7379 - Laserfiche WebLink

Home Browse Search

1042 TYUS TABLE 3. - Water depths and velocities at locations of radio-tagged Colorado squawfish on spawning grounds in the Green and Yarnpa rivers, 1981-1988. Resting-staging includes eddy and pool habitats; deposition-fertilization includes riffle and run habitats with cobble and boulder substrates. Number Number Depth (m) Velocity (mls) River and year offish of contacts' Mean Range Mean Range Resting-staging Green 1982 1 1 1.8 1983 1 1 0.3 .~ 1984 7 301 1.9 0.9-4.1 0.3 0.1-1.1 1985 3 40 4.2 0.6-5.2 0.1 0.1-D.2 1986 0 1987 2 12 2.1 I. 7-2.4 0.2 0.0-0.2 Weighted mean 2.1 0.3 Yampa 1981 7 74 1.8 0.8-2.7 0.4 0.03-1.2 1983 7 46 2.4 1.0--5.8 0.5 0.1-1.5 1984 5 261 1.7 0.8-3.0 0.2 0-0.4 1985 3 77 3.3 0.8-4.3 0.2 0-0.3 1987 4 22 2.0 1.3-2.7 0.1 0.1-D.2 1988 2 8 2.9 2.7-3.0 0.1 O.I-D.l Weighted mean 2.1 0.2 Deposition-fertilization Green 1982 0 0 1983 2 17 1.3 1.2-1.4 0.4 0.4-0.5 1984 7 177 1.0 0.3-1.7 0.6 0.1-1.5 1985 I 3 0.6 0.3 1986 0 1987 2 9 1.1 0.8-1.7 0.8 0.2-1.1 Weighted mean 1.0 0.6 Yampa 1981 7 65 1.2 0.6-1.7 0.6 0.4-1.2 1983 4 21 1.0 0.6-1.2 0.8 0.3-1.0 1984 6 82 0.9 0.6-1.5 0.4 0.1-1.0 1985 I I 1.5 0.2 1988 3 12 0.9 0.5-1.2 0.5 0.2-D.9 Weighted mean 1.0 0.5 · A single contact is one 15-min period of observation. movement patterns of five radio-tagged fish that 21.0oC and 63 m3/s in the Yampa River (Table were tracked to the same spawning area for more 5). than I year. In addition, seven fish were captured The average spawning period began 38.8 d and recaptured on the same spawning ground, and (range, 22-53) after peak discharge in the Yampa no fish was taken on more than one spawning area River and about 37.4 d (range, 21-53) after peak within or between years. flow in the Green River. The length of the time Over the years of the study, migratory radio- interval between peak flow and spawning was neg- tagged fish were present in spawning reaches of atively correlated with the date of peak flow (r = Gray Canyon on dates ranging from June 17 to -0.85, P = 0.07 for the Yampa River; r = 0.98, August 18 and in Yampa Canyon from June 20 P < 0.01 for the Green River); that is, earlier peak to August 17 (Table 4). Ripe fish were also cap- flows were associated with a delay in spawning. tured June II-August 18 in Gray Canyon, and The spawning period was associated with water June 27-August 18 in YampaCanyon. The length temperatures of 190C or more (average low tem- 1- of this "spawning period" (the total period of time perature during the spawning period), but tem- in which migrating or ripe fish were present; Table perature-response correlations were not signifi- 4) ranged from 24 to 57 d. During this time, av- cant for the Green River (r = -0.7, P = 0.19, N erage annual water temperatures and mean flows = 5 years), and data were not available for cal- were 23.40C and 237 m3/s in the Green River and culating a response for the Yampa River.