ARCHIVAL WEBSITE
You are viewing the archived website of Pond Dynamics / Aquaculture CRSP. When using this website, please understand that links may be broken and content may be out of date. You can view more information on the continuation of PD/A CRSP research archived at AquaFish Innovation Lab.
Southeast Asia


E. Southeast Asia

Timing of Supplemental Feeding for Tilapia Production

Work Plan 6, Thailand Study 7

James S. Diana
School of Natural Resources and Environment
University of Michigan
Ann Arbor, Michigan, USA

C. Kwei Lin and Yang Yi
Agricultural and Food Engineering Program
Asian Institute of Technology
Bangkok, Thailand

Abstract

The effect of timing of feed application on fish growth and yield was evaluated for Nile tilapia. Fish were stocked into 15 ponds on 15 January 1993 at 3 fish m-2, and the ponds were grouped into 5 treatments. Each treatment differed by the average size that fish achieved before supplemental feeding began, with treatments at 50 g, 100 g, 150 g, 200 g, and 250 g. Fish were fed at satiation rates until they reached 500 g in average weight. All treatments showed a similar growth rate prior to feeding and a similar rate after feeding, regardless of when feeding was initiated. First supplemental feeding varied from 38-234 days after stocking, and harvest occurred after 236-328 total days of culture or 94-198 days of feeding. Yield varied from 10,420 to 28,178 kg ha-1 yr-1. Fish growth (g d-1) was correlated to days of culture, feed input, and chlorophyll a content (R2 = 0.889, p < 0.001).

Stocking Density and Supplemental Feeding in Tropical Fish Ponds

Work Plan 6, Thailand Study 6

James S. Diana
School of Natural Resources and Environment
University of Michigan
Ann Arbor, Michigan, USA

C. Kwei Lin and Yang Yi
Agricultural and Food Engineering Program
Asian Institute of Technology
Bangkok, Thailand

Abstract

The relationship between density, complete feeding, and carrying capacity was examined for Nile tilapia. Nine ponds were subdivided into three treatments and stocked with fish on 11 November 1993. Treatments included fish stocked at 3, 4.5, or 6 per m2. Fish were fed to satiation daily. Water chemistry and other parameters were monitored biweekly. Ponds were harvested on 15 July 1994 (242 days). Unfortunately, some ponds had few fish remaining at harvest, probably as a result of poaching. Growth rates were similar among treatments, and ponds with high biomass had no indication of limited water quality. Ponds also showed no evidence of having reached carrying capacity. Due to poaching problems this experiment will be redone with a higher stocking density.

Supplemental Feeding of Tilapia in Fertilized Ponds

James S. Diana
School of Natural Resources and Environment
University of Michigan
Ann Arbor, Michigan, USA

C. Kwei Lin
Agricultural and Food Engineering Program
Asian Institute of Technology
Bangkok, Thailand

Kitjar Jaiyen
Department of Fisheries
Ministry of Agriculture and Cooperatives
Kasetsart University Campus
Bangken, Bangkok, Thailand

Abstract

(Printed as submitted)

The addition of feed to fertilized fish ponds was evaluated by adding feed alone, feed plus fertilizer, or fertilizer alone to nine ponds stocked with Nile tilapia Oreochromis niloticus. Two experiments were conducted. The first had 500 fish per 250 m2 pond in 3-treatments: ad-libitum feeding; fertilizer only; or fertilizer and ad-libitum feeding. The second experiment had 5 treatments with 750 fish per pond: ad-libitum feed only; fertilizer only; or 0.25, 0.50, and 0.75 satiation ration plus fertilizer. Ponds in Thailand were maintained for 155-162 d, during which chemical and physical properties were monitored. In experiment 1 tilapia growth was highest in feed only ponds, and lowest in fertilizer only ponds. Net yield did not differ significantly among treatments, due to variation in survival. In experiment 2, tilapia growth was lowest in fertilizer only ponds, intermediate in 0.25 ration ponds, and highest in 0.50, 0.75, and ad-libitum ponds. The latter treatments were not significantly different. Multiple regressions for each experiment indicated only 47-87% of the variance in growth was explained by feed and fertilizer input, while 52-89% of the variance in yield was explained by those factors. For both experiments combined, 90.3% of the variance in growth was explained by feed input, fertilizer input, alkalinity, and total inorganic nitrogen concentration. For yield, R2 was 0.888 and the regression included feed input, pH, and number of low dissolved oxygen events. Experiment 1 appeared to approach carrying capacity near the end, while no reduction in growth occurred in experiment 2 at higher fish density and biomass. Reductions in growth in experiment 1 were not correlated with declining water quality late in the grow out. Combinations of feed and fertilizer were most efficient in growing tilapia to large size (500 g) compared to complete feeding or fertilizing alone.

Appeared in Journal of the World Aquaculture Society 25(4).