How long have they been in the lake?
New research from MAISRC is shedding light on the invasion history of spiny waterflea in Minnesota lakes. Results from a two-year study on Lake Mille Lacs and Lake Kabetogama are showing that spiny waterflea were present in the lakes for decades before they were detected in the water column.
Researchers used dated lake-sediment cores to reconstruct long-term ecological histories. Thanks to their namesake spine, spiny waterflea are very well-preserved in lake sediment. This allows researchers to study food web dynamics, when they were first present, their population growth trajectories, and their impacts on prey.
Cores from both lakes provide evidence that spiny waterflea were in the lakes as early as the 1970s. Their presence was reported in Lake Mille Lacs in 2009 and Lake Kabetogama in 2007.
Knowing that spiny waterflea can exist and persist in a lake for several years before the population is large enough to be detected emphasizes the importance of cleaning and sanitizing all watercraft to prevent the spread of AIS – even if no invasive species have been found in the water body. (A separate MAISRC research project is evaluating the highest-risk types of equipment for spiny waterflea spread in order to prioritize cleaning efforts.)
This research also helps give managers a clearer understanding of the magnitude of the problem posed by spiny waterflea and helps define threats to sport fishing, water quality, and the overall food web. Spiny waterflea is an invasive zooplankton that devastates the food webs of invaded lakes by consuming large numbers of native zooplankton. There are currently 66 waterbodies infested with spiny waterflea, per the Minnesota DNR. Learn more about this research on our website.