Now that the 2014 Lake Champlain Monitoring Report is available online, we can report it contains bad news about the spread of spiny water flea.
While we knew the spiny water flea would travel fast once introduced, the extent to which it spread through Lake Champlain in 2014 surprised us. The first sighting, near Valcour Island, was reported on July 22nd. Then, on August 27th, one spiny water flea appeared in a sample taken at a long-term monitoring site. More were found in September samples, and by late October spiny water fleas were present in samples from 12 of 14 long-term monitoring sites.
Based on stories from other states, the arrival of the spiny water flea is bad news. In Wisconsin, for example, spiny water fleas eat native Daphnia pulicaria, small crustaceans that eat algae. According to University of Wisconsin aquatic ecologist Jake Vander Zanden,“Since the spiny water flea invasion, Lake Mendota has seen a 95% reduction in D. pulicaria abundance and, in turn, a one-meter decrease in Secchi depth.” In other words, Lake Mendota’s water clarity decreased as algae growth increased. This is especially bad news for Vermont, as Wisconsin’s experience suggests spiny water flea could exacerbate the problem of excess algae growth caused by high phosphorus levels in Lake Champlain.
What can we do? Ann Bove, aquatic invasive species management specialist with the Vermont Lakes & Ponds Program, reports the only known management strategy for spiny water flea is spread prevention. We cannot halt its spread in Lake Champlain, but we can keep it out of other lakes. To learn how, visit the “Stop Aquatic Hitchhikers” website.
For additional information about the spiny water flea (Bythotrephes longimanus) see this National Park Service Fact Sheet. More information about invasive species in Vermont is available on our website.