Submitted to: Southern Division American Fisheries Society Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 11/11/2005
Publication Date: 2/12/2006
Citation: Ludwig, G.M., Lochmann, S. 2006. Growth and survival of sunshine bass larvae stocked in tanks at different densities [abstract]. Southern Division American Fisheries Society Annual Meeting. Paper No. 100672. Interpretive Summary: Sunshine bass fingerling culture in tanks allows easier control of temperature, oxygenation, feeding enumeration and monitoring of health and growth. To be cost effective, conditions of tank culture must be optimized. This experiment attempted to determine how many fish per volume of water should be stocked in order to maximize growth, survival and profit. Sunshine bass, 5 days after hatching, were stocked into 100L of water at stocking rates of 30 to 130 fry per liter. The fry were first fed rotifers, then brine shrimp nauplii and then manufactured feed before being harvested when the fish were 26 days old. Samples of fish from each tank were photographed while they were alive to determine length. The fish were also weighed. Survival ranged from 32 to 79% and averaged 60% and increased slightly with stocking rate. The total weight of fish harvested ranged from 14 to 22 mm and was not affected by stocking rate. Individual fish weight and length decreased as more fish were stocked. Maximum yield was achieved when fish were stocked at 86 per L. The optimum stocking rate for realizing maximum gross profit was 110 per liter. The amount of fish harvested was more than that usually harvested from a half acre of pond while only 3% of the water used for pond culture of the same amount of fish.
Technical Abstract: In order to be cost effective, conditions for tank culture must be optimized. This experiment attempted to determine the relationship among stocking density of sunshine bass larvae in tanks and growth and survival. Sunshine bass larvae, 4 days post hatch (dph), were stocked into blue, polyethylene tanks with 100 L of 8 ppt brackish water. Light intensity at the water surface was about 900 lumens. Larvae at 9 densities, ranging from 29 to 118 larvae/L were stocked into 10 tanks. Rotifers, cultured with Nannochloropsis and Culture Selco® 3000 were fed 4 times per day at 15 rotifers/ml until 12 dph. From 8-12 dph Artemia nauplii were fed 4 nauplii/ml once per day; every four days an additional feeding/day was added until at 22 dph 20 nauplii/ml/day were fed. Six grams of a 55% protein salmon starter meal was fed throughout the day with a belt feeder from 19 dph until 22 dph when the meal was increased to 8 grams/day. Fish were harvested at 26 dph and enumerated gravimetrically. About 30 fish from each tank were photographed and total length and other morphometrics determined. Optimum stocking density for maximum biomass production occurred between 80 and 90 larvae per liter. . The optimum stocking rate for realizing maximum gross profit was 110 per liter. The amount of fish harvested was more than that usually harvested from a half acre of pond while only 3% of the water used for pond culture of the same amount of fish.