Impact of Quagga Introduction on Reservoir Water Quality
Quagga mussels, since their appearance in the Colorado River system over the past several years, have quickly come to dominate much of the available habitat in the main reservoirs, and even many portions of the Colorado River itself. Once their populations reach high levels, they are known to be effective at altering food webs, as demonstrated in the Great Lakes, through their efficient selective filtering of the water column.
While their impacts to the Great Lakes are becoming better documented, Western reservoirs represent a very different type of ecosystem, especially given the fact that these are manmade systems. Good predictions can be made from other studies about changes in water clarity and overall production, which can then be linked to water quality issues and potentially significant changes in the fishery.
We have a good idea of when quagga mussels made their appearance in Lake Mead, and analyses of this unique long-term data set should allow us to identify the specific impacts quagga mussels have had on the reservoir community. This information would significantly help advance the science of understanding the consequences of this species as it spreads to other areas.
Need and Benefit
There are few studies, especially in the West, where there exist good, long-term, limnological data sets of the quality that is present at Lake Mead. Further, this is the first Reclamation system to have been invaded, and now dominated, by the presence of quagga mussels. Analyzing this dataset to determine if changes have occurred over time to the Lake Mead ecosystem will provide valuable insight as to what might be expected to occur should this species successfully colonize other Reclamation facilities.