|New Mexico Fish and Wildlife Conservation Office biologists net Rio Grande silvery minnow. Photo by USFWS|
Stewart Jacks, Assistant Regional Director of Fisheries in our Southwest Region talks about the no-longer-quite-so-grand Rio Grande and our work to conserve this New Mexican fish.
If you need a reminder that the Earth is held together by stone, look to the Sandia and Manzano mountains in central New Mexico. Born of what must have been violent tremors, the Rio Grande slices down a natural rift left behind by massive movements of whole plates of planet Earth that birthed these mountains. Where the southern Rockies end, these new and different mountains emerge. From Placitas to El Paso the west face of a long chain of dry crags reveal the past.
In these tilted wedges, the remains of sea-dwelling creatures swim forever entombed in limestone 10,000 feet above sea level. Along this front of friable mountains, few people live. Night skies are inky black and you feel you can still reach out and touch the cosmos rarely concealed by clouds. No clouds—no rain. The sky governs fate in the American Southwest.
The Rio Grande, as grand as it is, is not the river it once was. Despite the remoteness and sparse population, the river has been thoroughly humanized by command of its water. Rio Bravo del Norte, as the river is called in Mexico, has lost its bravado. It is wild and turbulent no more. A river that once flushed with spring snowmelt and summer freshets—pulses of water that told native minnows ”it’s time to spawn”—has been weakened by manmade structures.
A river wide and braided that carved new paths under its own power, as rivers are in the habit of doing, is now rather oddly perched above its own floodplain through long reaches. Under the summer heat, sun and sand may soak it up leaving cakes of mud and pools soon to pass. Fresh sodden spring sediment rich with ripe cottonwood seeds that regenerate mosaics of riparian woodlands are historic artifacts as prickly water-sucking non-native trees now dominate the depleted river’s rigid course.