7612 ‎(2)‎

• UCREFRP Catalog Number: 7612
• Author: Roberts, B. and M. Moretti.
• Title: Final Fisheries Survey of the San Juan River, Utah 1988.
• USFW Year: 1988.
• USFW - Doc Type: Salt Lake City, Utah.
• Copyright Material: NO

electrofishing, effort was directed at areas judged most likely to harbor rare
fishes. Additional target sampling was conducted in the river and in an adjacent
irrigation pond at RMI 92.0. BLM records (BLM 1981) show that razorback suckers
were collected from the pond in 1976. Catch rates were not calculated from
additional target electrofishing data.

Piute Farms Netting

Four trammel nets were set near the boat 1 aunch at Pi ute Farms where
razorback suckers were collected in the spring of 1987 by the BaR. Trammel nets
were 300 ft long x 12 ft deep with 2 3/4 inch inner mesh wall and 12 inch outer
tangle netting. Nets were set perpendicular to the sh9reline shortly after
sunri se, checked and reset around noon, and pull ed before darkness . All
razorback suckers, both initial captures and recaptures from 1987, were measured
to the nearest mm (total length) and weighed (+1- 20g). All new razorback
suckers were marked with a numbered blue Carlin tag. Fish were released unharmed
in an adjacent bay. Other species of fish were counted and released.

Canyon NettinQ

Various habitat types in the canyon areas between Comb Wash (RMI 80) and
Government Rapids (RMI 23) were sampled extensively with trammel nets between
8 July and 20 August 1988. Sampling efforts concentrated on back eddy type
habitats along rock faces and below rapids. Four sampling trips were taken: 8-
11 July, 16-22 July, 3-8 August and 17-21 August. The first two trips
concentrated on the canyon reach between Comb Wash and Ledge Rapids (RMI 80-66),
while the canyon reach between Mendenhall Loop and Government Rapids (RMI 56-
23) were sampled during the two August trips. Trammel nets were 75 ft or 50 ft
long x 6 ft deep with 1 inch mesh wall and 12 inch outer tangle netting. Nets
were set with motorized 16 ft zodiac raft upon arrival at a sampling site (i.e.,
early afternoon). The 50 ft nets were generally set in smaller back eddies where
the longer nets would not fit. Nets were checked twice before darkness and once
the following morning when pulled. Nets not catching fish were pulled and reset
in new locations. Each location was considered a sample regardless of the amount
of time each net fished. During times of possible floods events, nets were
pulled prior to darkness. Hours fished were recorded for each sample and catch
rates of all fish species were calculated.

YounQ-of-the-Year SeininQ

Standardized young-of-the-year (yay) sampling was conducted between mid-
August and mi d-September. Young-of-the-year sei ni ng was conducted on two
different trips: 18-21 August (RMI 50-5) and 12-16 September (RMI 135-0). The
August trip was in conjunction with a canyon netting trip. Seines used in yay
sampling were 15 ft long x 4 ft high with 1/8 inch ace-mesh. Two seine hauls
were made through each backwater. The first of two seine hauls, typically
covered the deepest part of the backwater. Only backwaters of approximately 30
m2 or greater surface area were seined. Seine hauls were made across the long
axis of the backwater from shore to shore whenever possible. When the backwater

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