9438

• UCREFRP Catalog Number: 9438
• Author: Clarkson, R. W. and M. R. Childs
• Title: Temperature Effects of Hypolimnial-Release Dams on Early Life Stages of Colorado River Basin Big-River Fishes
• USFW Year: 2000
• USFW - Doc Type: Copeia
• Copyright Material: YES

408 COPEIA, 2000, NO.2
TABLE 1. MULTIPLE COMPARISONS OF LENGTH AND WEIGHT MEAN RANKS (POOLED REPLICATES) ACROSS THREE
TEMPERATURES OF THREE AGES (7, 14, AND 41 DAYS POSTHATCH AT INITIATION OF EXPERIMENT) OF EARLy LIFE
STAGE Xyrauchen texanus. Day is days past initiation of experiment. Superscript denotes comparisons that were
not significant (0. > 0.05) when adjusted for multiple comparisons.
Length Mean Ranks Weight Mean Ranks
Age Day 10 C I4C 20 C IOC 14 C 20 C N
7 8 19.58a 23.80a 48.13 20.95a 20.80a 49.75 60
15 18.63a 22.38a 50.50 13.90a 27. lOa 50.50 60
29 10.50 3U3 49.88 10.50 31. 70 49.30 60
57 10.55 30.45 10.50 30.50 40
96 10.55 30.45 50.50 10.50 30.50 50.50 60
126 4.00a 13.50a 25.00 4.00a 13.50a 25.00 30
14 2 25.65a 25.30a 40.55a 20.25a 27.90a 43.35 60
9 17.73a 24.13a 49.65 17.60a 24.17a 49.72 60
23 12.10 34.72a 44.67a 12.35 34.67a 44.4 7a 60
51 1I.35 30.88 49.28 1I.40 31.05 49.05 60
90 11.90 29.10 50.50 12.40 28.60 50.50 60
120 lUO 29.90 46.50 11.32 29.67 46.50 52
41 10 25.60a 33.72a 32.17a 24.98a 34.28a 32.25a 60
24 25)Oa 27.88a 38.53a 25.55a 27.83a 38.13a 60
63 19.73a 22.17a 49.60 18.lOa 24.20a 49.20 60
93 18.17a 26.85a 46.47 18.70a 26.77a 46.03 60
128 1I.43 29.83 50.25 11.55 29.70 50.25 60

noted for 5-7 day chub larvae transferred from
20 C to 14 C.
Eleven- to 13-day G. CYPha larvae transferred
from 20 C to 10 C also entered cold coma but
regained normal behavior after 15 min. No oth-
er treatment groups (20 C to 12 C or 20 C to
14 C) at this age exhibited obvious adverse be-
havioral effects. No G. CYPha mortality occurred
under any treatment over the 4-h observation
periods.
For the catostomids, only 7-9-day X. texanus

and 7-8-day C. latiPinnis larvae subjected to tem-
perature shock from 20 C to 10 C appeared to
enter cold coma. This condition lasted for 30-
60 sec and 5-10 sec for X. texanus and C. lati-
pinnis, respectively. Thereafter, larvae of both
species periodically "rested" on the aquarium
bottom for 5-10 sec at intervals that increased
over time. This behavior was also apparent at
higher temperatures, including controls, for
both species, but resting times were on the or-
der of 1-3 see. No definitive cold coma behavior

TABLE 2. MULTIPLE COMPARISONS OF LENGTH AND WEIGHT MEAN RANKS (POOLED REPLICATES) ACROSS THREE
TEMPERATURES OF THREE AGES (7, 14, AND 41 DAYS POSTHATCH AT INITIATION OF EXPERIMENT) OF EARLy LIFE
STAGE Catostomus latipinnis. Day is days past initiation of experiment. Superscript denotes comparisons that
were not significant (0. > 0.05) when adjusted for multiple comparisons.
Length Mean Ranks Weight Mean Ranks
Age Day 10 C 14 C 20 C 10 C I4C 20 C N
7 7 1I.48 29.67 50.35 lUO 29.95 50.45 60
14 10.50 30.50 50.50 10.50 30.50 50.50 60
28 10.57 32.35 48.58 10.50 32.55 48.45 60
59 10.50 31.00 50.00 10.50 30.60 50.40 60 "-'
91 10.50 31.83 49.17 10.75 31.55 49.20 60
14 7 13.48 27.85 50.17 12.38 31.58 47.55 60
16 14.57a 27.73a 49.20 15.60a 28.05a 47.85 60
28 15.43 28.65 47.42 16.30a 25.77a 49.42 60
63 11.75 32.33 47.42 11.60 32.25 47.65 60
92 10.80 30.90 49.80 11.02 30.83 49.65 60
41 35 14.45a 19.15a 12.90a 14.60a 19.20a 12.70a 30
64 8.20a 14.30a 24.00 8.50a 14.20ab 23.80b 30