TURTLES

Turtles are reptiles, most of whose body is shielded by a special bony shell developed from their ribs. The term turtle is usually used for the aquatic species, aquatic fresh-water turtles also being referred to as terrapins.

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.

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.

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 red-bellied 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 red-bellied 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

Exclusion
Generally not practical. Small areas can be fenced.

Cultural Methods
Routine drainage of fish ponds generally results in lower populations. Keep levees mowed to make aquaculture ponds less attractive to turtles. Drain rice irrigation systems during late summer to reduce populations prior to spring planting.

Repellents
None are registered.

Toxicants
None are registered.

Fumigants
None are registered.

Trapping
Can be effective at certain times and places.

Shooting
Can be used to reduce populations of turtles. Check for local restrictions before discharging firearms. Some states prohibit the shooting of turtles in ponds and lakes.




ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (Cooperative Extension Division, Institute of Agriculture and Natural Resources University of Nebraska-Lincoln, United States Department of Agriculture Animal and Plant Health Inspection Service, Animal Damage Control, Great Plains Agricultural Council Wildlife Committee).



GOT CRITTERS? WE CAN HELP
Wildlife Management Services uses a variety of integrated and ecologically responsible pest management techniques - depending on the circumstances of the problem, the extent of the damage, and public health threats. Call (800) CRITTER for the Wildlife Management Services office nearest you. You can also find an office in your area by using our Office Finder.