Freshwater Jellyfish in Smith Lake
Posted: 24 Aug 2009 06:12 AM PDT
Kathy Potocsnak called me recently about a mystery organism that she'd found near her boat dock on Smith Lake. Since I couldn't recognize it from a verbal description, she brought one to the office. I made some photos and sent them to Rusty Wright, Extension Fisheries Specialist. Here's his response:"Yep that is a freshwater jellyfish. I usually get 1-2 calls a year confirming the presence of these critters in our lakes and ponds. I think many times I'm settling a bet! "Freshwater jellyfish, Craspedacusta sowerbyi, is a non-native species originally from Asia. It is now common virtually globally. They eat small zooplankton but there is no evidence that they do any damage to our ecosystems. People see them most often from clear lakes, pools, and reservoirs: however they are also in more cloudy turbid water as well it is just that we can't see them as well in those systems. "It is an interesting critter!"Here's a link to the U. S. Geological Survey's web page about these jellyfish.This jellyfish was actively swimming around in the jar. It swim throught the water for a few seconds, then it would pause and just float. After I made these photos, Kathy took the jellyfish back to the lake.Thanks to Rusty for the identification of the photos, and to Kathy for bringing the freshwater jellyfish to our office.