First we found the New Zealand Mud Snail in Lake Shasta; now we’re faced with the news that Zebra mussels — the scourge of the Great Lakes — have been found in a Hollister area reservoir (Hollister’s located south of the San Francisco Bay Area).

Zebra Mussels cover every available surface in very high densities and can precipitate huge declines in fish populations by altering the biomass.

If you want to see what Zebra Mussels can do to a boat hull, click here.

(Found via the excellent California Water Blog: Aquafornia)