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

and Miller (1957), Tatum et al. (1966), Bayless (1972), Davies (1973), Shell
(1974), and Lal et al. (1977). Rees (1977) found no overall difference in
hatching success or fry survival among groups of eggs hatched at salinities
of 0, 1,000, and 3,000 mg/1 at 18.9° C (66.1° F). Morgan et al. (1981) noted
that the effect of salinity on the development of striped bass is complex and
that, although salinity does not directly influence percent hatch of eggs,
there is a significant interactive effect of salinity and temperature on
percent hatch, as well as on percent survival of larvae. Larvae held in water
with salinity levels of 3,000 to 5,000 mg/1 and then stocked in earthen ponds
in Alabama, with the salinity level of the water between 3,000 to 8,000 mg/l,
survived well (Crance 1985).
Tagatz (1961) reported that juveniles survived abrupt transfers between
salt and fresh water at temperature differences from 12.8 to 21.1° C (55 to
70° F), but were not tolerant to transfers from fresh water to salt water at
7.2° C (45° F). Adults were tolerant of abrupt changes between salt and fresh
water at differences in temperature from 7.2 to 26.7° C (45 to 80° F).
~H. The tolerance range of larvae and young juvenile striped bass appears
to be about pH 6 to 10 (Bonn et al. 1976; Regan et al. 1968; Shannon 1968;
Bailey 1975); the optimum range is about pH 7.5 to 8.5 (Bogdanov et al. 1967;
Davies 1973; Bonn et al. 1976). Rapid changes in pH can be lethal to young
juveniles (Tatum et al. 1966). Regan et al. (1968) reported that mass
mortality of larvae occurred within 4 hours after being subjected to a change
in pH from 7.5 to 9.9. Doroshev (1970) reported 100% mortality of larvae
subjected to a change of 0.8 to 1.0 pH units. Combs (1979) concluded that
there was no relation between pH and striped bass production in the Arkansas
River, Oklahoma, where the mean daily pH ranged from 7.3 to 8.5. The U.S
Environmental Protection Agency (1976) recommended a pH range of 6.5 to 9.0
for freshwater aquatic life but cautions that the toxicity of some compounds,
such as cyanide, increases as the pH is lowered and that the toxicity of
ammonia may increase 10 times when the pH increases from 7.0 to 8.0.
Contaminant load. Quality criteria for freshwater aquatic life developed
by the U.S. Environmental Protection Agency (1976), a review of EPA's criteria
(Thurston et al. 1979), and quality criteria for water adopted by States are
useful references for determining contaminant levels acceptable for striped
bass habitats. Stevens et al. (1985) attributed toxic substances as one of
the most likely causes of decline of striped bass in the Sacramento-San Joaquin
Estuary, California.
Physical barriers. Dams or other physical barriers that prevent fish
passage may e]iminate access to spawning habitat. Fishways have not proven
satisfactory for striped bass (Talbot 1966).
Stream width. Extremely narrow streams can prevent adult striped bass
from moving to spawning sites. However, width was not considered to be an
important variable that determines riverine habitat suitability (Crance 1985).
Stream length. If spawning occurs in riverine habitat, a minimum distance
from the spawning site to lacustrine habitat is required (see section on
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