A few things will excite any member of the University of Michigan Biological Station, regardless of age or scientific background. Ice cream night, for instance. Volleyball matches. Spotting the aurora over South Fishtail Bay.
A local encounter during week six of the summer 2015 term added another to the list: freshwater jellyfish. Two area hikers found the jellies (Craspedacusta sowerbii) in the north bay of Burt Lake on Thursday, August 6. Camp has been absolutely buzzing with talk of them. Now, they’re in a fish tank in the UMBS office, complete with an aerator and two jugs of lake water to keep them going.
The freshwater jellies are technically an invasive species. Most literature cites them as being from the Yangtze River basin in China, but some sources link them back to the Amazon. They look very much like ocean jellyfish commonly seen in aquariums and documentaries, like something from a miniature version of Finding Nemo. But they’re small and won’t sting powerfully enough for humans to feel. These cnidarians are only about the size of a penny, almost-translucent white, and have little stringy tentacles hanging down from their bell-shaped bodies. They prefer calm water with abundant zooplankton to eat, and tend to be spotted in late summer and early fall. Aside from this, their numbers and appearance are relatively unpredictable. According to a fact sheet from the USGS for nonindigenous aquatic species, several years may go by before another bloom is seen again.
Fortunately for students, faculty, staff, camp kids, and anyone else in the area, these jellies should live on for another three or so weeks, happily floating in their tank at UMBS.