Abstracts Health Sciences

Colonization and decontamination of quagga mussels in the western United States: Monitoring veligers in Lake Mead and field testing in the effects of hot-water spray as a means of watercraft decontamination

by Sean Robin Comeau

The introduction and establishment of aquatic invasive species (AIS) is one of the top causes of global biodiversity loss and ecological change, and is also financially costly for taxpayers and agencies managing protected areas. This is especially true regarding the nationwide spread of dreissenid mussels to various bodies of freshwater. The discovery of invasive quagga mussels (Dreissena rostriformis bugensis) in Lake Mead on January 6, 2007 has changed the popular recreation area into a potential vector of the destructive AIS. This location could allow for an increased spread of these dressenid species to uninfested bodies of water in the western United States due to overland transport of contaminated watercraft. In order to prevent further infestations, new information must be used to generate and revise uniform minimum protocols and standards for watercraft decontamination programs. Protocols regarding safe and inexpensive procedures, such as hot-water sprays, which result in the 100% mortality of quagga mussels, need to be created. Current protocol regarding zebra mussels may not be applicable to quagga mussels due to an increased susceptibility. Emersed adult quagga mussels were exposed to hot-water sprays at 20, 40, 50, 54, 60, 70, and 80°C for 1, 2, 5, 10, 20, 40, 80, and 160s. Sprays at ≥60°C for 5 s were shown to be 100% lethal. Sprays of 54°C for 10 s, 50°C for 20 s, and 40°C for 40 s also resulted in 100% mortality. A spray temperature of 60°C for 5 s is recommended for mitigating fouling by quagga mussels. Inaccessible areas and areas with special heat requirements on watercraft were also evaluated and field tests on actual quagga encrusted watercraft were performed under summer and winter conditions, respectively. This study also determined veliger abundance and colonization rates during different months of the year, which is helpful for anti-fouling management strategies.