¿Qué hay abajo

¿Qué hay abajo? Mejor no muevas ni un mejillón.

It’s a question that hits harder after one of the driest, harshest winters in the last thirty years. You look at the Eagle River, the water line receded by the lack of snowpack, and you assume the danger is just the thirst of the land itself. But there’s a warmth to the shallows now, a vulnerability that goes beyond drought. Hidden just beneath the surface, where the water is low and slow, are other threats. They aren’t waiting for you to notice; they’re already there, waiting to disrupt the balance of the river you fish, swim, and drink from.

Colorado Parks and Wildlife (CPW) has been tracking these aquatic nuisance species for years, defining them not just as plants or animals, but as any non-native organism that damages lakes, reservoirs, rivers, and streams. This includes viruses and parasites that cause disease in fish, organisms that alter the ecological balance and, once established, permanently affect recreational, commercial, and agricultural uses of the water. In Colorado, the impact stretches beyond environmental damage. These species threaten native wildlife, public health, property values, and local economies. They spread unintentionally through recreational activities and the gear used in the water, displacing native species and altering the health of our rivers. As water levels drop and river systems become more vulnerable, the risks they pose increase.

The state has taken this threat seriously. The Colorado Aquatic Nuisance Species Act, signed into law in May 2008, prohibits possessing, importing, exporting, transporting, releasing, or introducing these species into the state’s waters. It authorizes trained officers to inspect boats and, when necessary, disinfect them or place them in quarantine to prevent the spread of invasive organisms. But even the strictest policies fail without public participation. Protecting our rivers depends on the actions of those who use them. Residents and visitors alike play a fundamental role in preventing the spread of invasive aquatic species between watersheds. The effectiveness of state programs depends directly on community support. Staying informed, taking simple preventive measures, and sharing knowledge are some of the most powerful tools for protecting our waters.

So, what is hiding below? Four invasive aquatic species are particularly concerning for the rivers and streams of Eagle County. Zebra mussels and Quagga mussels are among the most problematic, alongside New Zealand mud snails and “rock snot” (Didymo). Each presents unique risks, but they all share a common face: they thrive in the disturbed, low-water conditions that characterize our current landscape. You can feel the tension in the water when you look closely. The mussels, in particular, are a major problem in Colorado, filtering out native plankton and starving out the fish that depend on them. They attach to hard surfaces, clogging pipes and weighing down boats, turning a clear river into a crowded, choking ecosystem.

The message from CPW is clear. It’s not just about the water level; it’s about what’s in it. When you launch your boat, when you wade into the Eagle, when you pack your gear, you are moving these invisible passengers. The law is there, the officers are ready, but the first line of defense is you. It’s about knowing what to look for, what to clean, and what to leave behind. The river is changing, and the creatures below are changing with it. If you don’t move a single mussel, you might just keep the balance. But if you do, you could be the one spreading the next crisis. The water is low, the sun is bright, and the invaders are waiting.