By Jeff Cowen, TRPA As the Lake Tahoe boating and paddling season wraps up, agencies leading the Lake Tahoe Aquatic Invasive Species (AIS) program are tallying up the 2024 watercraft inspection season and taking stock of the growing threat of AIS in the Tahoe Region. The Tahoe Regional Planning Agency (TRPA) and the Tahoe Resource Conservation District (Tahoe RCD), which manage the watercraft inspection program, reported Friday that staff inspected over 5,600 vessels since January and intercepted 59 vessels with AIS on board. Though this is an increase from the 46 vessels found with AIS in 2023, it is nowhere near the record of 129 vessels in 2021. Boaters, paddlers, anglers, and beachgoers all help lower the risk of AIS by following the Clean, Drain, and Dry protocol. 2024 by the Numbers 5,600 motorized vessels inspected 59 vessels intercepted with AIS on board 17 intercepts with quagga or zebra mussels 60% of boats arrived Clean, Drained, and Dry 5,200 rover interactions with electric and non-motorized recreators 500 new Tahoe Keepers 900 uses of free CD3 machine Since 2008 118,000 watercraft inspected 7,500 Tahoe Keepers certified Since the program’s inception in 2008, trained watercraft inspectors have cleared 118,000 boats to launch, safeguarding native species and habitat, as well as Lake Tahoe’s famous clarity. Among the vessels intercepted with AIS this year, 17 were found with quagga or zebra mussels, a devastating species that has never been detected in Lake Tahoe. Inspectors are kept informed of regional high-risk waterbodies and trained to screen for all non-native species, including invasive golden mussels that were detected in the Bay-Delta near Stockton in October of this year. “We are fortunate to have a comprehensive inspection program at Tahoe, but it takes everyone working together to protect our waters from the damage that invasive species can inflict,” said Dennis Zabaglo, AIS program manager at TRPA. “With the recent discovery of New Zealand mudsnails in Lake Tahoe and golden mussels in the Bay-Delta, we must stay vigilant and ensure existing protocols will continue to prevent the spread of any mussel into the Lake Tahoe Region.” If vessels are not Clean, Drain, Dry or if a boat has a ballast system like a ski or wake boat, it will undergo a decontamination process. This year, boaters continued to do their part, as 59 percent of motorized vessels arrived Clean, Drain, and Dry. How Things Changed: New Zealand Mudsnails The discovery of invasive New Zealand mudsnails on the South Shore of Lake Tahoe in 2023 prompted TRPA and Tahoe RCD to enact an award-winning rapid response plan to contain the new invasives and keep them from spreading to other lakes and other areas of Lake Tahoe. In addition to Clean, Drain, and Dry, the AIS program emphasized the mantra “Spill Where You Fill” to prevent the movement of New Zealand mudsnails around Lake Tahoe via ballast water or fish wells. New procedures at boat ramps require boaters to drain water, remove vegetation, and examine anchors and line upon exit from Lake Tahoe. Expanding Reach to the Beach This summer, the Watercraft Inspection Program piloted the “Roving Inspector Program” to expand outreach beyond inspection stations to Lake Tahoe beaches and Fallen Leaf and Echo Lakes. Thanks to funding by the Tahoe Fund, roving inspectors interacted with more than 5,200 non-motorized recreators, from families with inflatables to kite surfers, and inspected 100 vessels to emphasize the importance of following Clean, Drain, and Dry protocols. Chris Killian, AIS program manager at Tahoe RCD extolled the progress and potential of the rover program. “We are always looking for ways to reach more recreators, and the rovers were vital in providing information for this growing population,” Killian said. Non-motorized recreators can also become certified as Tahoe Keepers to Clean, Drain, and Dry their own gear. Since the detection of New Zealand mudsnails, over 500 new individuals have registered as Tahoe Keepers. Additionally, innovative waterless cleaning stations called CD3 machines were positioned at popular beaches and available for free use. One CD3 machine at Meeks Bay was funded by the Bipartisan Infrastructure Law, and the League to Save Lake Tahoe funded a mobile CD3 machine. The two solar-powered machines logged over 900 uses this summer and will return to beaches next spring. For more information on how to protect Lake Tahoe from aquatic invasive species, visit tahoeboatinspections.com.