Juvenile Quagga Mussels have been detected in Nevada lakes located only an hour from Lake Tahoe, and while the immediate threat to other lakes isn’t entirely clear, the danger seems real (via the Reno Gazette):
Juvenile mussels are present in Lahontan Reservoir while Rye Patch Reservoir remains “suspect” for their presence, a new round of tests indicates.
There is no evidence adult mussels are thriving or reproducing in either water body but the danger of that possibility must be taken into account as boating activity is managed across the region, officials said.
The juvenile Quagga mussels in question are small enough to avoid detection by the naked eye, and in fact, a recently released Colorado State University report details the difficulty (click here to read the .pdf for yourself):
Unfortunately for boaters and boat inspectors, dreissenid mussels are microscopic during their larval, planktonic life stage. Dreissenid mussels at this stage of development are called veligers, and typically range in size from 50 to 400 μm (Ackerman et al. 1994). At this size, they are nearly invisible to the naked eye, and unlikely to be detected during a boat inspection. Very small spaces containing a small amount of water could also contain veligers and potentially facilitate colonization of new waters, if the veligers survive the pre-launch period.
Inspections might prove useful for some invasives, but for others, it’s clear that angler and boater education — and the development of clear-cut disinfection procedures — are needed to manage invasives across multiple bodies of water.