Take a Minute. Save a Million.

By: Josh Neff – Eastern Regional Coordinator, FLI Watercraft Steward Program

As the temperature rises heading into the “dog days” of summer, so is the activity at boat launches across the Finger Lakes region. Boat launches are a known hot spot for introductions of invasive species due to the overland dispersal of “hitchhikers” or fragments of plant and animal matter that attach to either the watercraft or trailer used to haul the watercraft. With each launch of a boat, there is the potential for a new species to be introduced into that body of water. Watercraft stewards (WSPs) are stationed at boat launches across the Finger Lakes region to offer voluntary inspections and educate boaters on the potential transport and effects of aquatic invasive species, so that invasions can be prevented. After all, prevention is the best management strategy because it is efficient and low-cost (see invasion curve, Figure 1). One of the main reasons prevention is such an effective management strategy is due to the time frame involved with prevention when compared to eradication efforts. Eradicating an invasion that has already been established can take anywhere from weeks to years, if possible at all. When stewards perform inspections, prevention can take just a couple of minutes.

Figure 1. The invasion curve depicts the control costs of eradicating a species that has invaded an ecosystem. Prevention can occur before a species has invaded an area, which minimizes the control costs and has the greatest chance of successful management.

Recently at Emerson Park on Owasco Lake, a Jet Ski was preparing to launch when a Finger Lakes Institute watercraft steward, Garrett Boleslav, offered the boater an inspection to search for invasive species. After a thorough visual check there was no sign of anything concerning, but while feeling underneath the Jet Ski in areas out of Garrett’s view, he was met with a poke from a sharp barb. Caught in the grate of the Jet Ski’s water intake (Figure 2) was a nutlet from the prohibited water chestnut (Trapa natans) (Figure 3). If not for Garrett’s valiant effort, this nutlet could have found a new home in Owasco Lake for the summer. During a staff bi-weekly meeting, Garrett brought his findings to the rest of our WSP staff, and shared his strategy and method for finding the nutlet with his peers.

Figure 2. In order to power the Jet Ski, water must be sucked into the watercraft to spin an impeller, which is then shot out of the back end of the Jet Ski to provide power. The grates are designed to block any large debris from entering the watercraft’s propulsion system. These grates, as demonstrated by Garrett Boleslav, can sometimes catch debris from the water, and hold onto it after the watercraft leaves the water.
Figure 3. The water chestnuts found by Garret Boleslav (left) and Huntter Smith (right). Notice the sharp barbs, which allow the nutlets to easily attach to clothing, exposed skin, recreational gear, and fishing gear.

A few days later, on the 4th of July, traditionally one of the busiest days of the summer at boat launches,  watercraft steward Huntter Smith also intercepted a water chestnut nutlet while conducting an inspection on Cayuga Lake. To the untrained eye, it would be difficult to notice a nutlet caught to the felt bunk of a trailer, but to Huntter, it was part of his inspection process that every boater should partake in before launching, or after retrieving their watercraft.  

The one nutlet that Garrett or Huntter removed could have potentially turned into 25 plants the next season, and so on for years until proper treatment takes place. One acre of water chestnut is capable of turning into 100 acres the next season (Minnesota Sea Grant 2016). Due to the floating nature of water chestnut, they nearly block out all sunlight with their dense mats, which prevents native plant communities from growing underneath causing decreased oxygen for fish. In order to control water chestnut, a significant amount of time, personpower, and money has to be used for control projects. Hand pulling and mechanical harvesting of water chestnut costs hundreds of thousands of dollars per year, and millions by the time projects are complete. Just for some perspective, agencies have collectively spent over $13 million dollars on just water chestnut control efforts in Lake Champlain over a 36 year period (Vermont Department of Environmental Conservation, 2018)! So, next time you are launching a watercraft, take a minute to inspect your boat for hitchhikers and it could save millions of dollars in ecological, economic, and human health damages. Kudos to Garrett, Huntter and the other stewards for a job well done, and a thank you for protecting our beautiful Finger Lakes!

Sources:

Minnesota Sea Grant, 2016, Water chestnut (Trapa natans). [Online]. Available at http://www.seagrant.umn.edu/ais/waterchestnut.

Vermont Department of Environmental Conservation. 2018. Water chestnut Harvest Program 2017. [Online]. Available at https://dec.vermont.gov/sites/dec/files/wsm/lakes/ans/docs/2017%20VT%20WC%20hand%20harvesting%20report.pdf).

http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/protecting-victoria

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