7617

• UCREFRP Catalog Number: 7617
• Author: Platania, S. P. and K. R. Bestgen.
• Title: Survey of the Fishes of the Lower San Juan River, New Mexico.
• USFW Year: 1987.
• USFW - Doc Type: Albuquerque, New Mexico.
• Copyright Material: NO

taken at all stations. Speckled dace were the most abundant
native species collected, and the fourth most common species
collected overall. It was distributed throughout the study area
and was found at 23 of 25 sites. The native bluehead and
flannelmouth suckers ranked fifth and sixth, respectively, in
overall abundance and were also found throughout the study area.
Collectively, the six aforementioned species comprised 99.5% of
the backwater collections.
Other native species were rare. The mottled sculpin was
collected sporadically with electrofishing gear in the San Juan
River above Shiprock, but was not taken in the seine samples
analyzed. Roundtail chub were collected from three stations
(single YOY specimens from each site) in October. A few YOY
specimens from the unsorted August seine collections were noted
during cursory field examination, but overall, roundtail.chub of
any size appeared to be rare in the study area. During the
August survey, we collected YOY roundtail chub in the Mancos
River, about 1 km upstream of its confluence with the San Juan
River. Roundtail chub was taken from both connected and isolated
backwaters. Depths varied from < 0.3 m - > 2 m. Substrate
composition was variable (silt to cobble) and water temperatures
ranged from 13-170 C.
Single YOY Colorado squawfish were collected from two
backwaters, one 3.0 river miles above the Mancos River and the
other 0.5 river miles below, during the October survey.
Specimens are currently being verified at the Larval Fish
Laboratory, Colorado State University, Fort Collins. Although no
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