Are piranhas invading Tennessee waters?

A couple of weeks ago a fisherman on Percy Priest Lake was catfishing with a chunk of hot dog when he got a bite – and almost got a second bite when he landed the fish.

What he brought in wasn’t a catfish but a piranha, a species native to the Amazon and famous for its flesh-eating ferocity.

The fisherman said the piranha snapped its toothy jaws and tried to bite him when he unhooked it.

The 8-inch orange-colored piranha was not the first one discovered in area waters. Last year a dead piranha was found in Old Hickory Lake, and a couple of years earlier one was caught by a fisherman in the Cumberland River below Cheatham Dam.

Fisheries biologists with the Tennessee Wildlife Resources Agency confirmed that in each of the cases the fish were, indeed, fresh-water piranhas.

But they insist there’s no cause for alarm – area waters are not being invaded by schools of ferocious man-eating fish. They say the piranhas that have been found in three Middle Tennessee lakes are simply aquarium pets that were released into the water by irresponsible owners who grew tried of caring for them.

Biologists say the tropical piranha could not survive a Tennessee winter or establish a breeding population.

However, recent winters have been relatively mild, and species are known to adapt.

A classic example is the armadillo, a native of the southwest which over the years has gradually increased its range into the Southeast.

Several years ago armadillos began appearing in West Tennessee, and eventually migrated across the Tennessee River. Today can be found in many Middle Tennessee counties.

Back to piranhas: The TWRA is concerned about the dumping of ANY non-native fish into the water. Some species, while not as ferocious as piranhas, can be much more destructive.

Any invasive species has the potential to cause serious problems when introduced into new habitats, the grass carp being the most recent example. They can disrupt the natural ecology and have a negative impact on native species.

For that reason it is against the law to release any non-native species of fish into state waters. Fishermen are even advised not to empty minnow buckets into the water at the end of a fishing trip -- there is always a chance that some invasive species of minnow could be mixed in with the bait fish.

And of course that don’t-dump regulation applies to aquarium fish and other exotics.

In the case of piranhas, individual fish could cause problems even if they don’t reproduce. As predators they are attracted to splashing, which could make them a threat to swimmers or anyone else in the water. A bite from a single stray piranha would be unpleasant.

The fisherman who recently caught the Percy Priest piranha joked that he “wouldn’t be doing any swimming” in the lake. If more piranhas show up, the joke may not be so funny.