Presentation: Hitchhikers in Our Lake!

Speaker: Dr J Shannon Swan, PhD, RS, REHP


Lake Mead National Recreation Area is a startling contrast of desert and water, mountains and canyons. However; on an unseasonably warm January day in 2007, Qugga mussels were discovered on a boat line which was being pulled from Lake Mead. From that fateful day to this, the way visitors look at Lake Mead has changed.


Qugga mussels found in Lake Mead National Recreation Area in January 2007 pose a growing and permanent menace to fish, boaters and the health of lakes in the west! Once they are here there's no way of getting rid of them.


Since the building of Hoover Dam in 1933 Lake Mead was not only the largest man-made lake; it was the most pristine.


Qugga mussels began appearing in the Great Lakes in the early 1900s from ballast water. Scientists now know they outcompeted the zeber mussels their smaller cousins.


A qugga mussel is about the size of a fingernail, and one qugga mussel can filter a liter of water per day. They clear water by filtering phytoplankton, but their waste products accumulate on the lake floor nourishing algae. Anytime an invasive species is taking food out of the water column, which is both what both the qugga and zebra mussels are doing--you then are taking food from something else. This could be a total ecosystem changer!


Through research, we have learned that qugga mussels are more troublesome than zebras because they can move, including to water treatment and power plant intakes. This has already imposed a huge economic impact on the Federal Government and the boat owners.


The qugga muscle is small -- about 20 centimeters. With 6 breeding seasons per year can generate up to a million microscopic larvae in a year. The qugga has no dormant period and feeds all year long, using up food sources for native fish and affecting the natural food chain, often creating an overgrowth of algae.


The qugga mussel also is believed to be the culprit that caused the "dead Zone" in Lake Erie, by exuding phosphorus and eliminating oxygen in the water, killing fish and plants.

Quggas can live in deeper colder water than the zebra mussels and use less energy and release mobile larvae.


On the up side, state officials believe that the infestation of qugga muscles in the western waterways may be the key for getting federal dollars for more and improved sewer systems.


Learning Objectives:


         Know the dynamics of the qugga mussels reproduction rates.

         Discover how they can foul sewer and water intake lines which supply services to the Las Vegas Valley.

         Are Qugga killing off the small population of zeber mussels?

         What, if anything, can we do to stop the spread of these invasive mussels?

         Will all bodies of water in the west be doomed by these unwanted Hitchhikers?