Aquatic nuisance species

Some readers may remember hearing about the detection of zebra mussels in the Colorado River in Grand Junction last summer. It may still remain unclear what that means, or why it matters to the Gunnison community. 

Zebra mussels are considered an aquatic nuisance species (ANS), which is exactly what it sounds like: any species that lives in water and causes a problem when introduced to a new area. Zebra mussels are often a poster child for ANS-related messaging. But when we talk about ANS, we mean any and all organisms that threaten our local ecosystem, whether they’re animals, plants or even bacteria.

Why do we care about these species? The mussels have no natural predators here. The same way that deer and elk populations would skyrocket without hunters, the mussels would boom without control. These animals grow on hard surfaces in dense colonies. The dam’s hydropower components would quickly get clogged by these ever-growing concrete-like mats, and it would cost millions each year to clean the equipment. Similarly, infestation causes significant damage to the hulls and internal components of boats, and other personal recreational equipment. Aside from the direct impact on human property, these mussels have a profound effect on the ecosystem, and can disturb water quality and the food web enough to cause major crashes in fish populations (including game fish). Our community infrastructure, local recreation and tourism economy would all be deeply threatened by such an infestation.

The main way that ANS are introduced to new areas is when they’re unintentionally transported by humans. While adult zebra mussels latch on to the hulls or internal components of boats, free-swimming juveniles, known as veligers, can survive for days or weeks in bilges, live wells and engine cooling pipes. There was even a recent incident on Blue Mesa where veligers, which are invisible to the naked eye, were detected in a paddleboard’s carrying case. 

Other ANS infestations throughout the country and the world have taught us that prevention is almost always cheaper and easier than treatment. This is because total eradication is nearly impossible once they’ve been introduced. Sealing the cracks in our “basement” means implementing vigilant measures such as inspections and increasing public awareness.

Such doom and gloom! What’s the upside? What are we doing about it? There are two prongs to that answer. Agencies at the local, state and federal levels are actively working to protect against ANS, and the broader community (you!) has a part to play.

Every two weeks, professionals from Colorado Parks and Wildlife (CPW) and the National Park Service (NPS) collect samples in Blue Mesa, Taylor Reservoir and Lake San Cristobal to ensure any detection can occur early. Boaters will be familiar with the ramp inspection stations operated by CPW. This year, the Park Service is deploying three brand-new self-service mobile stations at high-traffic points along the Taylor and Gunnison rivers, allowing river users to quickly and easily sanitize their own equipment without an inspection official present. Outreach staff will be deployed throughout the basin to increase awareness and assist users with the new stations. The Upper Gunnison River Water Conservancy District is working with Hinsdale County, CPW, and the Park Service to upgrade much-needed infrastructure on Lake San Cristobal, which will aid the inspectors’ abilities to operate. These improvements will come with increased inspection hours and a longer inspection season, allowing more opportunity for public access. 

While policies and enforcement are mostly focused on motorized boaters, anyone moving between water bodies is at risk of transporting ANS. Whether you’re a boat fisher, a paddleboarder or just taking the kids to the beach, there are quick and easy steps we can all take to do our part in protecting our water and our community. Visit stopaquatichitchhikers.org/prevention/ and find the section that most closely describes you. For pet owners, bathe your furry friends thoroughly (including between paw pads) and allow them to dry completely; repeat with vests, leashes or other gear. These guidelines are especially important if you’ve previously been in waters with confirmed ANS presence, or where you don’t know the infestation status.

(Ari Yamaguchi is a water resources specialist at the Upper Gunnison River Water Conservancy District. For more information or questions, contact AYamaguchi@UGRWCD.org.)