15/08/2008 | Use and Application of Salt in Aquaculture
Treatment Methods
The method of salt application depends
on the disease organism, fish
species, weight, and type of aquaculture
unit. Treatment methods
include short-term dips, prolonged
baths, and indefinite treatments.
Dip treatments involve exposing
the fish to very strong solutions for
short periods of time, usually 30
seconds to one minute.
Prolonged baths are useful for
heating fish in small tanks that can
be flushed quickly. Strong solutions
of salt are added to the water. Fish
are held in this salt solution with
aeration from 30 to 60 minutes, or
until they show signs of stress.
Indefinite treatments are used
when-transporting, handling fish, or
when dealing with large volumes of
water, such as ponds. Low concentrations
of salt can be used indefinitely
in ponds.
Calculation of Volumes
Calculating tank and pond volume
is an important step to effective salt
application in aquaculture. Measurements
used to determine
volume are usually in feet and/or
inches. The most common shapes of
culture tanks, ponds, or raceways
are square, rectangular, or round.
Square or rectangular pond and
tank volumes are calculated similarly
except that an average depth is
used for ponds. The method used to
calculate volume of each is given
below.
Volume of a square or rectangular
raceway, tank or pond.
Volume (Vol.) = Length x width x
d e p t h
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. (ft.3)
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 ft.2
X 4.5 ft.
Vol. = 508.7 ft.3
Calculation of dosages
Once the volume is calculated in
cubic feet, the gallons are determined
using these conversions:
1 ft3 = 7.48 gallons (gal.)
1 acre-foot (1 surface acre x 1 ft.
deep) = 325,850 gal.
1 liter (L)= 0.26 gal.
Other useful conversions:
1 pound (lb.)= 454 grams (g)
1,000 g = 1 kilogram (kg)
One of 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. The amount of salt
added to various volumes that results
in 1 ppm concentrations is listed
below.
1 ppm equals:
2.7 lb./acre-foot
0.0283 g/ft.3
0.00378 g/gal.
1.0 milligram (mg)/L
Specific treatments and methods of using salt for
treating various diseases or as a remedial treatment of stress.
External parasites of brood fish
30,000 ppm (3%) as quick dip
(15 seconds) before stocking
External parasites Costia, Epistylis,
Trichodina, and Chilodonella and the
flukes Dactylogyrus and
Gyrodactylus
10,000-30,000 ppm (l-3%)
prolonged treatment (30 minutes
or until fish show signs of .
stress) or 1,000-2000 ppm in
hauling tanks as an indefinite
treatment
Stress during transport and while
handling
Indefinite treatment using 1,000-
10,000 ppm (0.1-1.0%)
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