04-05-2007, 10:10 PM
Bullfrog populations in Minnesota are spreading rapidly due to the popularity of bullfrog tadpoles being used in backyard water gardens. The Minnesota Department of Natural Resources (DNR) is concerned about the impact this species can have when released outside of its natural range.
"The adult bullfrog will eat anything that it can fit into its mouth," said Rich Baker, acting supervisor of the DNR Natural Heritage and Nongame Wildlife Research Program. "In southern states, bullfrogs even eat hatchling alligators. Recent research has also found that introduced bullfrogs frequently carry a fungus that is deadly to other frog species. The presence of bullfrogs in a water body will often result in the death of all other frog species in that water body."
In Minnesota, bullfrogs are native only to backwaters of the Mississippi River in the southeastern corner of the state. They are considered an invasive species outside of this native range. If left unchecked, the American bullfrog could eventually displace native species throughout Minnesota, according to the DNR.
Baker said some pet shops, aquariums and garden centers are currently selling American bullfrogs illegally. Bullfrogs (adults or tadpoles) cannot be possessed, imported, transported or sold for any purpose other than as fishing bait without a DNR permit. To date, no such permits have been issued and the DNR has no intention of granting such permits in the future.
Bullfrogs and bullfrog tadpoles are being sold under various names including Texas bullfrogs, Louisiana bullfrogs, and Florida bullfrogs, but they are all one species, the American bullfrog (Rana catesbeiana ). State law also prohibits homeowners from possessing bullfrogs.
To keep track of the status of Minnesota's frog species, nearly 1,000 volunteers carry out the annual DNR Frog and Toad Calling Survey each April. These volunteers have identified a growing number of bullfrog colonies throughout the state. Populations of bullfrogs are now found in 18 counties outside of their natural range, which is Houston and Winona counties.
Fourteen species of frogs and toads are native to Minnesota, including the northern cricket frog, which is listed as an endangered species in Minnesota. To learn more, visit the DNR's Web site www.dnr.state.mn.us.
"Don't let bullfrogs become the next zebra mussel, buckthorn, or Eurasian watermilfoil," Baker said. "People can help prevent the further spread of this problem species. Help Minnesota's frogs and toads by saying "˜No' to buying or selling bullfrogs."
"The adult bullfrog will eat anything that it can fit into its mouth," said Rich Baker, acting supervisor of the DNR Natural Heritage and Nongame Wildlife Research Program. "In southern states, bullfrogs even eat hatchling alligators. Recent research has also found that introduced bullfrogs frequently carry a fungus that is deadly to other frog species. The presence of bullfrogs in a water body will often result in the death of all other frog species in that water body."
In Minnesota, bullfrogs are native only to backwaters of the Mississippi River in the southeastern corner of the state. They are considered an invasive species outside of this native range. If left unchecked, the American bullfrog could eventually displace native species throughout Minnesota, according to the DNR.
Baker said some pet shops, aquariums and garden centers are currently selling American bullfrogs illegally. Bullfrogs (adults or tadpoles) cannot be possessed, imported, transported or sold for any purpose other than as fishing bait without a DNR permit. To date, no such permits have been issued and the DNR has no intention of granting such permits in the future.
Bullfrogs and bullfrog tadpoles are being sold under various names including Texas bullfrogs, Louisiana bullfrogs, and Florida bullfrogs, but they are all one species, the American bullfrog (Rana catesbeiana ). State law also prohibits homeowners from possessing bullfrogs.
To keep track of the status of Minnesota's frog species, nearly 1,000 volunteers carry out the annual DNR Frog and Toad Calling Survey each April. These volunteers have identified a growing number of bullfrog colonies throughout the state. Populations of bullfrogs are now found in 18 counties outside of their natural range, which is Houston and Winona counties.
Fourteen species of frogs and toads are native to Minnesota, including the northern cricket frog, which is listed as an endangered species in Minnesota. To learn more, visit the DNR's Web site www.dnr.state.mn.us.
"Don't let bullfrogs become the next zebra mussel, buckthorn, or Eurasian watermilfoil," Baker said. "People can help prevent the further spread of this problem species. Help Minnesota's frogs and toads by saying "˜No' to buying or selling bullfrogs."