8145

• UCREFRP Catalog Number: 8145
• Author: Bozek, M. A., L. J. Paulson and G. R. Wilde.
• Title: Effects of Ambient Lake Mohave Temperatures on Development, Oxygen Consumption, and Hatching Success of the Razorback Sucker.
• USFW Year: 1989.
• USFW - Doc Type: \
• Copyright Material: YES

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OeveIopmenl.ll stages

Fig. I. Oxygen COftSUR\('lioR of eg. enlbryo lIftd larva sta&l-~ of
r.azorbaCk sucker. x"..udwn I~X(lllUS. at three t.k.-veIopmL'1Ital
temperatures (10. IS. and 20" C). Devetopmemal Slagcs corre-
spond to Mindi.\ey It. GUSlafson (1982) and are: a - moruW
bastula. b- pre.taiIbud. (- pre-hatch. d - post-hatch. c - swim-
up. and f _ yolk depIctioo. ()xyaen consumption valueS are the
means and c:orrnponding 95% confIdenCe interVals.

high as 20 C occurring in February ll.)l'\~. B;lsed
upon developmental rates at 100 C.larvae collected
in January 1982 probably were the result of spawn-
ing in early December or late November 1981. No-
vember through January arc the coldest seasonal
watcr temperature months in Lake Mohavc.
The highest density of larvae was found in the Six
Mile Coves area in February 1983 when 10 larvae
min-I were collected at a depth of 1.1 m. Larvae
were less abundant on that date in deeper water
over the spawning area. Water temperatures dur-
ing collecting were 12.O"C during the day and
10S'C at night.
Although larvae were abundant in the Six Milc
Coves area in February. no larvae were collected
from this site in March. Severe winds and heavy
wave action preceding the coUection dates disrupt-
ed and likely decimated redds in the spawnint. area.
Spawning in this area was abandoned for the re-
mainder of the year following the storm but contin.
ued in other areas of the reservoir that presumably
were more protected a~ evidenced by larvae col-
lected from Tequila Covc.
Total lengths of wild-caught larvae on different
sampling dates ranged from 10.4::t 0.5 to J 1.1 ::t
O.5mm (mean::t lsd). The largest was 12.6mm
and in the early mesotarval stages of development.
No larvae collected were past this stages of clevel-

T.bI~ 2. Hatching success of razorback sudtm as a function of water temperature. P~rc:..'1I' viable ....t"... of normal ,,'1I1hryus :m:
expressed as the mean:!: one 5tlIndard deviation.
Experiment Spawning Incubation Number of No. of ova per "" viahIe ....tch % viabk h:udl
temperature temperature replicates replicate (mean) (range)
A 11.0 10 2 2.~ 57 .3 j: V. (5:!.2~.3)
8 12.8 10 1 626 21.9 na
12.8 15 1 SNO 32.2 na
12.8 20 I 601 33.6 na
C 11.0 8 4 SO 0.0 na
11.0 12 4 SO 36.0:t 10.M (2lI.u-44.0)
11.0 15 4 SO 39.5 :t 4.9 (3-U1-46.0)
11.0 20 4 50 3H.O j: 4.M (34.0-4'-11)
D 13.0 II 4 70 0.0 na
13.0 10 4 70 36.3 j: 7.3 (27.0-44.0)
13.0 15 4 70 64JI:t 5.U (59.0-71.0)
13.0 20 4 70 64.5 :t 3.R (6W-70.0)
na = not applicable.

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