Invasive mussels found in Arizona lake

Discovery of adult quagga mussel at Canyon Lake could impact recreational and municipal water users

PHOENIX -- In mid-December of 2015, personnel from the Arizona Game and Fish Department's Aquatic Invasive Species (AIS) Program positively identified an adult quagga mussel attached to the hull of a boat recently removed from Canyon Lake, a major recreational lake on the Tonto National Forest.

Previous sampling conducted at Canyon Lake in October and November produced evidence of the genetic presence of quagga mussels near Mormon Flat Dam.  Microscopic analysis of the October and November samples yielded a total of two veligers (quagga larvae). The findings suggest for the first time that quagga mussels are able to survive and reproduce in the lake.

Due to these discoveries, AZGFD will be ramping up its monitoring efforts at Canyon Lake and Saguaro Lake. In addition, the Department will classify Canyon Lake as an  AIS-affected water under AIS Directors Orders #2. Because Apache Lake is interconnected through a pump-back water system, and Saguaro Lake, the lower Salt River to Granite Reef Dam, the Salt River Project Canal Systems, and Tempe Town Lake are connected by moving water downstream, the Department and partners might also be classifying those waters as AIS-affected.

In addition, AZGFD will expedite plans to utilize 2016 federal AIS grant money to add personnel in the Mesa region and to purchase several mobile watercraft decontamination units. This will aid in assisting the public to “clean, drain and dry” – and especially decontaminate – their watercraft and equipment prior to exiting this area of the Salt River chain of lakes. These increased efforts are necessary to curtail the advancement of this highly invasive species to other waters in central Arizona and the rest of the state.

Quagga mussels colonize rapidly on hard surfaces and can ruin recreational watercraft motors, alter water quality for aquatic wildlife, and clog water intake structures such as pipes and screens, thereby impacting pumping capabilities for power and water treatment plants.

“The Department recognizes that finding one adult quagga mussel and indications of reproduction do not mean total infestation at the lake,” said Tom McMahon, AZGFD aquatic invasive species program coordinator. “But all recreationists and boaters need to remember to clean, drain and dry their watercraft and equipment after every use to minimize the looming threat of a full-blown infestation in this system, and perhaps statewide.”

Under Arizona law, boaters and all recreationists who take watercraft and other equipment out of waters designated as having aquatic invasive species must use the following steps when leaving that listed water:

• CLEAN. Clean/remove any clinging material such as plants, animals and mud from the anchor, boat, motor, hull, trailer, etc.
• DRAIN. Remove all water drainage plugs (and keep them out during transport). Drain the water from the bilge, live-well and any other compartments that could hold water. Drain the water from the engine and engine cooling system(s). You can do this by lowering the outboard, while on the ramp, until the water is removed.
• DRY. Ensure the watercraft, vehicle, equipment, or conveyance is allowed to dry completely before placing in another water in Arizona. Leaving your plugs out during transport will assist in ventilating and speeding the drying time of those difficult-to-dry areas of your boat.

For more information on quagga mussels, including the Director’s Orders lists of aquatic invasive species, waters, and statewide decontamination protocols, visit https://www.azgfd.com/Fishing/InvasiveSpecies. If you are in need of decontaminating your moored boat before transporting from an AIS-affected water, please contact AZGFD at (623) 236-7608.