Progress / Science

Aquatic Invasive Species Management Update: Zebra Mussel and Spiny Waterflea Monitoring

The aquatic invasive species (AIS) management team has been busy all summer—and with good reason. The ever-present threat of AIS spread has kept the team hard at work, sampling, surveying, and monitoring lakes across the state. But what exactly is it that we are doing? Though there are many intriguing facets to our summer field work, I would like to give you a glimpse into just one: statewide monitoring for the spread of zebra mussel and spiny waterflea.

Seeing the words “zebra mussel” and “spread” in the same sentence may sound an alarm bell in some people’s heads. But rest assured, as of 2016, we have had no indication of new zebra mussel introductions, nor have there been any new spiny waterflea introductions. So what’s the big deal? Why have we already invested dozens of hours this summer to zebra mussel and spiny waterflea monitoring and plan on even more? Well, it starts with Lake Champlain. As we all know, Lake Champlain is home to several aquatic invasive species. Of the aquatic invasive animal species found in the lake, zebra mussels are arguably the most pervasive and problematic. It is hard these days to find any hard surface in Lake Champlain that isn’t covered with the quarter-sized bivalves. And for decades now, zebra mussels have been the sworn enemy of all bare feet that enter the lake. The spiny waterflea, a new invader to Lake Champlain as of 2015, holds potential to create a whole new suite of problems for native species and lake users alike. Spiny waterflea disrupt the natural food web by outcompeting native zooplankton, the base of the aquatic food web. Furthermore, the tiny crustaceans have a long tail barb that easily becomes tangled in fishing tackle, making trolling for lake trout and salmon quite difficult.

Based on the slew of problems created by these two species in Lake Champlain, it would be a travesty to see the same issues appear in our inland waterbodies. That’s where we come in. Though spread prevention may be the best means of AIS control, early detection is critical to inform our spread prevention efforts—and we have been vigilant. Since 2015, the AIS management team has been collecting water samples from lakes that are at high risk of invasion by zebra mussel and spiny waterflea. The water samples are brought to our lab in Montpelier and analyzed for presence of zebra mussel veligers, the microscopic larval stage of the animal, and spiny waterflea, which are also small and easy to miss with the naked eye.

Each year, our monitoring program has become broader and more defined. In 2015, water samples were collected from the public boat accesses of twenty-five waterbodies. The following year, the number of lakes was expanded to 26, and samples were collected at the boat access, inlet, and outlet of each waterbody. In 2017, we plan to expand the number of lakes and ponds sampled to 37, and these samples will be analyzed later this fall.

Though our team has been working tirelessly to monitor the spread of these species, it is nearly impossible to prevent it without the help of Vermont boaters. The surest way for any boater to prevent the spread of zebra mussel and spiny waterflea is to adhere to the guidelines of Clean, Drain & Dry before moving from one waterbody to another. Just like aquatic invasive plants, zebra mussel and spiny waterflea can be transported by boats. Zebra mussel veligers can attach to the hull of boats that have been sitting in an infested water. Both zebra mussel veligers and spiny waterflea can survive in small amounts of standing water in interior compartments, such as live wells, as well as in the motor’s intake. Wherever possible, boaters should take advantage of the boat wash stations scattered throughout the state. A heated power wash, livewell flush, and motor flush are the best ways to ensure no zebra mussels or spiny waterflea have hitched a ride on a vessel. When a boat wash station is unavailable, cleaning equipment and draining the vessel, and letting both dry in the sun for 10 days is recommended. By following these steps, anyone can do his or her part in the fight against aquatic invasive species.

For a list of waterbodies sampled in 2016, follow this link.

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Aquatic Invasive Species Intern, Caleb Basa, using a plankton tow net to collect samples on Waterbury Reservoir. The samples will be analyzed for presence of zebra mussel veligers and spiny waterflea later this fall.