7834

• UCREFRP Catalog Number: 7834
• Author: Burdick, B. D. a. R. B. B.
• Title: Experimental Stocking Of Adult Razorback Sucker In The Upper Colorado And Gunnison Rivers.
• USFW Year: 1997.
• USFW - Doc Type: \
• Copyright Material: NO

1994 & 1995 GUNNISON RIVER RZ RADIOTELEMETRY
DISPLACEMENT
.112
.130
N .170
.320
.380
.390
i .400
' .410
.440
.? .460
} .470
V .480
Z .502
W .520
.560
Q .600
W .640
.660
U. .680
O .700
.740
Q .760
Q .780
.800
.820
UPSTREAM
DOWNSTREAM
n=23
1994: April-August
1995: March-October
Data
20 15 10 5 O 20 40 60 80
RIVER MILES
Figure 6. Total maximum upstream and downstream displacement (from
release point: '0' on the X-axis) for 25 radiotagged adult
razorback sucker monitored between March and September 1994
and March and September 1995 in the Gunnison River, Colorado.
Note: the upstream scale is one-fourth that of the downstream
scale.
At the end of the study, 3 fish were confirmed alive, 3 were missing, 2
were confirmed dead, and 17 were presumed dead. Nine radiotags were recovered,
the first on 5 May, the last on 23 August 1994. As with fish stocked in the
Upper Colorado River, mortality of razorback sucker stocked in the Gunnison River
in 1994 did not appear to be immediate but delayed following release. Post-
stocking survival was low for fish stocked in the Gunnison River during 1994 and
1995: confi rmed mortal i ty was 8%; actual mortal i ty mi ght have been as hi gh as 88%
if missing and presumed dead fish were included.
San Juan River
One concern when stocking fish in large rivers is the vast downstream
displacement that usually follows release. Movement data from pond-reared
razorback sucker released in the Upper Colorado and Gunnison rivers indicates
that the majority of downstream displacement occurs within the first few weeks
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