7288

• UCREFRP Catalog Number: 7288
• Author: McKay, T. S.
• Title: Razorback Sucker Capture and Transport in Lake Powell, April 1990.
• USFW Year: 1990.
• USFW - Doc Type: \
• Copyright Material: NO

aerator was used to transport fish to the Ouray Experimental Fish
Propagation Facility. Lake water (13.5 °C) was loaded into the tank
with a centrifugal pump and salt (0.5~ NaCl) and furacin (5 ppm)
were added.
Incidental mortalities (2 males, SJA) were frozen on dry ice after
removing duplicate samples of gonad, heart, liver, kidney and
muscle tissue. Duplicate milt samples were also taken from one of
the deceased fish.
Maps used for distance measurements, capture location coordinates
and noting net placements in the field were USGS 7.5 minute series
topographic maps. Those covering the sampled area in the San Juan
arm included: No Mans Mesa North, Mikes Mesa, Nokai Dome and
Monitor Butte. The Hite North quad covered all of the sampled area
in the Dirty Devil arm. Map distances were measured with a Minerva
curvimeter.
RESULTS. San Juan Arm
Netting in the San Juan arm commenced on April 3 and terminated
during the morning of April 6. A total of 122.6 net hours were
expended in this area, and fourteen razorback suckers were captured
(Table 1). Two fish (males) died before transport and 1 (female)
escaped after a nighttime windstorm lposed the live pen from its
shoreline tethers.
Four of the fish captured had been previously tagged. Three were
marked with large blue Carlin tags, and only thread remained on the
fourth. One of the mortalities was previously tagged # 00,060. UDWR
records show that this fish was originally marked at Paiute Farms
marina by BOR biologists on April 30, 1987. Marked fish # 00,069
was also captured in 1987 by BOR biologists at Paiute Farms marina
in April of 1987. Marked fish # 00,097 was captured by BOR
biologists in April of 1987 at Paiute Farms Marina and again at the
same location in 1988 by UDWR biologists.
Razorbacks were captured close to shore (often only 2 or 3 feet
from dry land) in 13 - 20 °C water 1 to 4 feet deep over rocky
substrates consisting of a mixture of small boulders, cobble,
rubble and gravel in a silty matrix. Macrohabitat consisted of
gradually sloping shorelines, shallow bays and rocky shoals. Water
quality in areas of capture was under very little if any influence
of inflow water. Some turbidity in capture areas was a result of
wind and wave action over shallow shoreline rather than reservoir
inflow.
Netting efforts began at the inflow area of the San Juan River 2.8
miles downstream of the old Paiute Farms Marina boat ramps where
flow was very evident. Capture rates for fish of any species were
low in this area and problems with deep silt and floating debris
prompted a change of location. At 1990 reservoir levels, the inflow
area occurred in a narrow canyon section with steep banks. Nets