No boats are allowed in parts of Annabessacook Lake in Monmouth and Great Pond — including Great Meadow Stream — in Rome, at least for the time being.

The Maine departments of Environmental Protection and Inland Fisheries and Wildlife have issued a temporary ban on watercrafts in portions of those bodies of water to suppress the growth of variable-leaf milfoil.

The area of surface use restriction on Annabessacook Lake is around the Waugan Road boat launch on the southwest portion of the lake in Monmouth. It restricts all watercraft from using the area, including paddle crafts like kayaks and paddleboards.

The renewed Great Pond and Great Meadow Stream surface use restriction limits only motorized watercrafts. The restricted area includes a portion of North Bay where Great Meadow Stream flows into Great Pond. The restriction is also for Great Meadow Stream.

“The purpose of the restrictions is to reduce fragmentation by closing it off to boats,” said Maine DEP biologist John McPhedran, who is heading the invasive aquatic species program. “We really want to get a big dent in suppressing the infestations and get them back to a level where they can be controlled.”

The 7 Lakes Alliance is working to control the invasion in Great Pond. The DEP has awarded the group a $28,572 grant this year for plant removal work.

A $21,371 grant was also awarded to the Friends of Cobbossee Watershed, Cobbossee Watershed District and Annabessacook Lake Association, which are overseeing the suppression efforts at Annabessacook Lake.

Monmouth selectmen closed the Annabessacook Lake boat launch on Waugan Road in 2018 when approached by the organizations, but this is the first year the DEP and IFW have issued a temporary ban.

Augusta West Kampground in Winthrop is letting the public use its boat ramp to access Annabessacook Lake. A second public boat launch will eventually be built on the lake, according to Monmouth Town Manager Curtis Lunt.

Toni Pied of Friends of the Cobbossee Watershed said that invasion is worrisome because Annabessacook Lake feeds into Cobbosseecontee Lake via Jug Stream. Two other non-native aquatic plants have been discovered in Cobbosseecontee Lake.

“This lights a fire under people to get the (variable-leaf milfoil) spread under control,” Pied said.

Last year, Friends of the Cobbossee Watershed hired New England Milfoil to treat the infestation for six weeks. The company has scuba divers go into the water using a machine that suctions the plant out of the water. The collected plants are either composted or incinerated. This year, the company has been hired for 10 weeks.

It’s too early to tell yet whether last year’s milfoil suppression effort was successful in either waterbody because the lakes are not warm enough for aquatic plants to grow.

Discovering milfoil is a little easier than disposing of it.

Annabessacook Lake Association Director Sue Neal said that volunteers floating in kayaks, canoes and other small watercraft use homemade scopes to peer into the water and see the plants. The scopes are made from buckets with see-through bottoms. It prevents glare, making plant life easier to see. The plant grows where there is adequate sunlight in more shallow water.

“If you can see the ground, you can see if there is milfoil,” Neal said.

Signs warn about milfoil in Annabessacook Lake on Wednesday near the closed boat launch on Waugn Road in Monmouth. Kennebec Journal photo by Joe Phelan

This species of milfoil, however, is one of several in Maine and is native to the southeastern U.S. How variable-leaf milfoil spread into the Annabessacook, Great Pond and Great Meadow Stream isn’t known, but it likely came from boaters who had used their craft in an infected lake.

Boaters visiting these and any Maine lake can control the spread of invasive species. McPhedran stressed that not only is it important to clean a boat after taking it into any water body but to let it dry.

Variable-leaf milfoil spreads quickly and aggressively by autofragmentation, Pied said, when pieces of the plant break off and new plants form. This is why motorboat use is prevented in these sites, McPhedran said, because motor propellers can break up the plants.

It’s not certain how long variable-leaf milfoil remain viable, but one plant was lodged in a boat trailer that had last been in a Wisconsin Lake.

“Could it have grown?” McPhedran asked.

He didn’t know but said that “it was in good enough condition that the species could be identified.”

Pied said that dense outbreaks of milfoil are hard to paddle a kayak through, they can increase water temperature and they can suffocate other plants and limits biodiversity in that ecosystem.

“That’s a good place to grow mosquitoes,” Pied said.

This reduction in recreational value eventually can cause an impact on the housing market. Both Pied and Neal said infestations eventually caused a decrease in shoreline property value on Lake Arrowhead in Limerick and Waterboro.

“People are watching,” said Neal. “People on the lake are very concerned.”