SULLIVAN – There’s something in the water at Little Tunk Lake.

A couple of years ago, biologists with the state Department of Inland Fisheries and Wildlife found smallmouth bass in the eastern Hancock County lake.

The species is not native to that body of water, which means someone introduced the fish into the water illegally.

No additional bass have been found since, but DIF&W officials aren’t taking chances. They returned this week to dive and scour the waters of Little Tunk Lake just to be sure.

“This is an ongoing effort. We’re still not convinced there aren’t other adult bass there,” said Greg Burr, a fishery biologist at DIF&W’s regional office in Jonesboro. “We still haven’t found anything, and so far there is no evidence of nesting along shoreline, but once they start spawning, there is not a lot we can do.”

The bass in Little Tunk Lake shines light on what DIF&W spokesman Mark Latti called an increasing problem in Maine’s lakes and ponds. He offered a stern warning about the ecological effects of rogue stocking.

“It has far-reaching effects far beyond the water; it changes the ecosystem forever,” Latti said Friday from his office in Augusta.

“When a species like bass gets stocked, they are voracious eaters and compete for food supplies. Oftentimes [bass] are going to outcompete native species like trout or salmon,” Latti said.

Little Tunk Lake is a relatively small body of water, but because it feeds into Big Tunk Lake and other streams, when its ecology changes it’s not just one habitat that’s being affected, Burr said.

In recent years, many salmon fishermen have seen the effects of illegal stocking of pike species in many lakes and ponds. Now bass is becoming a problem as well.

Burr said that already this year biologists have found non-native bass in three lakes in Hancock and Washington counties: Jacob Buck Pond and Long Pond, both in Bucksport, and Pleasant Lake in Alexander.

“Every year we find new introduction,” Burr said. “Throughout the state we’ve documented 200 illegal instances of stocking since 1985, and that’s just bass.”

Stocking is not just an ecological nightmare, it’s a crime. Legislation in the past few years increased the penalty for illegal stocking. Anyone caught now faces a fine of up to $10,000 and possible jail time.

“We do take it very seriously, because it’s irreversible,” Latti said.

What officials aren’t clear on is why anyone would want to stock illegally.

“That’s a good question,” Latti said. “I think people believe one of two things: that they can bring a species they like to fish for closer to home or that they can improve fishing overall in that body of water.”

“Bass are easy to catch,” Burr offered. “They populate on their own. They are very adaptable. They grow fast, get big and they are good eating. They cover all the reason why people would want to fish.”

DIF&W has a program in place called Operation Game Thief that offers a $2,000 reward for information on any stocking activity that results in a conviction. Residents and anglers can call the hot line anytime at (800) ALERTUS.

“We encourage anyone who find bass, pike or other species of fish not native to specific lakes to call us,” Burr said. “The people that are doing this don’t think they’re going to get caught or they think they’re doing something good. Sometimes they just don’t care.”