Taos Field Office conducts fish population survey in the Rio Grande del Norte National Monument

BLM Fisheries Biologist Cody McLean with one of the largest Brown trout fishes caught during the survey.
BLM Fisheries Biologist Cody McLean with one of the largest Brown trout fishes caught during the survey.

In early June, BLM New Mexico Taos Field Office Lead Fisheries Biologist Sage Dunn and Fisheries Biologist Cody McLean successfully planned and completed a fish population survey on the Ute Mountain section of the Rio Grande River within the Rio Grande del Norte National Monument in New Mexico. Conducting a fish population survey on this stretch of the Rio Grande is an arduous endeavor, requiring a 25-mile, three-day float, and ending with hiking all boats and gear up 300 feet to the rim of the Rio Grande Gorge.

BLM staff and volunteers, along with two students and a teacher from the Bosque School, float in their rafts and inflatable kayaks as they depart from the Lobatos Bridge in Colorado.
BLM staff and volunteers, along with two students and a teacher from the Bosque School, float in their rafts and inflatable kayaks as they depart from the Lobatos Bridge in Colorado.

Pulling off this survey requires impeccable timing and cooperation from staff office-wide and outside partners; because of these challenges, this survey has not been conducted since 2010. Due to the density of nesting raptors in the Upper Rio Grande Gorge, the earliest this survey can be undertaken is June 1, when springtime flows have begun to subside and, in many years, when the river is already too low to navigate. The trip is also logistically complex, requiring many hands to help hike out gear and shuttle vehicles. The trip also depends upon the availability of a New Mexico Department of Game and Fish fisheries biologist.

BLM Fisheries Biologist Sage Dunn and New Mexico Department of Game and Fish Fisheries Biologist Taylor Booth rig the electrofishing raft at the put-in.
BLM Fisheries Biologist Sage Dunn and New Mexico Department of Game and Fish Fisheries Biologist Taylor Booth rig the electrofishing raft at the put-in.

This year everything fell into place, with flows above the minimum required 400 cubic-feet-per-second, allowing the team to navigate the large rafts down the river. Also on hand were staff from the river program, along with resource staff and a New Mexico Department of Game and Fish fisheries biologist. In addition, two students and a teacher from the Bosque School in Albuquerque, New Mexico joined the trip to collect samples for their own studies.

Team members process fish caught in one of the mile-long survey reaches.
Team members process fish caught in one of the mile-long survey reaches.

The team launched at Lobatos Bridge in Colorado, floating nine miles down to New Mexico and sampling the first reach right at the state line. Sampling consists of rowing the shocking raft down the mile-long survey reaches with two netters in the front of the raft. The netters work on netting stunned fish and keeping them in a live well until the end of the reach, where the fish are weighed, measured, and released. Six one-mile-long reaches were sampled in this stretch of the Rio Grande River. Participants caught Brown and Rainbow trout, in addition to native species such as the Rio Grande Chub, which is a BLM Special Status Species.

Team members process fish caught in one of the mile-long survey reaches.
Team members process fish caught in one of the mile-long survey reaches.

At the end of the float, everyone banded together for the daunting task of hiking rafts, frames, inflatable kayaks, and other gear out of the gorge at Cow Patty and Lee Trails. Both trails are relatively short but boast steep inclines and large boulders. Many hands made short work and the team carried all equipment out safely.

A special thanks goes to the Taos Field Office managers, who allowed their staff members to divert from their day jobs in order to help facilitate this important survey.

Story by:

Cody McLean, Fisheries Biologist

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