Do Turtles Harm Ponds?

     We lost count of how many pond management seminars Bob has presented across the nation during his 37-year career. At every event, no matter how large or small, someone asks if turtles harm ponds. You may be surprised. The answer is–no.

When folks see large turtle populations, they fear turtles are eating fish. Professor James T. Davis with the Texas A&M University System at College Station says studies show typical turtle diets contain less than five-percent fish. Research further revealed most fish eaten by turtles are dead when turtles find them. Although turtles don’t harm fish, they annoy anglers by eating fish food or robbing bait from hooks. At present, there is no sure method for eradicating or restricting their use of ponds. A small number actually is beneficial.

Most common varieties are red-ear slider, soft shell, and snapping.

Red Ear Slider – Females are usually larger than males. Typically, they live between 20 and 30 years. Some have lived more than 40. Life expectancy is shorter in captivity. They are unable to regulate body temperature and completely dependent on temperatures of their environment. Consequently, they must sunbathe frequently to warm and maintain comfortable body temps. Red- eared sliders originated from warmer climates around the Mississippi River to the Gulf of Mexico. They remain close to water unless searching for new habitat or when females leave to lay eggs.

Common Snapper – Snapping turtles exhibit a combative disposition out of water. They have powerful beak-like jaws, plus a highly mobile head and neck. Lifespan in the wild is undocumented, but long-term mark-recapture data from Algonquin Park in Ontario, Canada, suggest a maximum age over 100 years. Common snapping turtles often are the heaviest native freshwater turtle. Males are larger than females. Most weigh more than 22-pounds. Males get quite old and grow throughout life. Snappers are important aquatic scavengers that consume plant and animal matter. They are active hunters and prey on anything they can swallow including snakes, smaller turtles, unwary birds, fish, frogs, reptiles, or small mammals. In some areas, adult snapping turtles can be detrimental to breeding waterfowl, but their effect on such prey is frequently exaggerated. Common snapping turtles are very aggressive if caught and have a strong bite that can easily cut-off human fingers.

Softshell – Sometimes they are called pancake turtles. Softshells include some of the world’s largest freshwater turtles, though many can adapt to living in highly brackish areas. They are found in Africa, Asia, and North America. This unique species is called softshell because they lack horny scales on their shell. These turtles have multiple characteristics among their aquatic lifestyle. Many must be submerged to swallow food. Most are strict carnivores, with diets consisting of occasional fish, aquatic crustaceans, snails, amphibians, sometimes birds, and small mammals. They have elongated, soft, snorkel-like nostrils. Their necks are disproportionately long in comparison to body size. This enables them to breathe surface air while submerged in substrate (mud or sand) a foot or more below the surface. Softshell turtles are eaten as a delicacy in most parts of their range, particularly East Asia. Softshells breathe underwater with rhythmic movements of their mouth cavity. This ability contains numerous processes that are copiously supplied with blood, acting similarly as gill filaments in fish.

When water temps approach 50-degrees, turtles swim to the bottom and hibernate until warmer weather. During this period, cardiac responses may drop 80-percent to conserve energy. They will stay submerged as long as the air is as cold as the water.  However, if you get a few mild, sunny days, you may see them warming on an object at the surface.

Trapping is the most practical and efficient way to control numbers. Submerged traps are needed for snappers and soft-shells. Surface models are most effective for sliders and other types that bask in the sun. Trap sizes vary with targeted species. Baiting underwater traps is essential for success. Bait may include fish, frogs, chicken parts, cottonseed cake, or soybean cake. Bait should be placed in a perforated can and suspended from the top of the trap so it can disperse odor and not be cannibalized or washed away. Freshen bait and remove critters every two or three days. Many folks in Texas and Louisiana consider turtles fine meat. If you plan to eat them, check daily. Trap location is important to success. Place near pond inlets in three to four-foot depths. As catch rates decline, move to a new spot. Surface traps are most successful in ponds with few floating logs, stumps, or islands that provide sunning habitat. Surface units should be removed and stored during winter since turtles are not active in cold water. Some species such as alligator snapping or painted turtles are protected by federal and state law. Contact a biologist if you cannot make positive identification.