Tuesday, October 07, 2014

Rio Grande SIlvery Minnow

Interactive version: http://www.usbr.gov/tsc/rivers/awards/Nm2/rg/riog/schematic/SCHEMATICalbuquerquediv.html

The River. Like the Nile it rises in distant mountains, then flows down through farm, city, farm, and city, losing water to the desert. I've skipped over headwater steams in the highest alpine meadows in Colorado, and fished tributaries from the high peaks in the Wiemenuche, the San Juan, the Sangre de Christo mountains.

The Grande enters New Mexico as a whitewater river cut deep in a thousand-foot canyon, opens onto the agricultural floodplain of the (NM) Central Valley just north of Albuquerque and loses water continuously as it flows south toward Texas and Mexico.

It goes dry most years these days, fish left out under the oven sky. Agricultural diversions, cities. Dams and reservoirs. Water sinking into deep sand. Low-flow channels carry the remaining trickle south to satisfy more cities, interstate treaties. Fought over by water managers, farmers, and conservationists. (Link to article: How much water used by cottonwoods versus farmers versus cities. )

We went seining for fishes: white suckers, red shiners, catfish, chad and fathead minnows but most of all: Silvery Minnows, endemic to New Mexico and listed as Federally Endangered.

The Silvery Minnow is endangered for a range of reasons. Like many river fish it is negatively impacted by dams turning the river into lakes. The drying of the Rio Grande is probably more extensive now than it was before modern agricultural irrigation and pumping, but the Rio Grande probably always went dry and only remained wet in refugia...

Silvery Minnows: One thread in the tapestry of life. We were looking for silver needles in the full force of river water, the gush and rush, one and a half feet per second. We splashed into the surging river water, waded out to the river’s sand bars. We used bag and beach seines, color-coded buckets, rite-in-the-rain and water-resistant-(but susceptible) electronics, but the fish were nowhere to be found.

Mud flats held the first tiny dicotyledons of new weeds, sprouting. In a few isolated backwaters (I can’t say exactly where) we did find a few, or even many, Silvery Minnows, alive and wide-eyed. We photographed them, weighed and measured them, and checked whether they were tagged fish raised in a hatchery or a wild child, conceived in good ol’ mother nature.

For unknown reasons, the 2013 spawning was a good year for the Minnow and it seemed like it might bounce back then, but not much has been seen of that cohort since. Meanwhile, the lawyers aren't waiting .... (link to Wild Earth Guardians lawsuit)

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