Department of Inland Fisheries and Wildlife biologists were surprised to find smallmouth bass recently in an Aroostook County trout pond that was reclaimed from another invasive species just two years ago.

According to a DIF&W release, the bass are not holdovers, but are a new species that was illegally introduced after the state had killed and removed the original illegal introduction of largemouth bass.

“This is just the latest, and most brazen, of the acts that we have uncovered,” said John Boland, the DIF&W’s director of fisheries program development. “These illegal acts threaten a sportfishing industry that pumps $300 million a year into the Maine economy.”

Biologists reclaimed Durepo Lake in Aroostook County at a cost of more than $20,000 in order to get rid of largemouth bass that had been illegally stocked there.

Reclaiming a pond involves spreading a chemical called Rotenone, which depletes the water of oxygen as it dissolves. The organic chemical then breaks down, making the water hospitable to fish again.

Reports of smallmouth bass in Durepo Lake came in an anonymous phone call to the Ashland Regional office of the DIF&W. The caller claimed to have caught two small smallmouth bass near the dam at Durepo.

Biologists used a portable electroshocker to confirm the presence of smallmouth bass in the lake.

According to the DIF&W, illegal introductions of fish species are now an epidemic.

Between 1980 and 2000, bass became established in 196 new waters. Between 1985 and 2000, the population of black crappies spread from 13 lakes to 64. And over a four-year period between 2001 and 2004, the number of documented northern pike populations has increased from nine to 30.

Anyone with information about illegal introduction of fish into Maine’s lakes and ponds can call 1-800-ALERT-US to report the act.

Aquaculture smelts being raised

Mike Hachey and Dr. Linda Kling at the University of Maine have succeeded in raising rainbow smelt from eggs to the size of about 1.5 inches, the DIF&W says.

That early stage of a smelt’s life cycle is the most critical hurdle in the goal of learning how to raise the delicate species in a “closed” aquaculture system.

A closed system is one in which there is not a constant addition of clean water. Instead, filters are relied upon to maintain good water quality. The effects of many factors on growth and survival rates of larval smelts are also being investigated, including various water-quality factors, lighting regimes and assorted feeding protocols.

Smelts are an important recreational sport fish and are vital as forage to many highly desirable sport fish such as salmon and togue. In fact, the vitality of landlocked salmon populations in a water body is directly related to the abundance of smelts. If smelt populations crash, so will the salmon population.