7379

• UCREFRP Catalog Number: 7379
• Author: Tyus, H. M.
• Title: Potamodromy and Reproduction of Colorado Squawfish in the Green River Basin, Colorado and Utah
• USFW Year: 1990
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

1040

near both spawning areas: Warm Springs in Yam-
pa River (RK 7.2) and Aorence Creek in Green
River (RK 253). Although Warm Springs was at
the downstream end of the spawning area, many
fish that migrated downstream in the Yampa Riv-
er were tracked there early in the spawning period,
but they later returned to more upstream loca-
tions. All downstream migrants enroute to the
Gray Canyon site passed the mouth of Aorence
Creek. In addition, there were numerous areas of
groundwater seepage from canyon walls into the
river in or near both spawning areas (RK 16.5,
17.6, 19.8 in the Yampa River; RK 233.3,249.6,
250.4 in the Green River).
Seventeen fish in the Green River that were
classified as suspected migrants displayed move-
ments (average, 99.5 km; range, 35.2-384 km)
during the same time that other fish undertook
spawning migrations. Of these, 12 moved to Split
Mountain and 5 to Labyrinth Canyons. It is un-
known whether these fish were strays enroute else-
where (to Yampa Canyon in case of fish located
in Split Mountain, to the Colorado River for fish
in Labyrinth Canyon), or spawned at sites in these
canyons. One fish moving to Labyrinth Canyon
was later tracked by airplane to Cataract Canyon
ofthe Colorado River during the spawning season.
Five Colorado squawfish that were radio-tracked
to spawning grounds in more than 1 year dis-
played similar migratory patterns each year. Three
fish migrated downstream to Gray Canyon, and
two migrated downstream to Yampa Canyon.
None of the five migrated to more than one
spawning area within a year, or to different areas
in different years; that is, fish tracked to one
spawning ground established a migratory pattern
that was consistent for each year it was tracked.
We recaptured 204 Carlin-tagged Colorado
squawfish that had been tagged by various work-
ers; 170 recaptures were of 149 fish among the
981 fish that we tagged (recapture rate, 15%). An
additional 13 fish were captured with a Carlin tag
line attached, but no tag. Total recaptures includ-
ed 30 recaptures of 21 radio-tagged fish. These fish
were recognized both by tag and by the old wound
from the surgical implant; however, seven tags
had been lost from these fish (23% tag loss). Fifty-
seven fish (25%) were captured (and recaptured
elsewhere) or recaptured in one of the identified
spawning reaches.
Colorado squawfish were recaptured in Gray
Canyon from I to 7 years after tagging, and moved
an average of 169 km downstream (N = 24) and
73 km upstream (N = 4) to reach the Gray Canyon

TYUS

spawning area. These recaptures included two fish
that were recaptured there in two consecutive years,
one recaptured from the Yampa River (a distance
of 456 km), two from the White River (294.4 and
304 km), and two from the Duchesne River (147.2
and 168 km). In addition, one fish tagged in Gray
Canyon was recaptured in Cataract Canyon of the
Colorado River (267 km) and one was captured
in the Dirty Devil River (326 km).
Thirty-one Colorado squawfish were recaptured
in the Yampa Canyon 1-3 years after tagging. Of
these, 18 were tagged in the upper Yampa River
(distances of59.2-195.2 km), 7 in the Green River
(46.4-251.2 km), I in the White River (372.8 km);
5 fish were recaptures that were originally tagged
in the spawning reach.
Many fish were recaptured one or more times
within 16 km of their initial capture in spring and
autumn. Twenty-three fish in the Green and 4 in
the Yampa rivers that were at large for 1-4 years
were tagged and later recaptured in April and May;
4 fish in the Yampa River were tagged and recap-
tured in September and October, and 15 fish in
the Green and 2 in the Yampa rivers were tagged,
recaptured, or both in spring and autumn after 1-
4 years. Fifty fish were recaptured within one
month of tagging.
Remaining recaptures (N = 39) had moved 20-
315 km from their initial capture point; however,
little or no apparent reason for these movements
could be determined from the limited recapture
data. Among these fish were 19 of juvenile size
(<435 mm TL, the length ofthe smallest ripe fish
captured), which were recaptured after 1-5 years.
Fifteen adults were previously reported above as
recaptured within a year or two after tagging; little
movement by these was detected, except for one
that moved to Lake Powell and three that mi-
grated to known spawning areas. The remaining
five adults moved an average 182 km (range, 22-
331) in the next 1-3 years. Three of these five fish
moved upstream in the Green River, one moved
up in the Green and into the Yampa River, and
one fish in the Yampa River moved further up-
stream.

Reproduction
In total, 308 Colorado squawfish were captured
in the spawning reaches of Gray and Yampa can-
yons (Table 2). Ripe fish included 14 females (one
ripe female was found dead on a sand bar) and
194 males. All ripe fish were captured on the
spawning areas except one ripe, radio-tagged male
that was recaptured about 40 km from the Yampa

~

,-

to