Damage

Great Plains toad, Bufo cognatus

The greatest potential for economic damage is at fish farms and hatcheries. Tadpoles compete for food intended for fish, and adult bullfrogs may actually feed on the fish. Losses are said to be high at some fish farms. One study suggested that the mere presence of high densities of tadpoles retarded reproduction of fish. Although the bullfrog is native to most of the eastern United States, its introduction to portions of the west has seriously affected some native species. In at least some cases, these introductions may have resulted from the unintentional release of tadpoles during fish-stocking programs. Considerable labor is required to separate tadpoles from loads of fry.

Only in rare instances do frogs cause any significant damage. Some species (toads, for example) produce skin secretions that are toxic if ingested. This does not normally present a problem for people, and pets usually learn to avoid such frogs. A few species (giant toad, Colorado River toad) produce especially copious or toxic secretions, and there have been cases in which dogs have died after biting them.

The noise sometimes produced by large breeding choruses of frogs following heavy rains can be annoying to humans. These aggregations usually last only a few days, however, and seldom warrant control. Similarly, complaints sometimes arise when large numbers of young frogs leave the ponds en masse, but the frogs disperse quickly, and the “problem” will take care of itself in a few days.

Legal Status

Laws pertaining to frogs vary from state to state. Some rare species (for example, Houston toad, Wyoming toad, Pine Barrens treefrog) may be fully protected under federal or state laws. Seasons and bag limits may apply to other species (bullfrogs, for example). Permits to remove frogs that are causing damage are available in some states. Contact your state wildlife department to determine the legal status of frogs in your area.

Economics of Damage and Control

Frogs eat many insect pests. With the exception of fish farms, control measures for frogs are seldom warranted and, in most cases, should be discouraged. On fish farms, the economic damage depends in part on the unit value of the fish produced. Corse and Metter (1980) provided data suggesting that a 350-pond farm that produced goldfish might sustain $42,000 in annual losses to bullfrogs, whereas the same facility might sustain only $12,600 in losses if it produced golden shiners, a less valuable species. It follows that losses might be still higher on farms specializing in valuable aquarium fishes.