The Housatonic River and its tributaries used to be eel heaven.

Migrating upstream, these snaky fish would look for a nice place to settle down. Because they're a relatively long-living fish, they like to find a nice pond to call home.

"Lake Waramaug used to be a great place for eels," said Steve Gephard, a biologist with the Inland Fisheries division of the state Department of Energy and Environmental Protection.

The stories, Gephard said, tell of eels as thick as your wrist being taken from the lake as they began the southward migration to their spawning grounds in the Sargasso Sea in the Caribbean.

But those days ended several decades ago, when Connecticut Light & Power Co. began building big hydroelectric dams on the Housatonic.

"Eels can manage small dams," Gephard said. "They can just wiggle up over them."

But a big dam is too great a barrier to cross. Either the eels dried out in the sun as they worked their way to the top, or predators would grab them.

There are still eel migrations from Long Island Sound into the lower reaches of the Housatonic, but their numbers decline at a dam in Derby and drop even more at the Stevenson Dam in Monroe.

"Above the Shepaug Dam, you won't find any," Gephard said about the hydroelectric project in Southbury and Newtown that creates Lake Lillinonah.

That could be changing.

The DEEP and FirstLight Power Resources, which owns the hydroelectric system on the Housatonic, are now working on eel ramps for the Stevenson, Shepaug and Bull's Bridge dams.

"They're more like eel elevators," Gephard said.

Basically, each dam will have a ramp approximately 6 feet long. The eels will crawl up them. At the end of the ramp, there will be a bucket. The eels will fall into it.

Once a week or so, Gephard said, DEEP staffers will take the eels in the bucket, measure them and study them, then take the bucket to the top of the dam and spill the eels in.

Why this effort? The eel is a fish that looks like a snake. Unless you're a sushi fan, you will probably never sample eel flesh.

"They're not charismatic," Gephard admits.

But they are really interesting. They're North America's only catadramous fish -- they mature in freshwater, or the briny waters of estuaries, only to swim back to their spawning grounds in the Atlantic Ocean.

There, they breed and die. They're the opposite of salmon, which live in the ocean but breed in fresh water.

The eel we have -- the American eel -- may have the broadest diversity of habitat of any fish in world. It's found in Greenland and Brazil.

Because it's highly adaptive, it's been around for a long time. It can absorb oxygen through its skin and gills, allowing it to live out of water for a limited time. It exudes slime, hence the phrase "slippery as an eel."

Historic records show there were a lot of them in the upper Housatonic and its tributaries. Without them, Gephard said, the environment may be out of whack without our knowing it.

"They were in lakes, ponds, rivers, swamps," he said. "You just know instinctively they had to play a large part in the ecosystem."; 203-731-3345