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PD/A CRSP Research Reports 03-186 to 03-190

PD/A CRSP Research Reports 03-186 to 03-190

Evaluation of Nile Tilapia Pond Management Strategies in Egypt

B.W. Green, Department of Fisheries and Allied Aquacultures, Auburn University, AL 36849-5419, USA

Z. El Nagdy and H. Hebicha, Central Laboratory for Aquaculture Research, Agricultural Research Center, Abbassa, Abou Hammad, Sharkia, Egypt

17 January 2003, CRSP Research Report 03-186

Abstract Five pond management strategies for Nile tilapia Oreochromis niloticus L. production were evaluated in 0.1-ha earthen ponds in Egypt during a 145-day production cycle. Pond management strategies developed by the Pond Dynamics/Aquaculture Collaborative Research Support Programme (PD/A CRSP) were compared with a traditional and a modified Egyptian pond management strategy. Young-of-year Nile (mixed-sex or sex-reversed) tilapia were stocked into ponds at 20 000 fish ha-1. Sex-reversed tilapia were stocked into chemical fertilization, organic fertilization plus formulated feed and feed only treatment ponds, whereas mixed-sex tilapia were stocked into organic fertilization plus formulated feed and chemical plus organic fertilization plus formulated feed treatment ponds. Nile tilapia yields ranged from 1274 to 2929 kg ha-1. Nile tilapia yields in organic fertilization plus formulated feed treatments were significantly greater than the yield from chemical fertilization ponds. PD/A CRSP pond management strategies did not produce significantly greater Nile tilapia yields than the traditional Egyptian system, but a larger percentage of harvested tilapia in the organic fertilization plus feed treatments were classified in the first and second class size categories compared with the traditional Egyptian system. Organic fertilization plus formulated feed pond management strategies had the highest net returns, average rate of return on capital and the highest margin between average price and break-even prices to cover variable costs or total costs.

This abstract was based on the original paper, which was published in Aquaculture Research, 33 (2002):1037–1048.


Techniques to Mitigate Clay Turbidity Problems in Fertilized Earthen Fish Ponds

Yang Yi and C. Kwei Lin, Aquaculture and Aquatic Resources Management, Agricultural and Aquatic Systems and Engineering Program, School of Environment, Resources, and Development, Asian Institute of Technology, PO Box 4, Klong Luang, Pathumthani 12120, Thailand

James S. Diana, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109-1115, USA

17 January 2003, CRSP Research Report 03-187

Abstract An experiment was conducted in fifteen earthen ponds at the Asian Institute of Technology (AIT), Thailand, during June to November 1998 to identify the source of clay turbidity mitigation techniques and their effects on fish growth and water quality, and to find a suitable approach for turbidity mitigation during the rainy season. There were five treatments: (A) control; (B) covering upper 50 cm pond dikes with black plastic material to prevent turbidity from run-off (edge-covered); (C) covering pond bottoms with small mesh (1 cm) net to prevent turbidity from fish disturbance (bottom-covered); and (E) covering pond dikes with rice straw (straw-covered). All ponds were fertilized weekly with chicken manure at a rate of 500 kg ha-1 (dry matter basis) supplemented with urea and triple superphosphate (TSP) to provide 28 kg N per ha per week and 7 kg P per ha per week. Sex-reversed all-male Nile tilapia (Oreochromis niloticus) were stocked at two fish per square meter at a size of 19.0±1.0 g. Results showed clearly that clay turbidity was mainly from the run-off of pond dikes but not from fish disturbance of pond bottom during the rainy season and indicated that covering pond dike was effective in mitigating clay turbidity caused by the run-off in fish ponds. No significant differences of fish survival were found among all treatments. The straw- and weed-covered treatments resulted in significantly higher fish growth and yield. In contrast, the edge- and bottom-covered treatments did not increase fish yield, compared with the control. Covering pond dikes with rice straw not only reduces clay turbidity caused by run-off but also enhance Nile tilapia growth probably through microbial biofilm developed on the rice straw. Therefore, covering pond dikes with rice straw is a cost-effective technique for clay turbidity mitigation in fish ponds during the rainy season.

This abstract is excerpted from the original paper, which was published in Aquacultural Engineering, 27 (2003):39–51.


Hybrid catfish (Clarias macrocephalus x C. gariepinus) and Nile tilapia (Oreochromis niloticus) culture in an integrated pen-cum-pond system: growth performance and nutrient budgets.

Yang Yi and C. Kwei Lin, Aquaculture and Aquatic Resources Management, Agricultural and Aquatic Systems and Engineering Program, School of Environment, Resources and Development, Asian Institute of Technology, PO Box 4, Klong Luang, Pathumthani 12120, Thailand

James S. Diana, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109-1115, USA

10 April 2003, CRSP Research Report 03-188

Abstract Two experiments were conducted in 200-m2 earthen ponds at Asian Institute of Technology, Thailand, for 87 days to test the feasibility of an integrated pen-cum-pond system, which utilizes wastes from intensive culture of hybrid catfish (Clarias macrocephalus x C. gariepinus) as nutrients for semi-intensive culture of Nile tilapia (Oreochromis niloticus). This integrated pen-cum-pond system enhances nutrient utilization efficiency, minimizes environmental impacts of pond effluents, and gains extra fish production at low cost. Experiment 1 was designed to compare the integrated pencum- pond systems with natural and artificial water circulation. Six randomly selected 200-m2 ponds were partitioned by 1.0-cm mesh plastic net into two compartments: 1/3 of pond area (67 m2) for hybrid catfish and 2/3 (133 m2) for Nile tilapia. In experiment 2, one additional pond was partitioned by 1.0-cm mesh plastic net into three equal compartments with 67 m2 each. The mesh was not cleaned and thus partitions serve as three replicates for hybrid catfish culture alone (non-integrated system). Experiment 2 was designed to compare growth performance of hybrid catfish and effluent quality from intensive culture of hybrid catfish among the non-integrated system with hybrid catfish alone (non-integrated treatment) and the integrated pen-cum-pond systems (natural and artificial water circulation treatments) in the 67-m2 compartments. The nutrient budgets were also compared among the three culture systems. Sex-reversed all-male Nile tilapia were stocked at 2 fish/m2, and hybrid catfish at 25 fish/m2. Hybrid catfish were fed floating pelleted feed twice daily at rates of 3–10% body weight per day. During the first month, tilapia compartments were fertilized weekly using urea and triple superphosphate (TSP) at rates of 28 kg N and 7 kg P/ha/week. In the artificial water circulation treatment, the water in the catfish compartment was continuously circulated by a submersed pump to the tilapia compartment at a rate of one exchange per week, starting the second month. There were no significant differences in growth performance of hybrid catfish among all treatments (P>0.05). Extrapolated net tilapia yields obtained by using hybrid catfish wastes in this study were comparable to those achieved in organically and inorganically fertilized tilapia ponds. The results indicated that neither natural nor artificial water circulation between catfish and tilapia compartments improved the growth of hybrid catfish. Nile tilapia growth was not significantly different between the natural and artificial water circulation treatments ( P>0.05). However, the artificial water circulation caused mass mortality of Nile tilapia due to heavy loading of wastes. Nutrient budgets showed that total nitrogen (TN) and total phosphorus (TP) levels in pond effluents in the natural and artificial water circulation treatments were significantly lower than those in the non-integrated treatment (P < 0.05). Nile tilapia recovered 3.30% and 2.12% of TN, and 1.29% and 0.84% of TP from feed wastes and fertilizer inputs in natural and artificial water circulation treatments, respectively. Concentrations of TKN, TP and SRP were significantly lower in the natural and artificial water circulation treatments than in the non-integrated treatment (P < 0.05). This study demonstrates that the integrated pen-cum-pond system is feasible, indicates that Nile tilapia can effectively recover nutrients contained in wastewater of intensive catfish culture, and suggests that natural water circulation between catfish and tilapia compartments can reduce nutrient contents in pond effluents and is cost-effective.

This abstract is excerpted from the original paper, which was published in Aquaculture, 217 (2003):395–408.


Potential for Supermarket Outlets for Tilapia in Honduras.

Omar Fúnez, Ivano Neira, and Carole Engle, Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff, Pine Bluff, Arkansas, USA

14 August 2003, CRSP Research Report 03-189

Abstract Honduran tilapia farmers currently face several problems regarding product size and export-quota requirements. One major obstacle is the production of undersized fish not suitable for the export market. Domestic markets would provide stability by offering additional market alternatives, thereby reducing risks associated with having only one target market. The goal of this project was to assess the domestic market as an alternative tilapia outlet. While the overall study includes analyses of supermarket, fish market, and restaurant market outlets, this document will focus on the supermarket segment. A census of the supermarkets listed in telephone books in the major urban areas and eight small towns in Honduras resulted in 54 completed supermarket questionnaires. The analysis provides important insights into supply characteristics, buyer patterns and preferences, and trends in the domestic market. The survey showed that tilapia is a well-known product in Honduran supermarkets. More than 40% of the supermarkets in the country sold tilapia, and 50% of supermarket managers responded that they were either somewhat or very likely to sell tilapia the next year. However, lack of demand, freshness, and seasonal availability were mentioned as primary reasons for not selling the product. Short-term strategies would focus on larger supermarkets catering to international, high-, and middle-income clientele groups. The presence of a specialized seafood section contributes to tilapia sales. Low daily volumes and lack of demand could be addressed through in-store demonstrations, samples, and point-of-purchase information. These results suggest that, provided tilapia farmers combine adequate marketing strategies with availability of high-quality tilapia, it may be possible to further develop the domestic market for tilapia in Honduras.

Order reprints of this paper from the Aquaculture CRSP Information Management Networking Component.


Potential for Supermarket Outlets for Tilapia in Nicaragua.

Carole R. Engle and Ivano Neira, Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff, Pine Bluff, Arkansas, USA

14 August 2003, CRSP Research Report 03-190

Abstract Development of a domestic market for farm-raised tilapia in Nicaragua could provide an economic incentive for development of a farm-raised tilapia industry in Nicaragua. The goal of this project was to assess the domestic market as an alternative market outlet to the export market. While the overall study includes analyses of supermarket, fish market, and restaurant market outlets, this document will focus on the supermarket segment. A census of the supermarkets listed in telephone books in the major urban areas and small towns in the country resulted in 35 completed supermarket questionnaires. Information was collected on both tilapia and other types of fish and seafood sold, prices, most frequently sold fish products, marketing channels, supplier information, attitudes towards tilapia, and store characteristics. Survey results showed that only one-fourth of supermarkets in the country sold tilapia in spite of the substantial fishery for tilapia in Lake Nicaragua. Tilapia were not sold due to off-flavor (tastes like earth), lack of supply, and fears of selling contaminated fish from Lake Nicaragua. Nevertheless, those supermarkets that sold tilapia indicated that their sales in 2000 were higher than they had been in 1999. A high percentage of supermarkets indicated that they were very likely to begin selling tilapia in the coming year. Inconsistent supplies and insufficient quantities were the greatest supply problems. Fresh fillets were preferred but quality and availability needed to be improved. For a domestic market for farm-raised tilapia to develop in Nicaragua, the issue of con-sumer fears of contamination must be addressed. Broad-based consumer education, third-party certification, and labeling programs may be needed to assist consumers to differentiate between farm-raised and wild-caught tilapia. Tilapia farms and processors in Nicaragua will need to guarantee and ensure a consistent supply of good-flavor, high-quality, and safe tilapia products.

Order reprints of this paper from the Aquaculture CRSP Information Management Networking Component.

Previous group of reports: 02-181 to 02-185
Next group of reports: 02-191 to 02-195

To full list of PD/A CRSP Research Reports