Heading out to Pomleau Island on North Pond

During the North Pond Association’s Annual Pike Derby on February 15, our Invasive Aquatics team hit the ice for two reasons: to share Clean, Drain, Dry practices with anglers and to check on curly-leaf pondweed (CLP) under the ice.

Year-Round Threat

Even in winter, aquatic invasive species can spread. Plant fragments and reproductive structures (like CLP turions) can hitchhike on augers, sleds, traps, boots, and fishing gear. When anglers move between waterbodies without cleaning and drying equipment, they can unknowingly transport invasive species to new lakes. That’s why Clean, Drain, Dry isn’t just for summer boaters — it’s essential year-round.

Monitoring Hot Spots

Most derby participants were fishing in deeper water, away from known CLP hotspot areas. We, however, headed straight for those hotspots. Using GPS coordinates from last season — areas where dense patches had produced turions (the plant’s reproductive structures) — we bored five test holes to evaluate how effective our targeted SCUBA removals were.

Captain Mann drilling holes

Curly-leaf pondweed is a cold-water species with a unique life cycle. It grows slowly under the ice, accelerates rapidly after ice-out, and typically peaks in June. By getting an early start in spring, CLP captures sunlight and nutrients before many native plants emerge from dormancy. This competitive advantage allows it to form dense mats that reduce biodiversity and alter freshwater habitats.

Some native pondweeds, like towering large-leaf pondweed (Potamogeton amplifolius) and low-growing fern-leaf pondweed (Potamogeton robbinsii), remain hardy in deeper water through the winter and are often mistaken for curly-leaf pondweed.

Large-leaf pondweed beds are the “kelp forests” of our freshwater lakes — providing important vertical habitat for fish and other wildlife while creating stunning underwater structure. Fern-leaf pondweed, by contrast, grows low and dense along the lake bottom, forming horizontal coverage that stabilizes sediments and improves water clarity by reducing turbidity.

Good News

We found no curly-leaf pondweed in any of the five holes. That’s an encouraging sign that last season’s targeted removals significantly reduced density in those areas. We are counting down the days till we get to see all our underwater friends this spring!