When I lived by the Great Lakes, whenever my family went boating we were always concerned about Zebra Mussels attaching to our boat. These little buggers get about as big as your fingernails, but lay anywhere from 100,000 to 500,000 eggs per year. Native to Eastern Europe and Western Russia, these mussels spread very quickly and can cause a lot of problems for humans and water-dwellers alike. They clog engines, and swarm shores and docks. More importantly, they can attach to larger muscles, killing them, and in excessive populations, their plankton feeding can starve larval fish and kill off populations, impacting the food chain.on plankton. They were first discovered in the Great lakes in 1988 and there is little that can be done to reduce their population. If you’re ever boating in the Great Lakes region, check your boat to make sure it’s not carrying any stow-aways!