Effects of seepage on water quality and productivity of inorganically fertilized tropical ponds

D.R. Teichert-Coddington and R.P. Phelps, Department of Fisheries and Allied Aquacultures, Alabama Agricultural Experiment Station, Auburn University, Alabama 36849, USA

4 December 1989, CRSP Research Report 89-21

Abstract Twelve earthen ponds (870 m² by 0.9 m) located on permeable, acidic soils in Gualaca, Panama, were limed and stocked with Oreochromis niloticus at a rate of 1/m2. Ponds were fertilized every two weeks with triple superphosphate (42% P₂O₅) at a rate of 4 kg/ha P₂O₅). Seasonal means of primary production, chlorophyll a, filterable orthophosphates, total phosphorus, total alkalinity, total hardness, and fish production were correlated with the mean seepage for each pond. The same experiment was accomplished during both the dry and wet seasons of 1985.

Mean seepage for all ponds ranged from 19 to 58 mm/day. Of the chemical variables, only total alkalinity and total hardness consistently decreased with increasing seepage rates. Primary production and chlorophyll a were not correlated with seepage. Fish production was unrelated to seepage during the dry season when total alkalinities were high, ranging from 37 to 60 mg/l CaCO₃, but significantly decreased with high seepage during the wet season when total alkalinity became lower than 10 mg/l CaCO₃. The study indicates that ponds located on acidic soils with high seepage rates will require significantly greater additions of lime to maintain alkalinity and hardness levels suitable for fish production.

This paper was published in Journal Aquaculture in the Tropics, 4:85-92 (1989)

Integrated lake farming for fish and environmental management in large shallow Chinese lakes: a review

W.Y.B. Chang, Center for Great Lakes and Aquatic Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA

18 January 1990, CRSP Research Report 90-22

Abstract Large shallow lakes in the Pacific Drainage Basin of China are unique aquatic natural resources intensively exploited in recent years for integrated lake farming. This paper presents a general description and major components of this culture method and discusses potential concerns and effects of increased fishery production on aquactic environments.

This paper has been accepted for publication in Aquaculture and Fisheries Management 1989, 20:441-452.

A multivariate model of tilapia growth, applied to seawater tilapia culture in Kuwait

K.D. Hopkins and M.L. Hopkins, College of Agriculture, University of Hawaii at Hilo, Hilo, Hawaii, 96720, USA

D. Pauley, International Center for Living Aquatic Resources Management, MC P.O. Box 1501, Makati, Metro Manila, Philippines

30 January 1990, CRSP Research Report 90-23

Abstract Traditional analyses of aquaculture growth experiments usually consider only the yield at the end of the experiments and ignore the growth data collected during intermediate samplings. A multivariate model based on an expansion of the "Gulland and Holt Plot" used in fisheries biology provides a methodology to extract growth information from the data from intermediate samplings. This model is applied to data from three tilapia yield experiments conducted in seawater in Kuwait. The effects of temperature, sex ratio, and fish length on growth rate are quantified.

This paper was published in The Second International Symposium on Tilapia in Aquaculture .p.29-39, 1988. R.S.V. Pullin, T. Bhukaswan, L. Tonguthai,and J.L. MacLean (eds.) ICLARM Conference Proceedings 15, Department of Fisheries, Bangkok, Thailand, and International Center for Living Aquatic Resources Management, Manilla, Phillippines.

Comparative production of Colossoma macropomum and Tilapia nilotica in Panama

Mendardo Peralta, Estacion Experimental De Dulce-Acuicola, Gualaca, Chiriqui, Panama

David Teichert-Coddington, Department of Fisheries and Allied Aquacultures and Alabama Agricultural Experiment Station, Auburn University, Alabama, 36849, USA

31 January 1990, CRSP Research Report 90-25

Abstract The production of Colossoma macropomum (tambaqui), a relatively little studied fish from the Amazon and Orinoco basins, was compared with that of Tilapia nilotica, a fish well known for its good production characteristics. The experimental design was randomized and arranged in 2 x 2 factorial with each species being tested at 2,500 and 10,000 fish/ha. Treatments were replicated three times. Fingerlings (22-31 g) were stocked into 870 m2 earthen ponds, fed a commercial diet (25% protein), and harvested after 129 days. Mean yield (kg/ha) for tilapia at high and low density was 3,361 and 917, respectively, and for Colossoma was 3,682 and 977, respectively. The yield difference between species was not significant (P < 0.01). Although yield was not different for the species, tambaqui weight gain was significantly greater than that of adult tilapia because of reproduction in the tilapia ponds. Mean tilapia and tambaqui weight gains (g) for low density were 379 and 471, respectivley, and 321 and 395, respectively, for high density. Increasing the stocking density fourfold resulted in an almost fourfold increase in net yield for both species, although individual weight gains were not significantly affected. There was no interaction between species and density for the production characteristics studied.

This study concluded that under culture conditions that included a short growth period, high quality rations, and stocking rates up to 10,000/ha, production of tambaqui was equal to, or better than that of tilapia. Also, stocking rates lower than 10,000/ha would result in lower yields of both species while not producing a significantly larger fish.

This paper was published in Journal of the World Aquaculture Society, 20: 236-239, December, 1989.