9489

• UCREFRP Catalog Number: 9489
• Author: Mueller, G.
• Title: The Role of Stocking in the Reestablishment and Augmentation of Native Fish in the Lower Colorado river Mainstream ‎(1998-2002)‎.
• USFW Year: 1998-2
• USFW - Doc Type: 03-288,
• Copyright Material: YES

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HAZARD OF INORGANICS TO ENDANGERED FISH

Hatchery, Dexter, New Mexico, courtesy of the U.S.
Fish and Wildlife Service. The eggs were packed in
commercial (polystyrene) egg-shipping containers and
shipped by air to the Yankton Field Research Station,
Yankton, South Dakota, for testing. Upon arrival, eggs
were acclimated to 23 :!:: 20C over a 2-hr period and then
placed in a Heath incubator. Fry were held in 70-liter
aquaria in flowing water maintained at 23 :!:: 20C. Fish
were fed a commercial diet (Biodiet, Bioproducts Inc),
supplemented for the first 30 days with live nauplii of
brine shrimp (Artemia sp.). The water quality for egg and
larval culture was pH 7.7-7.9, hardness 233-330 mg/liter,
and alkalinity 174-226 mglliter.
All tests were conducted in a reconstituted water qual-
ity designed to simulate site-specific conditions for major
cations and anions, without trace elements, in the Green
River near Jensen (ReMillard et aI., 1989) (Table 1). Re-
constituted water was prepared by adding calcium sul-
fate, magnesium sulfate, calcium chloride, and sodium
bicarbonate to deionized water in a 5700-liter polyethyl-
ene tank equipped with a recirculating pump to mix and
aerate the water (Hamilton et al., 1989). Water quality
characteristics were measured for each tank of dilution
water as follows: calcium, sulfate, total hardness, and
total alkalinity were determined according to methods of
the U.S. Environmental Protection Agency (USEPA,
1979); magnesium concentrations were calculated from
calcium and hardness values; chloride was measured
with a Buchler chloridometer; specific conductance (cor-
rected to 250C) was measured with a YSI Model 31 con-
ductivity bridge with a cell constant of K = 1.0; and pH
was determined with an Orion Model 901 Ionalyzer using
a Ross combination electrode.
The inorganic compounds used in acute toxicity tests

TABLE 1
Water Quality Characteristics of Reconstituted Middle Green
River Basin Water (N = 18 Tanks of Blended Test Water)

Experimental Test water
Parameter design Mean :!: SD Range
Conductivity
(~mhos/cm at 25OC) 610 :!: 32 550-672
pH 7.8 :!: 0.3 7.3-8.2
Hardness as CaC03 197 196 :!: 5 /82-201
Calcium 46 46:!: t 44-48
Magnesium 20 20 :!: I 17-21
Sodium 49 49a
Alkalinity
as CaC03 107 107:!: 2 /03-111
Chloride 23 20 :!: 2 16-23
Sulfate 159 164 :!: 7 152-t74

Note. Units are mglliter unless noted otherwise.
a Nominal concentration.

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were boric acid, lithium chloride, sodium selenate, so-
dium selenite, sodium vanadate, uranyl nitrate, and zinc
chloride. Test solutions were prepared by either pipetting
appropriate aliquants of stock solution or adding the com-
pound directly to the test vessels. Stock solutions were
formulated in deionized water on the day of use. Nominal
concentrations given here were expressed as the total
inorganic toxicant added, as determined from the certif-
icate of analysis for each compound.
Static acute toxicity test procedures used in tbi's study
closely followed those outlined by the American Society
for Testing and Materials (ASTM, 1989). Each test con-
sisted of exposing groups of 10 fish to a geometric series
of 6-8 nominal toxicant concentrations and a control
treatment for 96 hr. Tests with fry were conducted in
3.8-liter glass jars filled with 3 liters of test solution and
those with juveniles in 19.6-liter glass jars filled with 15
liters of test solution. For larger juveniles (1.2 g),dupli-
cate sets of jars were used, and only five fish Were placed
in each jar to maintain loading densities of 0.8 g/liter or
less. Temperature was maintained at 25 :!:: laC by im-
mersing the jars in temperature-controlled water baths.
Because of their rapid rate of development, fry were ac-
climated to the dilution water for only 24 hr before test-
ing. Juveniles were acclimated simultaneously to the di-
lution water and test temperature over a 2-day period and
were held in the dilution water for 2 days prior to testing.
The fish were not fed during acclimation or testing.
At the start of each test, fish were randomly-distributed
to the test vessels within 30 min after the addition of the
toxicant. To minimize handling stress, fry were first
transferred to 50-ml beakers, containing a small volume
of dilution water, using a glass pipet fitted with a suction
bulb. After 10 fish were placed in a beaker, most of the
water was decanted and the fish were gently poured into
the jars. Juveniles were carefully netted from the holding
tank and distributed in groups of two to each jar. Mor-
tality was recorded, and:-all dead fish were removed at
24-hr intervals. Fry without perceivable movement ofthe
pectoral fins were pipetted from the jar and examined
under 30x magnification for the absence of a heartbeat,
which was the criterion for death. Total length and weight
of the control fish were measured at the end of the tests.
There was no mortality in the control treatments from the
tests.
Dissolved oxygen and pH were measured at the begin-
ning and end of the tests in the control, low, medium, and
high treatments with live fish present. Dissolved oxygen
was measured with a YSI Model 57 oxygen meter and pH
with an Orion Model 901 Ionalyzer with a Ross combi-
nation electrode. Dissolved oxygen concentrations were
maintained at or greater than 40% saturation in most
tests; however, fish in control and low treatment tests