My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
9305
CWCB
>
UCREFRP
>
Public
>
9305
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/14/2009 5:02:34 PM
Creation date
5/22/2009 7:25:06 PM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
9305
Author
U.S. Fish and Wildlife Service.
Title
Final Biological Opinion for the Operation of Flaming Gorge Dam.
USFW Year
1992.
USFW - Doc Type
Denver, CO.
Copyright Material
NO
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
129
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
12 <br />Migration <br />The initiation of spawning migration is an important component of the <br />reproductive cycle of the Colorado squawfish. Based on radio-tracking data <br />(Wick et al. 1983; Tyus and McAda 1984; Tyus .1990), fish in the Green and <br />Yampa Rivers initiated spawning migrations around•,.the super solstice; Green <br />River fish initiated migrations about June 21 (range: May 23-July 22) and <br />Yampa River fish migrated about June 15 (range: May 26-Jul'y 13). These <br />movements included downstream migrations in the Yampa and White Rivers and <br />upstream and downstream migrations in the Green River (Tyus et al. 1987; <br />Tyus 1990). <br />Flows and water temperatures were highly variable during Colorado squawfish <br />spawning migrations, and migrations were initiated earlier in low-water years <br />(e.g., 1981) and later in higher water years (e.g., 1983). The earlier the <br />spring peak flow occurred, the longer the interval before migration began <br />(Tyus 1990). Initiation of spring migration occurred about 28 days after peak <br />flow in the Yampa and Green Rivers (Tyus and Karp 1989). Migration was <br />associated with water temperatures of at least 9 °C (average 14 °C). <br />Homing behavior in Colorado squawfish is suggested by long-distance movement <br />patterns and repeated recaptures of the same fish on spawning grounds in <br />subsequent years (Wick et al. 1983; Tyus 1985 and 1990). Fish use of more <br />than one spawning area was not detected (Tyus 1990), supporting the idea of <br />spawning fidelity in Colorado squawfish. Colorado squawfish spawning areas <br />thus should be protected as unique habitats that are essential to the <br />conservation of the species. <br />The migrations and homing behavior of Colorado squawfish mandates protection <br />of known migration routes. Migrations of Colorado squawfish are vulnerable to <br />stream blockage (Tyus 1984) as evidenced by the recent loss of 50 miles of <br />occupied habitat in the White River due to blockage (Martinez 1986) at Kenny <br />Reservoir. Lack of access to spawning grounds was implicated in the decline <br />of Colorado squawfish (Joseph et al. 1977; Tyus 1984). <br />Soawnina <br />Males generally mature at age 5 or 6 and females at age 6 or 1 (Hamman 1981b; <br />Vanicek and Kramer 1969; Seethaler 1979). Most mature fish in the Green and <br />Yampa Rivers migrate in spring to two locations identified as spawning areas. <br />These include riffle and pool habitats in Yampa Canyon on the lower Yampa <br />River and Gray Canyon on the Green River (Tyus and Karp 1989; Tyus.1990). <br />The annual spawning period (as indicated by the presence of migrating radio- <br />tagged fish on spawning grounds, collections of ripe fish, or calculated dates <br />of larval emergence in spawning reaches) lasts about 4 to 5 weeks. An optimum <br />spawning period also was calculated by averaging the dates in which radio- <br />tagged fish and ripe fish were present in the spawning reach and back- <br />calculated dates of egg deposition. The length of the estimated optimal <br />spawning period (about 26 days) was similar in both spawning areas for all <br />years. Spawning generally occurred earlier in low-water years (1981, 1987, <br />and 1988) and later in high-flow years (1983 and 1984). Discharge was <br />
The URL can be used to link to this page
Your browser does not support the video tag.