Slippery Predator Invades A Nj Lake

Slippery predator invades a lake

Wednesday, September 24, 2008
BY BRIAN T. MURRAY
Star-Ledger Staff

In terms of foreign wildlife species invading North America, the Asian swamp eel is about as ugly as it gets.

Snake-like and aquatic, it can change its sex -- a convenient quality when trying to breed and infest new turf. It's a deadly predator, gobbling up all manner of aquatic life. Yet, in times of drought, the slippery creature also can remain burrowed in mud for weeks without food or crawl ashore and walk to a more suitable environment.

"It's pretty bizarre," said Chris Smith, a principal fisheries biologist for the state Division of Fish and Wildlife, as he walked the shallow, rocky edgewaters of a small Camden County waterway last week, netting dozens of the eels.

Hundreds of the invaders were discovered this year slithering and breeding in and around Silver Lake in historic Gibbsboro, the first infestation reported in New Jersey. Four states have now made the unwelcome discovery.

Smith said it is believed someone had the eels as exotic pets and dumped them in the waterway at least four years ago. Clad in waders, he and colleague Eric Boehm walked the perimeter of the 15-acre lake, using an electrical prod to shock the eels out of their muddy, rocky dens and scooping them up with nets. Some were as small as earthworms, others more than 2 feet long.

"They've survived winter freezes, so they're obviously highly adaptable," Smith said. "Right now, this is a control method. Our goal is to eradicate them."

The concern is the invader will prey on, diminish and one day displace native wildlife species. The eel feeds on invertebrates, fish, reptiles and amphibians, according to state biologists and the Aquatic Nuisance Species Task Force, an organization representing several U.S. government agencies.

The eels have no known native predators, can feed in and out of water, and survive in dried ponds or swamps devoid of oxygen as well as fresh or brackish waters.

"Anytime you have a non-native species here, there is a potential impact on native wildlife, as we have seen with other invasives," Smith said. "We don't know yet what the impact will be, but we want them gone before then."

Believed to have been let loose in Hawaii about 100 years ago, the eels first turned up on the mainland in a Georgia pond in 1994. By 1997, they were in parts of Florida where they are now approaching the Everglades National Park.

In Hawaii and Florida, biologists link the invasions to Asian food markets and inadvertent fish-farm releases. But in Georgia and New Jersey, amateur aquarium owners are getting the blame.

"We suspect someone let a couple of pets go," said John Biagi, a fisheries biologist at the Georgia Department of Natural Resources, noting the eels are a popular feature in aquariums as well as a culinary delight.

The Georgia eels were first discovered in a pond upstream from the Chattahoochee River, and were soon found in another lake nearby.

"We think they crawled to the other lake. The lakes are small, more like ponds, and we have found them in two. They also have been found in the river, but not downstream," Biagi said.

No one has developed a method for annihilating the creature. For now, Georgia, like New Jersey, is working to contain them.

New Jersey has yet to assess the extent of its invasion, but wants to prevent an expansion downstream to the Cooper River and a watershed leading to the Delaware River.

"We're not panicking yet," said Lisa Barno, chief of the New Jersey Bureau of Freshwater Fisheries. "It's more that it's just an invasive species we'd rather not have. We're still documenting the true extent of the problem, but right now it seems to be fairly contained."

The eels were discovered in Gibbsboro by a local college student. Checking on frogs and turtles one evening last May, the student instead found snake-like heads peeking from the lake.

The student knew something was different. He posted photographs of the strange creatures on the internet in May, prompting some identifications and, eventually, a call to state wildlife officials.

Since then, only one eel has been found outside Silver Lake -- at the head of the only tributary draining it.

The lake itself played an integral part in the area's history. Lucas Paint Factory opened on its banks in 1852, spurring the rise of Gibbsboro but also introducing an industry that last spring led federal officials to declare the area downstream a Superfund site.

Today, the lake area is a picturesque corporate campus where joggers and strollers regularly use the path surrounding the waterway. Blissfully unaware of the sinister creatures lurking beneath, they largely ignored Smith and Boehm as the biologists scooped up a total of 50 eels last week.

"The first time we came here to do this, we were getting them in greater abundance," Smith said. "Maybe it's a seasonal thing, maybe they're deeper in the lake or lake bottom now, or maybe what we're doing is very effective. Who knows?"

Brian Murray may be reached at bmurray@starledger.com or (973) 392-4153.

http://www.nj.com/ne...x...&thispage=2

I wonder if this is something NANFA members could assist in. Seems as these invasives are getting more and more common. Has anyone here had experince teaming up with state fisheries departments for exotics removals?

Edited by keepnatives, 29 September 2008 - 01:19 PM.

I want get in exotic removal program as its sounds like fun....kill the exotics and have nice fish dinner

Would be real nice to have a picture of the critter.

greg

Check this thread, Greg.

http://www.aquariace...ad.php?t=152009