Stricter Idaho invasive-species laws, prompted by detection of invasive quagga mussels in the Middle Snake River near Twin Falls, took effect July 1.

State Department of Agriculture inspectors in late September found a live adult quagga mussel and larvae. A river segment was chemically treated and subsequently monitored until water temperatures fell below spawning thresholds.

No viable mussels have been found since post-treatment monitoring resumed in early June, Nic Zurfluh, Idaho State Department of Agriculture Invasive Species Bureau chief, said July 2. Monitoring, done every two weeks, will continue into October.

Quagga and zebra mussels can cause major damage to irrigation and drinking water systems as well as hydropower plants. They can attach to watercraft and other conveyances and survive transport between water bodies.

The state has been at the forefront of combating invasive species since the legislature created the program in 2008, and now has “additional tools in our fight to protect agriculture, power generation, recreation and private property,” State Department of Agriculture director Chanel Tewalt said in a news release.

Annual sale of stickers affixed to watercraft 10 feet or longer is an established funding source. Senate Bill 1372 provides additional money for the invasive-species program.

The separate SB 1322 requires nonresident owners of watercraft, before launch, to buy a sticker and to have their craft inspected. The state has about 20 inspection stations.

Up to 20% of the invasive species sticker fund’s annual revenue is now available to help cities, counties or other local entities equip and operate inspection stations, according to ISDA.

All conveyances are now subject to new requirements when they are removed from water for transport. Conveyances include boats, sailboats, kayaks, paddle boards, inflatable watercraft, trailers or other means of water transportation.

Operators must remove vegetation and drain all water — including from hulls, ballast tanks, bilges, live wells and motors. Plugs and other barriers must be removed and left open during transport.