Kevin D. Hopkins, College of Agriculture, University of Hawaii at Hilo, 200 W Kawili St Hilo, HI 96720
James E. Lannan, PO Box 594, Blodgett, OR 97326
James R. Bowman, Department of Fisheries and Wildlife, OSU, 104 Nash Hall, Corvallis, OR, 97331-3803
September 1987, CRSP Research Report 87-1
Abstract This paper describes a data base management system used in the analysis and synthesis of data from a global experiment investigating dynamics of tropical farm ponds. Data synthesis is directed toward developing comprehensive farm pond management models. The experimental plan includes standardized data collection on physical, chemical and biological variables on 12 or more ponds at each of seven locations in Africa, Central America, and Southeast Asia.
Field data from each location are compiled on microcomputers at the project sites. Project staff at each site perform routine statistical analyses and presentations of these data sets using statistical and graphics software packages of their choice. Field data are forwarded to a central office for filing on a mainframe computer. More sophisticated data analysis and syntheses (modeling) are done on mainframe computers.
The standardized experimental design and centralized data base management system facilitates analyses of observations within ponds, between ponds within locations, and between locations. This design allows identification and analysis of both general and site-specific considerations over a broad range of environmental conditions. We propose that aquaculture scientists standardize data collection and management to permit direct comparisons of observations among and between research projects. The resulting comprehensive data base will improve understanding of the dynamic processes that regulate productivity in tropical farm ponds.
This is the first paper published in CRSP Research Reports. It was submitted in November 1986, and approved for publication in September 1987.
Idiopathic muscle necrosis in the freshwater prawn, Macrobrachium rosenbergit de Man, cultured in Thailand
G. Nash, Institute of Aquaculture, University of Stirling, Stirling, Scotland
S. Chinabut, National Inland Fisheries Institute, Kasetsart University Campus, Bangkhen, Bangkok, Thailand
C. Limsuwan, Faculty of Fisheries, Kasetsart University, Bangkhen, Bangkok, Thailand
30 November 1987, CRSP Research Report 87-2
Abstract A mass mortality of up to 60% per tank occurred in 28-day-old Macrobrachium reosenbergii postlarvae cultured under intensive conditions in a hatchery in Thailand. Grossly affected prawns displayed a diffuse 'milky' white body opacity; histologically and ultrastructurally, segmental myofibre (myofibrillar and sarcoplasmic) necrosis unassociated with any infectious agents was observed and diagnosed as idiopathic muscle necrosis. Avoidance of overstocking and increased dissolved oxygen in tank water have proved effective in preventing subsequent recurrence of the condition.
This paper was published in Journal of Fish Diseases 1987, 10: 109-120.
P. Tavarutmaneegul, Pathum Thani Fisheries Station, Nong-Sua, Pathum Thani, Department of Fisheries, Thailand
C. Kwei Lin, Great Lakes Research Division, The University of Michigan, Ann Arbor, Michigan 48109, USA
30 November 1987, CRSP Research Report 87-3
Abstract Large-scale production of sand goby fry was conducted at the Nong-Sua Hatchery Station, Thailand, for one year. Approximately 1,000 egg nests containing 25 million eggs were collected from January through October under semi-natural breeding conditions. The hatching rate of fertilized eggs reached 80%. Fry were reared in two stages. In stage 1, the newly-developed fry, with average total body length of 4 mm and mouth clutch opening of about 0.1 mm, were first fed with a combination of chicken-egg slurry and live rotifers. The survival rate at this stage ranged from 7 to 55%, with an average of 20% among batches of egg nests collected during the year. Stage 2 involved raising older fry that were fed with live Moina sp., chironomid larvae, and ground trash fish from days 30 to 60, during which the survival rate ranged from 60 to 90% and length increased from 2.4 to 3.8 cm. Growth rate was inversely related to stocking density at this stage. A total of 147,300 juvenile fish was produced in the one-year effort.
This paper was accepted for publication in Aquaculture1988, 69:299-305.
C. Kwei Lin , Great Lakes and Marine Water Center, University of Michigan, Ann Arbor, Michigan USA
27 January 1988, CRSP Research Report 88-4
Abstract An experiment was conducted to examine the chemical characteristics of and the effects of fertilization on water quality and biological productivity in fishponds built in the acid sulfate soil region of Thailand. The acid soil acidified the overlying pond water rapidly to pH less than 4, but its acidification effect was reduced remarkably by repeated changing of the pond water with alkaline source water. Further improvement of the pond water was done by liming and enriching the ponds with inorganic and organic fertilizers. The pH in ponds receiving inorganic fertilizers (N16P20K0) fluctuated widely necessitating repeated liming. Production of food organisms (phyto- and zooplankton) was relatively poor. Fish yield (Oreochromis niloticus and Puntius gonionotus stocked at a density of 3 fish/m2) in five months was only 426 kg/ha. In comparison, the pH in ponds fertilized with chicken manure stabilized in the alkaline range and fluctuated little after initial liming. Relatively high plankton production were achieved and fish yield was 1,528 kg/ha. Methods of reclaiming the acid soils for productive fishponds are recommended.
This paper originally appeared in the Proceedings of the First Asian Fisheries Forum J.L. Maclean, L.B. Dizon,and L.V. Hosillos (eds.) Asian Fisheries Society, Manila, Philippines, 1986, pp. 71-74.
Leah May B. Ver, Yvonne N. Chiu, Brackishwater Aquaculture Center, College of Fisheries, University of the Philippines in the Visayas Leganes, Iloilo City, Philippines
8 February 1988, CRSP Research Report 88-5
Abstract In intensive pond fish culture, good water quality is critical for fish growth and survival. Various water management techniques have been developed to maintain adequate levels of dissolved oxygen and to prevent the accumulation of ammonia and carbon dioxide to toxic levels. This study investigated the effect of paddlewheel aerators on the removal of ammonia and carbon dioxide and to ascertain its well-established effect of maintaining optimum dissolved oxygen levels in ponds sustaining a high biomass. A 500-m2 earthen pond was stocked with Oreochromis niloticus averaging 170 g each to attain a total biomass of 3,000 kg/ha. Un-ionized ammonia and carbon dioxide levels were monitored every four hours for both aerated and unaerated conditions in the same pond. Each treatment was monitored over 24-hour cycles. Results indicate as significant effect of aeration on the diel pattern for carbon dioxide but none on ammonia. Carbon dioxide levels accumulated through the night and peaked between 4 and 8 a.m. at which time aeration significantly reduced it. Ammonia concentration was highest at 4 p.m. regardless of treatment.
This paper originally appeared in the Proceedings of the First Asian Fisheries Forum J.L. Maclean, L.B. Dizon,and L.V. Hosillos (eds.) Asian Fisheries Society, Manila, Philippines, 1986, pp. 97-100.
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