ABSTRACT
Quaggamussel veligers were present year round. Average veliger numbers from March 2007 to March 2008 were 6.6/L in Boulder Basin, 0.7/L in Overton Arm, 0.3/L in Temple Bar of the Middle of Lake Mead, and 0.04/L in Gregg Basin in upper Lake Mead. In Boulder Basin, veligers peaked in summer (July) and fall (October) of 2007, while in the middle of this reservoir, only one peak was found and there was no peak in the upper Lake Mead. The results of the veliger analyses demonstrated that adult mussels were established in Boulder Basin, but not in the upper lake. This matches the result of abundance and distribution of adults and juveniles.
