Help STOP THE SPREAD of New Zealand Mudsnails!

City of Boulder Open Space and Mountain Parks has CLOSED South Boulder Creek from South Boulder Road to Marshall road, approximately 2 miles of South Boulder Creek.

New Zealand Mudsnails have recently been discovered in South Boulder Creek upstream of South Boulder Road. This invasive aquatic species negatively impacts local fish populations and disrupts ecological food webs by displacing native macroinvertebrates. What’s the Problem? • They’re tiny! o Adults are about the size of a grain of rice and immature snails are even smaller See image below.• They’re clingy!  Because they’re so small, they can sneak aboard almost anything including waders, boots, and tackle. If it can carry a sand grain, it can carry a mudsnail. • They’re hardy! o NZMS can survive out of water for days • It only takes one! o NZMS reproduce asexually so a single mudsnail can result in a colony of 40 million snails in just one year. • They’re tenacious! o Once they establish in a creek, it’s practically impossible to get rid of them. • They’re bad news! o NZMS can achieve densities of over 70,000 snails per square foot. They displace native aquatic invertebrates (which fish eat) and pass through fish digestive systems without being digested. Ultimately this can result in reduced growth rates and lower populations of fish.

What can anglers do? 

  • Please avoid entering infested waterbodies.
  • Should you inadvertently enter an infested area: Before you leave the field: § Clean your gear of mud/vegetation with a wire brush, o Back at home, do one of the following: § Freeze your gear overnight § Soak gear in hot water (at least 140°) for at least 10 minutes § Submerge gear in 1:1 solution of water and Formula 409® for at least 10 minutes (Note: simply spraying gear with disinfectant does not work) § Thoroughly dry your gear for at least 48 hours, preferably in direct sunlight For more information, please see Colorado Parks and Wildlife’s New Zealand Mudsnail page: https://cpw.state.co.us/aboutus/Pages/ISP-NZ-Mudsnail.aspx