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%)