Zebra and Quagga Mussels: Viability of _Dreissenid_ Veligers through our Conveyance Systems and Downstream Rivers
Project ID: 4454
Principal Investigator: Denise Hosler
Research Topic: Invasive Species
Priority Area Assignments: 2010 (Zebra and Quagga Mussels), 2011 (Zebra and Quagga Mussels)
Funded Fiscal Years: 2010
* What factors in conveyance systems and downstream rivers affect the viability and potential for _Dreissenid_ mussels to infest water bodies downstream?
Veligers, the microscopic, larval stage of _Dreissenid_ mussels have been detected in Reclamation reservoirs across the Western United States. and often present an operations and maintenance (O&M) threat. Current Reclamation data indicate that while the _Dreissenid_ mussel has a very high fecundity, high larval populations downstream are not consistent or predictable. The effect of water flow through large conduits, pipes, and canal systems on mussel larvae have not been studied. Reclamation has several examples where the upstream reservoir has very high larval densities; however, the downstream facilities have very different populations. One example of this is at Lake Mohave, Nevada/Arizona, where larval populations are very high eleven months out of the year and the domestic water intakes for the Metropolitan Water District of Southern California (MWD) and the Central Arizona Project (CAP) occur. One system is totally infested with mussels, presenting a serious control issue, and the other does not have large mussel populations. There is speculation on why this occurs, however the cause and effect relationship has not been identified. On the Colorado-Big Thompson Project, Colorado, larvae have been detected in the upper altitude reservoirs, where the water must travel many miles in a conduit system to the lower altitude reservoirs. Testing to date has not confirmed the presence of mussels in the downstream water bodies, and the question of viability of downstream veligers has also been raised.
A combination of optical instruments with a number of viability stains will also be used to determine distinguish live and dead _Dreissenid_ veligers. Understanding the viability of veligers in conveyance systems may provide clues for additional control techniques to reduce the high populations and negative imp
Need and Benefit
_Dreissenid_ mussels have a negative impact to water delivery facilities and structures, and while early detection provides planning time for facility managers, it does not provide predictive information for downstream risks. When _Dreissenid_ mussels are found in Reclamation facilities, the first response is to perform a risk assessment of the facilities to identify potential operation and maintenance (O&M) issues created by their presence. Understanding the downstream viability of veligers, will enhance the value of these assessments, as well as assist in understanding the risk of infestation to downstream facilities. A benefit of this research is that it will provide is a better understanding of the impacts to _Dreissenid_ mussel veliger survival when exposed to the unique water delivery structures in the Western United States Current _Dreissenid_ mussel control strategies are limited, and so the other long term benefit is that it will provide more information about veliger survivability. Understanding the factors that limit veliger survivability then has the potential for determining additional environmental parameters that can be utilized to control then invasive mussels in and downstream of Reclamation facilities.
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