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<br />2000 COLORADO PIKEMINNOW IN WHITE RIVER
<br />strength, and aircraft speed). From September
<br />1992 to April 1993 (before placing any upstream
<br />of the dam), we monitored fish locations month-
<br />ly and approximately weekly between 15 April
<br />and 30 September 1993. Fish locations during
<br />1994 were monitored in late April and on 2
<br />dates during the migration and spawning
<br />period (1 and 13 July). Although radio-track-
<br />ing was not monitored on a continuous basis,
<br />travel rates (km d-I) were calculated for each
<br />fish for the 1993 migration period.
<br />RESULTS
<br />Twelve Colorado pikeminnow (409-743 mm
<br />TL, 1000750 g) were captured in the 0.4-km
<br />taihvater reach below Taylor Draw Dam (km
<br />168.2) in 1992 and 1993 (Table 1). The 6 fish
<br />(#1-6) captured and implanted with radio
<br />transmitters in September 1992 remained in
<br />the White River within 1 km below Taylor
<br />Draw Dam through fall 1992 and spring 1993
<br />(Fig. 2): The 6 fish (#7-12) captured in April
<br />1993 were located within a 0.8-km reach
<br />below the dam. It was assumed that all fish
<br />survived because each transmitter remained
<br />active throughout the 2-yr monitoring period.
<br />The spawning migration of these fish was
<br />extensive. Colorado pikeminnow tagged in the
<br />White River migrated an average of 658 km
<br />from the White River to spawning sites in the
<br />Yampa or Green rivers and back to the White
<br />River (Table 1, Fig. 2). All 12 radio-tagged fish
<br />migrated downstream in the White River in
<br />1993 and entered the Creen River. Seven of
<br />these fish moved upstream in the Green River,
<br />5 fish (#1, 3, 8, 9, 10) into the Yampa River
<br />spawning area (Yampa Canyon km 0~2), and
<br />2 (#2, 7) located 11 and 16 km downstream
<br />of the spawning area (Fig. 2). These 7 fish
<br />mi~*rated between 548 and 951 km from mid-
<br />Jlav through late October 1993. During the
<br />same year 1 fish (#12) moved downstream in
<br />the Green River and .vas located at the Green
<br />Ri~-er spawning site (Gray/Desolation Canyon
<br />km 232-256). Four other fish (#4, 5, 6, 11)
<br />were found 27-1001.zn upstream of the spawn-
<br />ing area (Fig. 2). The Green River migrants
<br />h-a~-eled between 437 and 687 km from mid-
<br />~1av through late September 1993 (Table 1).
<br />All fish returned to the White River between
<br />mid-August and late October 1993, thus show-
<br />ing home-range fidelity.
<br />19
<br />The 8 fish (#1, 4, 7, 8, 9, 10, 11, 12) relo-
<br />cated in the White River (km 198.2) above
<br />Kenney Reservoir in the spring of 1993
<br />remained in historic riverine habitats above
<br />the reservoir until initiation of the down-
<br />stream spawning migration (Fig. 3). One fish
<br />(#1) moved downstream on May 15 (Table 1),
<br />the others between mid-June and early July
<br />(Fig. 2).
<br />On 9 and 14 September 1993, two fish (#4,
<br />9, respectively) were relocated to the lower
<br />end of Kenney Reservoir (km 170.6). These
<br />fish moved upstream of the reservoir (Fig. 3)
<br />within 8 d and were located in historical river-
<br />ine habitats the following spring (20 April
<br />1994).
<br />Five fish (#1, 3, 6, 10, 12) were located just
<br />below Taylor Draw Dam (km 167.4-168.2) and
<br />2 fish (#4, 9) above the dam (krn 180.2-185.1)
<br />the following year on 20 April 1994 (Fig. 2).
<br />The 5 fish below the dam, located 3-15 km
<br />downstream of the dam the previous October,
<br />moved back upstream to the dam in spring
<br />1994. The 2 fish relocated into Kenney Reser-
<br />voir in September 1993 moved an additional
<br />5-8 km further upstream. On 1 and 13 July
<br />1994 seven fish (#1, 2, 3, 7, 8, 9, 10) located in
<br />April were found within the Yampa River
<br />spawning reach: three (#5, 6, 12) were found
<br />at the Green River spawning site, and two
<br />(#4, 11) were found between 43 and 105 km
<br />upstream of the Green River site. All fish
<br />moved to or near the same spawning area they
<br />used the previous year.
<br />The 12 fish traveled an average of 6 km d-I
<br />(range: 4-10 km d-I) during the migration
<br />period from May through October 1993 (Table
<br />1). Generally, fish moved faster to the spawn-
<br />ingsite than back to the White River.
<br />Aside from their spawning migration, these
<br />fish moved very little within their home ranges
<br />in the White River. For example, the 6 fish
<br />tagged in 1992 moved only 0.1-2.3 km in the
<br />tailwater reach below Taylor Draw Dam from
<br />September 1992 through April 1993. All 12
<br />fish, after migrating to and from their respec-
<br />tive spawning sites, migrated back to the
<br />White River by late August and September
<br />1993. Five of these fish (#1, 4, 6, 9, 11) moved
<br />back upstream to Taylor Draw Dam and then
<br />redistributed themselves downstream 2.4-10.1
<br />km by October 1993. The other 7 fish (#2, 3,
<br />5, 7, 8, 10, 12) did not appear to move up to
<br />
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