8190

• UCREFRP Catalog Number: 8190
• Author: Papoulias, D. and W. L. Minckley
• Title: Effects of Food Availability on Survival and Growth of Larval Razorback Suckers in Ponds
• USFW Year: 1992
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

FEEDING BY LARVAL RAZORBACK SUCKERS 351
TABLE 4.-Continued.

Common and
species name Con-
tainer
volume
(L)

Time
(d) Stock
density
(num-
ber/L)

ood Food
density
(num-
ber/L)
Food items
per fish
(number/d)
Sur-
vival
N

uthority
6,000 1,500 37
3,000 750 20
Striped bass 28 Zooplanktone -650 63 Geiger et al.
Moron saxatilis -250 46 (1985)
Striped bass 8 24 0.32 Anemia 5,000 15,625 90 Eldridge et al.
Moronesaxatilis naupliid 1,000 3,125 85 (1981)
500 1,562 75
100 312 55
10 31 30
Razorback sucker 3.9 50 2.6 Artemia 1,000 1,154 88 Papoulias and
Xyraucken texanus naupliit 500 577 90 Minckley
100 115 80 (1990)
50 58 82
10 12 28
5 6 12
a Food adjusted once per day.
b Average food available per day.
c New food added twice per day.
d New food added once per day.
e Ten-day-old larvae stocked into 0.04-hectare ponds at 371,000 fry/hectare
rNew food added three times per day,
zorback sucker larvae in Lake Mohave ate cla-
docerans most abundantly, along with rotifers and
copepods (Marsh and Langhorst 1988).
Direct applications of our pond data to situa-
tions in nature are speculative; however, reser-
voirs on the lower Colorado River generally are
low in zooplankton (Table 5) and oligo- or me-
sotrophic in productivity (Paulson et al. 1980).
Lake Mohave has variable but higher primary
productivity than most reservoirs due to inflows
of nutrient-rich hypolimnetic water from Lake
Mead (Priscu 1978; Priscu et al. 1982). Spatially,
annual mean zooplankton densities in Lake Mo-
have tend to be lowest at stations near inflow of
hypolimnetic water from Lake Mead and highest
in the body of the lake (Cottonwood Basin) to near
Davis Dam (Table 5; Paulson et al. 1980); razor-
back sucker larvae are concentrated in Cotton-
TABLE 5.-Historic zooplankton concentrations for three Colorado River reservoirs

Year im-
Lake pounded

tudy year Zooplankton
(number/L)
Yearly Spring
average average

ocation

ethod

uthority
Mead 1935 1975-1976 41.0 Lakewide 0-45 m depth Burke (1977)
1977-1978 -33.8 At dam 0-40 m depth Paulson et al. (1980)
1978-1979 37.4 Lakewide 20 m horizontal, McCall (1980)
0-20 m vertical
1981-1982 25.2 35.4 Lakewide Wilde (1984)
Havasu 1938 1982-1983 82.7 49.1 Lakewide Baker and Paulson
(1983b)
Mohave 1954 1977-1978 29.0 Lakewide 0-40 m depth Paulson et al. (1980)
1977-1978 45.5 Cottonwood Cove 0-40 m depth Paulson et al. (1980)
1977-1978 1.8 Below Hoover Dam To bottom Paulson et al. (1980)
1982 -35.0 26.3 Cottonwood Cove 0-40 m depth Paulson et al. (1980)
1985 1.5 Cottonwood Cove Surface Marsh and
Langhorst (1988)
1985 0.4 Cutoff bay Surface Marsh and
Langhorst (1988)