Turtles
General Turtle Facts
Identification and Range
Turtles occur on all continents except
Antarctica. Over 240 species occur
worldwide but turtles are most abundant
in eastern North America. Most
turtles have good field characteristics
that are visible and can be easily identified.
Some species, however, require
close examination of the shields on the
plastron (underside shell) for a
positive identification.
General Biology,
Reproduction, and
Behavior
Any permanent body of water is a
potential home for turtles. Some species
will also tolerate brackish water,
but the sea turtles are the only true
saltwater species.
Unlike most other turtles, including
soft-shells, snapping turtles rarely
bask. Turtles feed on a combination of
plant and animal material that
includes items such as aquatic weeds,
crayfish, carrion, insects, fish, and
other small organisms. The diet of
snapping turtles, however, usually
includes a relatively high proportion of
fish. They are relatively aggressive
predators, occasionally known to take
fish off fish stringers.
All turtles reproduce by laying eggs in
early spring. Hatching begins in late
summer and extends into the fall,
depending on summer temperatures
associated with the climate of the
range. During winter, turtles usually
bury themselves in soft mud or sand in
shallow water with only the eyes and
snout exposed.
Turtles are easy prey for a number of
predator species such as alligators,
otters, raccoons, and bears. Humans
are probably the greatest threat to
turtle populations, particularly for the
most commercial species, such as
snappers and soft-shells.
Damage
Turtles are seldom a pest to people.
Turtles are very beneficial and of economic
importance, except in certain
areas such as waterfowl sanctuaries,
aquaculture facilities, and rice fields in
the south. Indiscriminate destruction
of turtles is strongly discouraged, and
every effort should be made to ensure
that local populations are not exterminated
unless it can be clearly demonstrated
that they are undesirable.
Some species of pond and marsh
turtles are occasional economic pests
in rice fields in the south. Their feeding
activity on young rice often results in
significant yield reductions in local
areas.
In farm ponds, turtles undoubtedly
compete with fish for natural food
sources such as crayfish and insects.
Turtles, however, are valuable because
they kill diseased and weakened fish,
and clean up dead or decaying animal
matter.
In commercial aquaculture production
ponds, turtles can eat fish that are
being grown. They also eat fish food.
Aquaculture ponds are not the preferred
habitat of turtles, however. The
heavy clay soils required for pond construction
are not conducive to the
turtles’ laying of eggs.
Legal Status
Most turtles are not protected by state
laws. Licenses usually are required for
commercial fishing and sale of turtles.
Before taking turtles, contact a state
wildlife or conservation agency representative
for legal status.
There were two turtles listed by the
US Fish and Wildlife Service as endangered
or threatened species as of
December 1992. The desert tortoise
was listed as threatened everywhere
except for a population in Arizona. Its
historic range is Arizona, California,
Nevada, and Utah. The gopher tortoise
was listed as threatened wherever
found west of the Mobile and
Tombigbee rivers in Alabama, Mississippi,
and Louisiana. Its historic range
is Alabama, Florida, Georgia, Louisiana,
Mississippi, and South Carolina.
Five freshwater turtles were listed by
the US Fish and Wildlife Service as
endangered or threatened species as of
December 1992. The Alabama redbellied
turtle and the flattened musk
turtle were listed as endangered and
threatened, respectively. Alabama is
the historic range of both species. The
ringed sawback turtle is threatened in
its historic range of Louisiana and
Mississippi. The yellow-blotched map
turtle is threatened in its historic range
of Mississippi. The Plymouth redbellied
turtle is endangered in its historic
range of Massachusetts.
Additional species under review
include the alligator snapping turtle,
bog turtles, and the western tortoises.
Damage Prevention and
Control Methods
Cultural Methods
The best control for box, pond, and
marsh turtles in rice fields is to drain
irrigation canals and fallow fields during
winter months. Without a permanent
water source year-round, these
species do not reach large enough
populations to become a serious economic
problem.
Ponds that are used for the production
of channel catfish or other finfish are
routinely harvested by seining. The
seining process will also capture
turtles. Farmers can control turtle
populations by moving these captured
turtles to their natural habitats.
Repellents, Toxicants, and
Fumigants
None are registered.
Trapping
Since turtles generally are not a pest to
people, control measures are limited
primarily to trapping. Trapping can be
used quite effectively to reduce local
populations of these species where
damage occurs.
The best place to trap turtles is in the
quiet water areas of streams and
ponds, or in the shallow water of
lakes. Soft-bottom areas near aquatic
vegetation are excellent spots.
The best seasons for trapping are
spring, summer, and early fall. Most
turtles hibernate through the winter,
except in the extreme south, and do
not feed, making trapping ineffective.
Methods of trapping are described for
various types of turtles in the following
sections.
Traps should be baited with fresh fish
or red meat. Catfish heads and cut
carp are regarded as two of the best
baits available for trapping turtles.
Baits should be suspended in traps on
a bait hook or placed in bait containers
for maximum effectiveness. In areas
where turtle populations are high, it is
often necessary to check traps two or
three times per day and add fresh bait,
since turtles are capable of consuming
large quantities of bait rather quickly.
Snapping and Soft-Shell Turtles.
While snapping turtles are in hibernation,
they often can be taken in quantities
from spring holes and old muskrat
holes, under old logs, and in soft bottoms
of waterways. Turtle collectors
rely on their hunting instincts and
experience to locate hibernating
turtles. When one is found, it pays to
explore the surrounding area carefully
because snappers often hibernate
together. The method for capture,
known as “noodling” or “snagging,”
requires a stout hook. One end of an
iron rod is bent to form a hook and
sharpened; the other end of the rod is
used for probing into the mud or soil
to locate the turtles. The hunter probes
about in the mud bottom until a turtle
is located (which feels much like a
piece of wood) and then pulls it out
with the hook. Turtles are inactive during
the winter and offer little resistance
to capture, although the landing of
large ones may be difficult even for
experienced hunters.
Snappers and soft-shelled turtles are
sometimes taken on set lines baited
with cut fish or other fresh meat. One
recommended device is made by tying
4 or 5 feet (1.2 or 1.5 m) of line to a
stout flexible pole, 6 to 8 feet (1.8 to 2.4
m) long. About 12 inches (30.5 cm) of
No. 16 steel wire is placed between the
line and the hook, preferably a stout
hook about 1 inch (2.5 cm) across
between barb and shaft. The end of the
pole is pushed into the bank far
enough to make it secure at an angle
that will hold the bait a few inches
(cm) above the bottom.
Snappers and soft-shelled turtles may
also be taken readily in baited fyke or
hoop nets (Fig. 2). These barrel-shaped
traps may sometimes be purchased on
the market or made from 3-inch (7.6-
cm) square mesh of No. 24 nylon seine
twine. The trap should be 4 to 6 feet
(1.2 to 1.8 m) long from front to back
hoop. The three to five hoops per trap
should be 30 inches (76 cm) in diameter,
made of wood or 6-gauge steel
wire with welded joints. The funnelshaped
mouth should be 18 inches (46
cm) deep from the front hoop to the
opening inside. The entrance opening
of the funnel should be 1 inch x 20
inches (2.5 x 51 cm). The corners of the
opening are tied by twine to the
middle hoop. The rear or “box” end
may be closed with a purse string.
After the hoops have been installed,
the net should be treated with a preservative
of tanbark, cooper oleate, tar,
or asphalt. To keep the trap extended,
stretchers of wood or steel wire, about
9 gauge or larger, are fastened along
each side.
Coarse mesh poultry wire may be substituted
for the twine. If this is done,
the frame will be approximately 30
inches (76 cm) square. The shape and
dimensions of the entrance as specified
should be the same in all traps, as it is
easily negotiated by the turtles. The
dimensions of the trap may be altered
for ease of transportation. A door may
be installed in the top to facilitate baiting
and removal of turtles. Entrance
funnels may be placed on each end if
desired.
Fyke or hoop turtle traps should be set
with the tops of the hoops just out of
the water. This will permit the turtles
to obtain air and lessen their struggles
to escape, and will enable other turtles
to enter the trap more freely. It is necessary
to set traps this way if the turtles
are to be taken alive. Traps set in
streams must be anchored. If the water
is too deep for the top of the trap to be
out of the water, short logs can be
lashed to each side to float the trap.
Turtles enter more readily when the
mouth of the trap is set downstream.
Box, Pond, and Marsh Turtles.
Because of their habits, these species
must be captured with methods different
from those for snapping and softshelled
turtles. They cannot be taken in
numbers during the winter, like snappers,
because they do not congregate
in their hibernating places. In the summer
some species are gregarious,
crowding together in numbers on projecting
logs and banks. By taking
advantage of this fact, these basking
species may be taken by trapping in a
box sunk in a place the turtles are
using. The turtles crawl up onto the
top of the box to bask in the sun, and
many of them fall into the trap (Fig. 3).
The top frame of the box may be constructed
from discarded telephone
poles, imperfect ties, or logs about 8
inches (20 cm) in diameter. Old natural
unpainted wood is preferred. The logs
are mitered at each end to fit together,
and the inside enclosure made to measure
2 to 3 feet (61 to 91 cm) square.
About half of each log from the top
center to the inside under center is
lined with zinc or galvanized metal.
Turtles that have dropped into the trap
are unable to climb over the zinc or
galvanized metal covering. From the
outside water edge to the top of each
log, cleats can be nailed or the logs
made rough, so turtles can easily climb
on top. Galvanized mesh wire can be
fastened to the logs with staples,
hooks, or wire to form a wire basket
fitting the opening between the logs.
One-inch (2.5-cm) mesh is about right
if all sizes of turtles are to be trapped.
If only larger specimens are sought,
however, a 3-inch (7.6-cm) mesh can
be used. The trap should be fastened
to a stump or some other permanent
anchor.
Some trappers prefer to use bait;
others leave the traps unbaited. For the
capture of snapping and soft-shelled
turtles, the trap can be modified by
installing funnel-like entrances on one
or two sides as described for the hoop
traps.
Another type of trap consists of a box
with an inclined board leading up to it.
The turtles climb up on the board to
bask and drop off into the box. Figure
4 shows the same trap with pivotal
boards placed so that turtles crawling
out on the boards overbalance on the
terminal end and are dropped into the
box.
Shooting
In some states, shooting can also be
used as a means of reducing populations
in ponds and lakes. This technique,
however, is not very effective.
Economics of Damage
and Control
Three groups of turtles are of economic
importance in North America.
They include the snapping turtles; the
box, pond, and marsh turtles; and the
soft-shelled turtles. Snapping turtles
are trapped for human consumption
and are being considered for aquaculture.
Red-eared turtles are cultured
for the foreign pet trade. Soft-shell
turtles are also trapped for human
consumption.
Damage is typically of little economic
concern, but may be a problem in rice
and aquacultural production.
*The above information was taken from a University of Nebraska Web site with
express permission of Stephen Vatassel, wildlife damage project coordinator. |
