7921 ‎(2)‎

• UCREFRP Catalog Number: 7921
• Author: Trembly, T. L. and G. A. Gould.
• Title: Opportunities To Protect Instream Flows In Colorado And Wyoming.
• USFW Year: 1987.
• USFW - Doc Type: Biological Report 87‎(10)‎,
• Copyright Material: NO

Larval. Larvae have little chance for survival if water currents are
insufficient to keep them from settling to the bottom (Barkuloo 1970). Newly
hatched larvae tend to settle to the bottom of an aquarium filled with un-
agitated water despite swimming efforts to remain near the. surface (Pearson
1938; Mansueti 1958). Larvae likely require currents or turbulence for up to
15 hours post-hatch (Meinz and Heubach 1978). Tests conducted by Morgan
et al. (1976) indicated that eggs and larvae have about equal specific gravity.
It is assumed that a minimum current velocity of 30.5 cm/s (1 ft/s), which is
the velocity required to float eggs (Albrecht 1964), is necessary to buoy
larvae until suspension can be maintained by swimming.
Current velocities higher than the minimum required to buoy eggs or
larvae could be detrimental by moving eggs downstream into the slack water of
a reservoir prior to hatching or by carrying larvae into slack water before
they can maintain suspension by swimming. High velocity also may result in
shear levels that damage eggs and/or larvae. Exposure of striped bass eggs to
a shear level of 350 dynes/cm2 killed 36% of the eggs in 1 minute, 69% in
2 minutes, and 88% in 4 minutes; exposure of larvae to 350 dynes/cm2 killed
9.3% in 1 minute, 30.0% in 2 minutes, and 68.1% in 4 minutes (Morgan et al.
1976). Marcy (1971, 1973) and Morgan et al. (1976) presented information
which indicated that a water velocity of about 240 cm/s (7.9 ft/s) created
shears approaching the damaging range for striped bass eggs and larvae.
Lacustrine Habitat Requirements
Water temperature and dissolved oxygen concentration are the principal
variables that determine suitability of lacustrine habitat for striped bass.
Water temperature (U1~Vp, and USA. Temperature preferences of striped
bass likely vary by locale, apparently change with age and an increase in size
(Schaich 1979; Coutant 1980, 1983, 1985), and influence lacustrine habitat
selection by juveniles and adults (Waddle 1979; Coutant and Carroll 1980;
Cheek 1982).
Adult (temperature, VSO. The lower avoidance temperature by adults in
Cherokee Reservoir, Tennessee, was about 18.5° C (65.0° F) (Schaich 1979).
This was near the lower avoidance boundary for adults in coastal waters
(Radovich 1963) but higher than temperatures of 13.9 to 17.2° C (57.0 to
63.0° F) in areas in the San Francisco Bay where many adults spend the summer
(Crance 1985).
Adults in Cherokee Reservoir avoided water above 25° C (77° F) (Waddle
1979; Schaich 1979); adults apparently avoided water temperatures of 24 to
25° C (75.2 to -77.0° F) in Watts Bar Reservoir, Tennessee (Cheek 1982).
Merriman (1941) reported that adults avoided coastal waters above 25 to 27° C
(77 to 80.6° F). Dudley et al. (1977) observed that adults in the Savannah
River, Georgia, avoided temperatures over 26° C (78.8° F). Concentrations of
adults were found in areas of Lake Whitney, Texas, in temperatures ranging
from 27.5 to 29.0° C (81.5 to 84.2° F) when cooler water was available in the
lake (Crance 1985).
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