Stress in Shad

Shad stress out when caught, handled or being chased or transported. Stress is adrenaline released into the bloodstream. Adrenaline is followed closely by other steroids such as cortisol, which prepare the fish for its reaction. The result is raised blood glucose levels, red blood cell counts, heart and ventilation rates. The digestive processes may cease temporarily.
e.g., escape (Mazeaud and Mazeaud, 1981).

Adrenaline disturbs ion transport at the gill membrane, and both adrenaline and cortisol cause temporary changes in gill permeability which, in fresh water, results in dilution of the blood by excessive gain of water, and vice versa in normal seawater.
(Mazeaud et al., 1977; Folmar and Dickhoff, 1980).

Blood levels of calcium, magnesium, sodium, and other vital electrolytes are pushed out of normal operating ranges for as much as 24 hours after stress such as being caught in a casting net.
(Wedemeyer, 1972).

Trying to restore physiological and metabolic order diverts precious energy, which leaves the shad less capable of fighting pathogens. Cortisol elevation itself suppresses immune system function.
(Barton et al., 1987; Maule et al., 1987).

A general recipe may be found in Spotte, (1970).

Alternately, concentrations of single ions or salts reflecting their occurrence in natural seawater may serve (for sodium chloride, this will be of the order 0.5 to one percent in aqueous solution, to achieve a final salinity of about half that of normal seawater).

The Bulk density of salt approximate (dry, ASTM D 632 gradation) 1.154 (72 lb/ft3)
Since 1 ft 3 = 7.48 gallons, the Bulk density of salt converts to 72 lb / 7.48 gal = 9.6 lb/gal.

And 1 gallon = 16 cups, so salt weighs 9.6 lb/gal X gal/16 cup = 0.6 lb/cup gallon of fresh water is about 8.36 lb

1.0 percent of a gallon of fresh water is 0.0836 lb.

For 50 gal: 50 X 0.139 cups = 6.95 cups
For 30 gal: 30 X 0.139 cups = 4.17

Conversions of salt dosages

1 pound (lb.) = 454 grams (g)
1,000 g = 1 kilogram (kg)

Once the volume is calculated in cubic feet, the gallons are determined using these conversions:

1 ft = 7.48 gallons (gal.)
1 acre-foot (1 surface acre x 1 ft. deep) = 325,850 gal.
1 liter (L)= 0.26 gal.

Calculating tank volume is an important step to effective salt application. Measurements used to determine volume are usually in feet and/or inches.
The most common shapes of tanks are square, rectangular, or round.

Finding Volume of a square or rectangular raceway, tank or pond.
Volume (Vol.) = Length x width x depth

Example 1:

A rectangular tank is 12 feet (ft.) long, 3 ft. wide and 3 ft. deep.
What is its volume?

Vol. = 12 ft. x 3 ft. x 3 ft.
Vol. = 108 cubic ft.

Finding Volume of a round tank
Vol. = 3.14x (radius x radius) x depth

Example 2:

A round tank is 12 ft. in diameter and 4.5 ft. deep.
What is its volume?

(Radius = 0.5 x diameter)
Vol. = 3.14 x (radius x radius) x depth
Vol. = 3.14 X (6 ft. X 6 ft.) X 4.5 ft.
Vol. = 3.14 X 36
Vol. = 508.7 ft

The most commonly used units of measure in aquaculture is the part per million, commonly referred to as ppm.
In percentage calculations, 1% equals 10,000 ppm.

How much salt is needed to make a 2% solution in a round tank ?

salt needed (g) = 0.00378 g/gal. x 3,805.1 gal. x 20,000 = 287,663g or 633.6 lbs. (287,663g = 633.6 lbs.) 454g/lb.

How much salt is needed to make a 0.5% solution in a 100-gal. transport tank?

0.5% = 5,000 ppm
Salt needed (g) = 0.00378 g/gal. x 100 gal. x 5,000 ppm
Salt needed (g) = 1,890 g or 4.2 lbs. (1890g = 4.2 lbs.) 454g/lb