AUGUSTA – Halting the spread of invasive aquatic plants such as milfoil without infringing on the rights of boaters and fishermen remains a challenge for state lawmakers.

On Thursday, the Natural Resources committee heard a wide range of views during a public hearing on a bill that would institute a mandatory inspection program at every public boat ramp on every lake where invasive plants had been discovered – a total of 14 lakes and 21 ramps so far, according to the Department of Environmental Protection.

Maine’s invasive aquatic plant problem will grow exponentially unless drastic measures are taken to prevent the spread of variable-leaf milfoil, hydrilla and curly leaved-pondweed within the state, and to halt the introduction of new problem species.

“Unless the spread of invasive aquatic species is contained, the $2 billion economic engine that we call Maine lakes will become an unsupportable expense and management problem. It’s just that simple,” Maggie Shannon, executive director of the Maine Congress of Lakes Associations, said Thursday.

However, even Shannon worried that the bill, LD 1723, might go too far too fast in a time of limited budgets.

The mandatory inspection program has a projected cost in excess of $120,000 annually – 18 percent of the state’s entire budget for invasive species management, according to Andrew Fisk, director of the Bureau of Land and Water Quality at DEP.

The high cost could “gut’ other crucial programs that have provided education about invasive plants and the investigations that led to the discovery of new infestations, Shannon said, testifying neither for nor against the bill.

If the bill were approved, public boat access on infested lakes would be limited to times agreed upon by the commissioners of DEP and Inland Fisheries and Wildlife when a boat inspector hired by the state could be present.

For Dave Barnes, a lobbyist for the Maine Bass Federation, such closures are unacceptable. Those wealthy enough to afford to belong to private marinas could maintain access to infested lakes while the general public – including guides, like himself, who make a living from fishing – could be shut out, he said.

“All you’re talking about in these bills is limiting who’s going to have access to these lakes … it’s the haves and the have-nots,” Barnes said, testifying in opposition to the bill.

Existing monitoring and management programs are sufficient to control Maine’s invasive-plant problem, he said.

“Milfoil has been blown up to be a great big giant green monster that’s going to run down Route 202 and eat us,” Barnes said.

The Bass Federation was in the minority Thursday, however, as representatives of several lakes associations and members of the scientific community stressed the urgency of the invasive-plant problem, often pointing to clogged lakes as testimony to what milfoil can do.

“We have a tiger by the tail. We have a limited amount of time available to do the work that we need to,” said Dan Buckley, a professor of biology at the University of Maine at Farmington who, with his students, has researched the variable milfoil infestation in Messalonskee Lake.

DEP on Thursday proposed an amendment to LD 1723 that would give the state explicit authority to close boat ramps to prevent the spread of invasive plants.

It would create the inspection program, but only as an option to be used for severe, high-risk situations, at the discretion of the DEP and DIF&W commissioners.

Last summer, the state’s limited monitoring program discovered that 43 percent of boats leaving Messalonskee Lake at the Route 27 ramp carried milfoil fragments, while at other lakes the figure was below 10 percent, Fisk said.

The department just doesn’t have the staff or the funding to intensively monitor all 21 public boat ramps – and any new infestations that might be discovered – while still keeping on top of other invasive species issues, he said.

“With the limited amount of resources that we have, we need to know which sites pose the greatest risk,” Buckley agreed, suggesting that DEP conduct further research into the risk of transmission at various ramps.

“This is a complex problem … we have to be very careful not to rob Peter to pay Paul,” he said.

The amended bill, as proposed by DEP, would also give the warden service more authority to fine boaters who have not purchased the state’s mandatory “milfoil sticker.”

Funds from the sale of the sticker provide most of the revenue for DEP’s invasive aquatic plant programs.

A work session on LD 1723 has been scheduled for the session beginning at 2 p.m. Thursday, Feb. 12, in Room 437 of the State House.