy
Egrets can be found in their summer range
along the Atlantic and Gulf coastal areas
from southern Maine and inland across the
western USA to Texas and southward. In
winter, northern populations migrate to
southern coasts of the USA and southward
to Central America, South America, and
the West Indies. In warmer locations like
Florida, some Snowy Egrets become
permanent residents much like their
relative, the "Northern Snowbird," which
migrate to Florida to avoid higher taxes and
the ardors of winter snows and cold
The Snowy Egret eats fish,
insects, amphibians, crabs, and aquatic
invertebrates. They stalk their prey in
shallow water, often sprinting rapidly and
shuffling their feet to flush minnows and
shrimp. This unique feeding behavior can
be used to identify this species when
viewing their bills and feet is not possible. It
is thought that their white color and
sprinting behavior may attract other
"Snowies" that join each other in the feast
and as a result, they are often observed
feeding in small groups. Sometimes
Snowy Egrets practice "dip-fishing" by
flying with their feet just over the water.
They may also be observed standing still
waiting to ambush prey or stalking insects
stirred up by domestic animals in open
Snowy Egrets breed once a year.
The breeding habitat of the Snowy Egret
includes inland and coastal wetland areas
from the Great Lakes south to the south-
western US and down into South America.
They may wander north after the breeding
season, and occasionally are seen in
Western Europe. They usually nest in
colonies, sometimes along with other
wading bird species, on platforms built in
trees and shrubs about 7 feet above the
ground. Sometimes they even build their
nests on the ground.
The flat shallow nesting platforms
are made of sticks and are lined with
smaller twigs and softer plant materials,
including rushes and cattails. As with other
herons, the crudeness of their nests, the
elliptical form of their eggs, and other signs
suggest to some scientists that these birds
are one of the lower forms on the scale of
bird life. In other words, they are not that
far removed from the reptiles when
considering the big picture over eons of
The female Snowy Egret lays
from 3-5 greenish-blue oval shaped eggs,
which are then incubated by both parents
until they hatch 3 to 4 weeks later. There is
evidence that the members of a Snowy
Egret pair cannot recognize one another
except at the nest. Even there, a bird
arriving to relieve its mate must perform an
elaborate greeting ceremony in order to
avoid being attacked as an intruder. During
this display the plumes on the head are
raised and the incoming bird bows to the
one that is sitting. Satisfied with this
display, the sitting bird leaves the nest and
the other takes over. The young leave the
nest in 20-25 days and can be observed
hopping on branches near the nest before
At one point in history during the
latter part of the 19th century and into the
early twentieth century, the beautiful
plumes of the Snowy Egret were in great
demand by market hunters as decorations
for women's hats. This hunting pressure
reduced the population of this species to
dangerously low levels and they almost
became extinct! Since being protected by
law, the Snowy Egret population has
The Snowy Egret was observed
in 27 of the nearly 90 lakes participating in
the Florida LAKEWATCH Aquatic Bird
Survey. There were 141 sightings of this
bird to date and on 63 of these sightings,
only 1 bird was observed. However, on 9
sightings as many as from 10 to 57 birds
were sighted! The lakes with large
numbers of Snowy Egrets were generally
eutrophic to hypereutrophic lakes. Birds
were sighted during all months but there
was no apparent monthly pattern when
birds were more or less frequently sighted.
Exotic species continued from page 1.
200 grit-sized eggs (2 mm to 3.5 mm) and
are colored pink to reddish.
Other examples of exotic species
include two groups of exotic armored
catfishes that are now found in many
parts of the Florida Peninsula. The first
group of exotic armored catfishes are one
of the most rapidly expanding exotic
fishes: the brown hoplo or Hoplosterum
littorale (see photo (C) on page 1). This
catfish belongs to the South American
family Callichthyidae. Members of this
family are often called the mailed or
plated catfishes, a reference to their
armor. This small catfish (up to about 9.5
inches or 240 mm) is easily distinguished
from native and other exotic catfishes by
the overlapping plates of armor found on
its sides. There are two pairs of prominent
barbels (whiskers) around the mouth. It is
often seen swimming to the surface to
gulp air for breathing and can survive in
waters with little oxygen. They mostly eat
insects, worms, snails, and other
invertebrates. The brown hoplo builds a
floating, bubble nest in surface
vegetation and guards the eggs.
Although they can be very abundant in
some places, the effect of brown hoplos
on native species is unknown. Even
though they are small fish, some people
cast net for them and the meat is
The other group of armored
catfishes are the armored suckermouth or
sailfin catfishes. These are the familiar
"plecos" or "plecostomus catfish" found
in pet stores. There are 500 to 600
members of the South American family
Loricariidae, but the species in Florida
lakes are members of the genus
Pterygoplichthys. There are at least three
and possibly four species now in Florida-
P. anisitsi (maybe), P. disjunctivus, P.
multiradiatus, and P. pardalis. The species
are very difficult to differentiate, even by
experts. However, it is easy to distinguish
these catfish from native and other exotic
catfishes in Florida. Key characteristics
are the sucker-like mouth; hard, rough
skin; a single prominent (but short) barbel
on each side of the mouth; and a large,
sail-like dorsal fin. There are some
armored suckermouth catfishes of the
genus Hypostomus in Florida, but so far,
these have only been found in a few
streams near Tampa and in a few canals
near Miami. Although they look similar,
Hypostomus can be distinguished by a
Species of armored catfishes from the
genus Ptervaoplichthvs (commonly
known as the "plecos" or "plecostomus
catfish" found in most pet stores).
shorter dorsal (top) fin that has only seven
rays (as opposed to 10 or more in
Pterygoplichthys). Also, members of
Pterygoplichthys reach about 27 inches
(685 mm) whereas Hypostomus seldom
exceed 8-10 inches (200-254 mm). They
are adaptable to many water conditions,
including low oxygen, and may be seen
rising to the surface to gulp air. These
catfish eat primarily algae and detritus.
They dig burrows into banks or in
depressions on the lake bottom where
the female deposits a round mass of
eggs. The male guards and tends the
eggs. Very little is known about their
effects on native species or ecosystems,
but their burrows can cause local erosion.
Although the meat is said to be good,
these catfishes are seldom eaten in
If you observe any exotic
species, please report it to us. It is our
hope that the information gathered
from this study will further define the
range and distribution of exotic
species utilizing Florida's aquatic
resources. It will assist in determining
if negative impacts can be
attributed to the presence of these
exotics and what management
control activity is warranted.
On page 7 of this newsletter
and on our website there is an
exotic species report form that you
can use to report exotic species.
Please send the information to the
LAKEWATCH office by US mail or
contact us at 1-800-LAKEWAT (1-800-
Please do not mail
When reporting exotic species, try
to remember the 5 W's:
When it was observed,
Where it was observed,
Who saw it and
Why you think it was the
Quality pictures will greatly
increase the likelihood of correct
identification; so if possible, include
pictures in your reports.
When taking photos of an exotic
species place a ruler or coin next
to the exotic species for scale.
For the suckermouth catfishes, the
following photos will assist in
1) the side view,
2) the head from above, and
3) the suckermouth/chest/belly.
For the brown hoplo, the side view
of the fish is sufficient.
A Home for Florida LAKEWATCH
The campaign to raise $1,000,000 for a new LAKEWATCH home is underway!
The vision for a new "LAKEWATCH HOME" is an exciting prospect. When I met with leaders from various statewide
LAKEWATCH groups, their decision to help raise $1,000,000 was most gratifying. To date we have raised approximately
$40,000. We have received donations from individual LAKEWATCHERS and lake homeowner associations. Special
Richard and Ann Dominica
Nadine D. Foley
Jeffrey George and Rosemary Mahoney-George
Donald L. and Betty J. Millner
Paul R. and Paula B. Morrow
Chester and Foy Windsor
John and Phyllis Nelson
Bear Lake Preservation Association Inc.
Forest Lakes of Cocoa Condominium Association, Inc.
Lake Powell Community Alliance, Inc.
Property Owners of Sun-N-Lakes of Lake Placid Recreation District, Inc.
Robert and Terry Em
Richard and Justine Fry
Thomas C. Luche
Thomas and Ann Moore
Theodore and Joan Niermann
Lake Winnemissett CivicAssoc.
Daniel and Susan Canfield
Lake Broward Assoc., Inc.
John's Lake ImprovementAssociation, Inc.
Summerbrooke Property Owners Assoc.
Tallavana Homeowner's Association Inc.
This is a good start, but as you can see lots of hard work remains to be accomplished!
I am asking the fundraising committee to meet in Gainesville at the current LAKEWATCH home on January 27, 2007. This
meeting is to discuss what has been accomplished and what needs to be done to meet our $1,000,000 goal. Our goal is
very reachable if we all work together. If you are interested in participating in the fundraising campaign that is under way,
please contact me at (352) 392-9617 ext 246. New ideas and approaches are welcome!
Daniel Canfield, Jr., Professor of Limnology
Founder and Director of Florida LAKEWATCH
has a new e-mail
WANT TO GET YOUR NEWSLETTER
Due to many requests by LAKEWATCH vol-
unteers, we are now offering our newslet-
ters electronically. If you would like to re-
ceive the LAKEWATCH newsletter via the
internet, please send us an e-mail using our
new e-mail address and let us know. We will
use your e-mail to send the newsletter to
you in digital format in the future.
Want an algae sample identified?
If you have an algae sample that you want
identified please follow these simple steps:
1) Call your LAKEWATCH Regional Coordinator
to arrange for us to get your sample.
2) Collect your sample in one of your small
(250ml) sampling bottles.
3) Keep the sample in your refrigerator until
we can get your sample as arranged
with your Regional Coordinator.
4) DO NOT FREEZE the sample.
Thanks and Happy Sampling!
Sa Collection Center Update
The IFAS Extension Office at the corner of Michigan and Bumby is moving to
a new location in Febuary 2007. The new address will be 6021 South Conway
Road which is the section of South Conway Road between Hoffner Avenue
and McCoy Road. The telephone number will remain the same for the foresee-
able future. If you have questions about where to drop your samples or pick
up new supplies you can call Darla Wilks at 407-836-7570.
North Lake County
The collection center at the Visitors Center to the Ocala National Forest in
Altoona (the Pittman House) has been closed. We are currently working to
find another location in North Lake County to become the new collection cen-
ter. Until a new collection center can be set up please take your samples to
the Lake County Water Authority located at 107 N Lake Ave Tavares FL,
32778. The telephone number at the Water Authority is 352-343-3777. If you
are a Marion County resident, the closet collection center is the Silver River
State Park at 1425 NE 58th Ave., Ocala, FL 34470. The telephone number at the
State Park is 352-236-7148.
If you have any questions about any of these changes you can call us at 1-
800-525-3928 or e-mail us at email@example.com.
Please make note of this change!
Lake Tohopekaliga (Toho)
Over the course of 2004, the Florida Fish and Wildlife
Conservation Commission (FWC) administered a project to
consolidate the accumulated organic matter (muck from
decomposing plant material) along the littoral areas of Lake
Toho. When properly conducted, muck removal is an effective
lake management action capable of reducing nutrients and
harmful substances entrapped in the muck. Muck removal also
counteracts the accumulation of organic material due to
eutrophication, and was the principle goal for the Lake Toho
enhancement project. With the removal of sediments from lake
systems there are always some environmental concerns,
including the liberation of nutrients that were contained in these
sediments. To assess the impacts of this management activity
on Lake Toho's water quality, Florida LAKEWATCH was requested
to evaluate the key trophic state parameters: total phosphorus,
total nitrogen, chlorophyll and Secchi depth.
Lake Toho is the 7th largest natural lake in Florida with a
surface area of roughly 19,000 acres. With relatively shallow
depths, the littoral area of the lake
had been sustaining dense stands
of aquatic plants including -
emergent species such as Picker-
elweed (Pontederia cordata) and
submersed forms including Hydrilla .
(Hydrilla verticillata). This abun-
dance of aquatic plants in Lake
Toho was likely enhanced through
cultural eutrophication from
watershed development and *
through the stabilization of water .
levels for flood control purposes.
As a result, the aquatic plant
community flourished and contrib-
uted to the buildup of thick -,
deposits of organic matter on the
lake bottom, particularly along the
shoreline. Some of the conse-
quences of this buildup of shore-
line muck include lower dissolved
oxygen concentrations as a result
of increased biochemical de-
mand for oxygen, the covering of
sandy sediments used for sport fish ..
spawning beds and a reduction
of open water habitat for fish and Lake Toho is located in central
wildlife. Eutrophication had also Counth ladrpicted in topl lkie
changed the aesthetics and are shown on the lake with black
reduced the recreational oppor-
tunities of Lake Toho.
Ideally the muck deposits would be permanently
removed from the lake. However, finding uplands which can
hold the enormous volume of muck was not economically
feasible. Instead the majority of the material was used to
construct wildlife islands around the lake edge. To accomplish
this, the lake water level was drawn down approximately 7 feet
and then heavy equipment was used to scrape the plants and
muck off the underlying sand substrates from over
3,500 acres of the littoral zone. This material was
pushed into long rows, allowed to dry out, and then
formed into 29 artificial islands of 1 to 8 acres in size.
Following the lake enhancement project completion
in the summer of 2004, the average thickness of muck
in the scraped areas was reduced from approxi-
mately 18 inches to 1 inch.
During planning for the project, some natural
resource managers were concerned that these
islands may release nutrients into the lake, thus
reducing their intended benefit. To address these
concerns, Florida LAKEWATCH personnel were asked
to design a study to determine if the islands released
measurable amounts of nutrients to the lake and if the
construction of the islands caused changes in trophic
status of Lake Toho. As commonly occurs, an unin-
tended factor was added to the experimental design
when three hurricanes and
their associated high winds
/ .- and heavy rainfall passed over
-. the area in August and
S\ September of 2004. To
account for the effects of this
hurricane activity, we exam-
ined the total phosphorus
concentrations and color
values measured from 58
nearby lakes sampled by
Florida LAKEWATCH during the
same time period.
Our analyses of water quality
parameters in the vicinity of
the islands indicate that the
islands are not having a
significant impact on the
water chemistry of Lake Toho
through leaching of nutrients.
SWhile statistical analyses of
: long-term open water stations
y indicated that levels of total
Phosphorus, chlorophyll and
color were slightly higher and
dissolved oxygen were lower
Florida in Osceola following the enhancement
the photo). Lake Toho is project, these differences
orida. Sampling stations
k dots. most likely were the result of
hurricane activity. These
storms delivered 37 inches in August and September
of 2004 to the regions watershed, causing elevated
nutrients and organic materials to be washed into the
Lake Toho. This conclusion is supported by our control
sample of 58 nearby lakes which also showed signifi-
cant increases in both total phosphorus and water
color coinciding with the passage of the hurricanes.
Lake Toho continued on page 7.
Lake Toho continued from page 6.
We would have expected to find similar increases in Lake
Toho independent of the muck removal project. Following
the hurricanes, some islands were eroded from wind driven
waves, but the vast majority remain today as vegetated
islands. Currently these islands are being utilized by wildlife
such as alligators, several varieties of water snakes, aquatic
birds, and other animals. The outcome of this project
appears to have been successful, improving both the public
perception of the lake and the shoreline habitat for fisheries.
Included are pictures showing the dramatic changes made
to Lake Toho and a diagram showing the locations of the
resulting islands and water chemistry sampling stations.
(1) April 26, 2004,
(2) May 11,2004
Sequential pictures taken from Wayley's landing, Lake Tohopekaliga, during and after a lake enhancement project was conducted.
Pictures were taken on the following dates, respectively: April 26, 2004, May 11, 2004 and February 14, 2005.
EXOTIC SPECIES REPORT
When Observed (Date, mm/dd/yyyy):
Habitat observed in:
Who (Name and contact information):
Why (* Include pictures if possible. Any additional details):
Please return the exotic species report form above to the LAKEWATCH office by U.S. mail at:
7922 NW 71st Street
Gainesville, FL 32653
Or contact the LAKEWATCH office by phone or e-mail and report the information listed:
Toll-free Citizen's Hotline: 1-800-525-3928
LAKEWATCH's new e-mail address: firstname.lastname@example.org.
You can download another form from the LAKEWATCH website: http://lakewatch.ifas.ufl.edu.
Please do not mail
U*f UNIVERSITY of
Department of Fisheries and Aquatic Sciences
7922 NW 71st Street
Gainesville, FL 32653
This newsletter is generated by the Florida
LAKEWATCH program, within UF/IFAS' Department
of Fisheries and Aquatic Sciences. Support for the
LAKEWATCH program is provided by the Florida
Legislature, grants and donations. For more
information about LAKEWATCH, to inquire about
volunteer training sessions, or to submit materials
for inclusion in this publication, write or call:
7922 NW 71st Street
Gainesville, FL 32653
All unsolicited articles, photographs, artwork or other
written material must include contributor's name,
address and phone number. Opinions expressed are
solely those of the individual contributor and do not
necessarily reflect the opinion or policy of the Florida
LAKEWATCH program. Inclusion does not constitute
endorsement, nor does exclusion represent censure
of any item, organization, individual, or institution by
the University of Florida or the Florida LAKEWATCH
What is an Exotic Species?
An Exotic Species is any species that is not native to an area. So an exotic
species is also called a non-native species.
WHAT'S THE PROBLEM?
In their native ranges, species generally behave well, but when they
become established in non-native areas they replace and otherwise
destroy the native species that are supposed to be there. That's because
non-native species do not have their natural enemies such as: diseases,
water regimes and other stresses that keep them in check in their native
ranges. There are exceptions-for example Cattails are a native plant in
Florida but can become invasive in some environments like disturbed
When other species destroy and replace our native species, there can be
1) natural biodiversity is destroyed;
2) native species can be eliminated;
3) other species that are dependent on natives are usually not able to make
use of non-native species;
4) exotic species can completely take over an area;
5) recreational uses can be eliminated from areas with exotics.
You can help stop the spread of non-native species in Florida.
* Learn to identify which species are exotics.
* Never buy exotic species.
* Never collect, move or transport exotic species.
* Report exotic species by using the form provided on page 7.
Information summarized from http://plants.ifas.ufl.edu/guide/invplant.html.