State efforts work to keep Winnipesaukee healthy, but they can't do it alone

GILFORD — An invasive species known as the spiny water flea reached Lake Winnipesaukee in 2023, and the state Department of Environmental Services is doing everything they can to thwart its impact.

Unfortunately, there’s just no “good management” of them.

“You can’t really specifically target them like you can with these other plants. It’s easy with the plants, we can go diving or do a DASH: diver assisted harvesting. You can see the bottom here; it’s easier to go in and pinpoint where they are and just get rid of them that way,” said Georgia Bunnell, Clean Lakes program coordinator for DES. “But it’s harder with these animals that are freely moving.”

During a presentation at the Gilford Islands Association Summer Meeting late last month at Gilford Town Hall, Bunnell reminded residents of what plagues the lake, and what aquatic invasive species to look out for.

Battle of the blooms

Five invasive species pepper parts of Lake Winnipesaukee — the first New Hampshire lake to fall victim to them — with the latest just discovered in 2024. Of these, three are plants, and they include the all-too-familiar variable milfoil, as well as water violet and the brittle/spiny naiad. The two animals include the Chinese mystery snail and the spiny water flea.

Variable milfoil has plagued Winnipesaukee since 1965, affecting all surrounding Lakes Region communities and the aquatic ecosystem as a whole. This aquatic invasive species, or AIS, is transferred via boats and fragmentation, the process of breaking into little pieces. Successful remediation efforts include diving and herbicides.

Hot spots exist today around the lake, including off Smith Cove in Gilford and Welch Island.

Water violet, discovered in 2020 in parts of Meredith, Laconia and Lake Opechee and recognized by its whorled leaves, is known for its popularity in aquariums and backyard ponds and gardens. It’s this popularity that is largely to blame for its appearance in local waters.

“We are not completely certain on how water violet was first introduced in New Hampshire lakes, but we suspect it was done purposefully from an aquarium or water garden of some sort,” Bunnell said. “Since being introduced, it is believed that it has been spreading accidentally by waterfowl/wildlife.”

Newer than the water violet is the brittle naiad, also known as spiny naiad, found in Moultonborough last year. Nearshore areas and portions of Winnipesaukee with shallow water are prime habitats for this AIS, and the naiad's serrated “tooth-like” leaf edges differentiate it from its native sibling. The brittle naiad is something residents should be concerned about.

“That’s why we [DES] are really jumping on the water violet and the naiad, so it doesn’t get as widespread as milfoil,” Bunnell said. “That’s why it’s really important to detect early.”

The remaining AIS found throughout the Big Lake — the Chinese mystery snail — remains, well, a mystery.

There is no definitive date marking its arrival to Winnipesaukee, but it was most likely sometime in the 1900s, since the snail was discovered near Boston in 1915. The snail devours zooplankton, outcompeting native species for both food and habitat, resulting in their diminishment.

But no one really knows how the snail arrived here, and there’s no real way to thwart their presence.

“If someone comes across them, we recommend throwing them out. Either in the trash if possible, or discarding them somewhere outside as far as possible from the lake,” Bunnell said.

‘The nuisance infection’

As the saying goes, the best defense is a good offense.

That starts with educating residents and lake enthusiasts about Lake Winnipesaukee’s five invasive species, what they look like, and how to properly remediate them.

Luckily, DES staff make it easy to identify species prior to filing an official report, thanks to their Weed Watcher volunteer program, which comes with a thorough identification workbook featuring color photos.

“The Weed Watcher kits come with a clipboard and all these files that show how bladderwort compares to milfoil,” among other examples, said Bunnell.

Bladderwort does resemble milfoil, with many folks often mixing up the two. Variable milfoil has what Bunnell describes as a “squirrel tail” — it’s thick and fluffy — and a bright red stem. Bladderwort lacks a root system, whereas milfoil has one.

The Weed Watcher program is a small time commitment for volunteers, only requiring a waterbody survey done once a month throughout the summer months, May through September. Volunteers can enjoy a lackadaisical trip (or two) around the lake while simultaneously preserving its health.

If a volunteer boats upon an AIS and successfully identifies it, the specimen is then photographed (and sometimes sent) to DES for further instruction. If it’s truly an invasive, DES staff will “formulate a plan of action to control the nuisance infection.”

It’s what they specialize in, after all.

Bunnell’s sole priority in her role is invasive species — watching them, tracking them and ridding New Hampshire’s waterbodies of them.

Because it is illegal to sell, distribute or transport certain aquatic plants, Bunnell’s team has disseminated a list of what not to stock in stores or sell.

“My interns have been visiting different pet stores/aquarium centers to inspect what aquatic plants they are selling in order to make sure they are not in violation of this law. This is one way the Exotic Species Program works to stop the spread of invasives,” Bunnell said.

Of course, cyanobacteria is at the forefront of everyone’s mind as blooms continue to be reported on Lake Winnipesaukee. While not an invasive species, cyanobacteria is a major concern.

If you think you’ve observed a cyanobacteria bloom, take advantage of the Bloom Report Form at des.nh.gov/water/healthy-swimming/harmful-algal-blooms. The form provides photo examples of blooms and encourages individuals to upload their own photos, as well as provide pertinent details for the state.

Completed reports “are sent in real time to Michele Busi, the interim harmful algal bloom coordinator, who will then determine if the information and photos are legitimate, and issue a warning or watch if appropriate. All of the information provided by whoever reported the bloom is then posted onto the Healthy Swimming Mapper, including date, location, and photos,” Bunnell explained.

Access the Healthy Swimming Mapper at des.nh.gov/water/healthy-swimming/healthy-swimming-mapper.

And while there is an indirect correlation between milfoil and cyanobacteria, there are certainly some curiosities.

Bunnell thinks it relates to the impact on nutrient cycling and the overall ecosystem.

“We have a lot more milfoil in our lakes, which is more organic material essentially, and eventually that organic material will die off after the growing season. That winds up decaying, putting more nutrients into the [water] system.

“Those nutrients can then be taken up again by plants later during the next growing season, and kind of create a cycle,” she said.

The spiny water flea loves these nutrients, completing a full “circle of life" moment. With all hands on deck in the pursuit of lake health, abatement can be a reality.

“Even just educating other people on what these plants look like, or even these animals like the Chinese snail,” Bunnell said. “People [need to] know what to look for and why it’s important to observe and manage these different species.

For more information on aquatic invasive species and how to become a Weed Watcher volunteer, visit des.nh.gov/home-and-recreation/boating-and-fishing/invasive-species.