Spiny Waterflea: A growing threat to New Hampshire Lakes

The invasive spiny waterflea has been found in three New Hampshire lakes, including Winnipesaukee, Winnisquam, and, most recently, Newfound Lake. While it has not yet been detected in Squam, its spread nearby is cause for concern.

Native to Europe and Asia, the spiny waterflea likely arrived in the U.S. through ballast water from cargo ships. It is a tiny crustacean with a long tail spine that can tangle in fishing lines and gear, making it easy to spread between lakes.

Though harmless to humans, this invasive species disrupts lake ecosystems by eating native zooplankton, which form the foundation of the aquatic food web. As native plankton populations decline, water can become murkier, algae and cyanobacteria blooms may increase, and young fish lose an important food source. Once established, spiny waterfleas are nearly impossible to remove.

Prevention is key

You can help keep Squam free of spiny waterfleas by following these simple steps every time you move between lakes:

• Clean boats, trailers, and gear with hot water or a mild bleach solution.
• Drain all water from boats, live wells, and equipment.
• Dry gear completely before visiting another waterbody. Six hours of drying is usually enough to kill eggs.

Every clean boat and careful angler helps protect Squam Lake from this invasive threat. We are actively monitoring the situation and working on outreach and education programs to help prevent the spiny waterflea from entering Squam Lake.