Clearer water means high quality water, right? Well, not necessarily. Take Lake Mead as an example, where clearing water is actually evidence of the impact of the quagga mussel. This mollusk was introduced to the Great Lakes from Ukraine in the 1980s and was first discovered in Lake Mead in 2007, and as an invasive species, its impact in considerable. The quagga is a filter feeder, which means that it clears small detritus from the water. The species consumes plankton and algae that make up the base of the aquatic food web. Increased clarity of water makes fish more susceptible to predation, reducing the effectiveness of natural camouflage. Increased light penetration results in changes to plant and algae growth patterns, thereby altering the natural environment.
With no natural predators, the quagga mussel might go unchecked were it not for the efforts of land management agencies. The Great Basin Institute and the National Park Service are collaborating to combat the effects of the quagga and other invasive species at Lake Mead. Unfortunately, methods to eradicate the quagga remain elusive, but work can be done to limit spread of the mussel to other bodies of water. What this comes down to is monitoring, lake user surveys, inspections of boats and ramps, and, most importantly, educational outreach. GBI and NPS Aquatic Invasive Species Outreach team have made extensive efforts to reach as many visitors to the Lake Mead Recreation Area as possible with information about how to reduce the spread of quagga. This is particularly important for boaters, as water craft that have not been decontaminated are the primary means of invasive dispersion. In the past, this outreach has been limited to summer months, but now GBI and NPS have upped their efforts, creating a fall outreach team to educate off season visitors and to observe winter visitor patterns at launch ramps.