Cecilia Luz O. Minsalan, Yvonne N. Chiu, Brackishwater Aquaculture Center, University of the Philippines in the Visayas, Leganes, Iloilo City 5920, Philippines
14 December 1988, CRSP Research Report 88-11
Abstract Teaseed cake contains 5.2-7.2% saponin, a glucoside that causes hemolysis in organisms. The higher sensitivity of finfish than crustaceans to the glucoside has made it an effective pesticide in shrimp ponds. To develop management techniques for the use of teaseed cake, the effect of dissolved oxygen (DO) and temperature at levels normally found in shrimp ponds on the potency of the toxicant and its rate of degradation when mixed with water were investigated. The experiments were conducted in 20-1 plastic tanks using two species of finfish, Oreochromis mossambicus and Glossogobius giurus, and two species of crustaceans, Metapenaeus ensis and Penaeus monodon. The experiments were run on a completely randomized design with three replicate tanks for each treatment. In experiment 1, 15 ppm of teaseed cake was needed to eliminate both species of finfishes within sex hours of application. Significant differences in the response of the two species of finfishes were observed. Both species of crustaceans survived concentrations of up to 20 ppm. Results of experiment 2 showed that the decrease of DO levels due to lack of aeration and the increase in water temperature resulting from exposure to sunlight significantly increased the sensitivity of finfish to teaseed cake. Exposure to sunlight for about 12 hours significantly decreased the potency of the glucoside on O. mossambicus in another experiment. The change was small and was not observed with G. giurus. It is recommended that the water level in shrimp ponds be reduced to one third before application, that teaseed cake be applied in shrimp ponds in minimum dosages towards noon when water temperature is higher and that the water depth be restored after about six hours of application.
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. 79-82.
Effects of fertilizers and feeds as nutrient sources on Oreochromis niloticus production in Philippine brackishwater ponds
Romeo D. Fortes, Valeriano L. Corre, Jr., Emelyn Pudadera, Brackishwater Aquaculture Center, University of the Philippines in the Visayas, Leganes, Iloilo City 5920, Philippines
17 December 1988, CRSP Research Report 88-12
Abstract An experiment was conducted to test the effect of chicken manure, 16-20-0, feeds with 20% crude protein (CP) and their combinations on pond productivity and water quality and on the growth and production of Nile tilapia (Oreochromis niloticus) in brackishwater ponds. Results showed low average daily weight increments of Nile tilapia of 0.52 to 1.25 g/day and 0.56 to 1.04 g/day for the first and second runs, respectively. Fish from treatments that received feed (either alone or in combination with chicken manure and/or 16-20-0) were significantly bigger (P<0.01) than fish from treatments without feed. The combination of chicken manure and 16-20-0 did not contribute significantly to the production of tilapia. Higher temperatures were obtained in the treatments with inputs. Dissolved oxygen content was lowest in the feed-chicken manure-16-20-0 combination. Nitrate and nitrite levels were significantly higher in the treatments that received chicken manure (P<0.05); available phosphorus was significantly highest (P<0.01) in the chicken manure-feed combination. There are indications that the phosphorus content of chicken manure increased that in the soil although total phosphorus in the soil contributed only about 0.8% of that in water. The organic matter content of the pond soil was influenced by the various inputs resulting in significantly higher (P<0.01) organic matter content of the sediments in the treatments that received chicken manure, feeds and their combination. There were no significant differences (P>0.05) among the treatments in terms of primary productivity, zoo- and phytoplankton populations and algal biomass. A highly significant difference (P<0.01) among the treatments was observed in terms of chlorophyll a concentration.
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. 121-124.
Arlo W. Fast and Kent E. Carpenter, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, P.O. Box 1346, Kaneohe, Hawaii 96744, USA
Victor J. Estilo and Hernane J. Gonzales, Brackishwater Aquaculture Center, University of the Philippines in the Visayas, Leganes, Iloilo City 5920, Philippines
10 January 1989, CRSP Research Report 89-13
Abstract The effects of pond water depth (0.5, 1.0 and 1.5 m) and artificial circulation on certain pond dynamic processes were evaluated in a factorial design. Deep ponds had more uniform temperatures, with less rapid temperature changes, greater whole pond respiration, and greater temperature and oxygen stratification. Artificial circulation reduced thermal and oxygen stratification. Sediment respiration, which was estimated using a new technique, was more than three times greater than plankton and shrimp respiration combined, regardless of treatment combination. Shrimp yields were not significantly different for any of the six treatment combinations.
This paper has been accepted for publication in Aquacultural Engineering 7: 349-361(1988) .
William Y.B. Chang, Great Lakes Research Division, The University of Michigan, Ann Arbor, Michigan 48109, USA
Hai Ouyang, Pearl River Fisheries Institute, Chinese Academy of Fisheries, Guangzhou, China
20 June 1989, CRSP Research Report 89-14
Abstract Dissolved oxygen dynamics and vertical water circulation in high density integrated fish culture ponds were monitored monthly at 2-h intervals for 26h from March through September at the Pearl River Delta, China. Stable thermal stratification was found almost daily in May through September. Vertical circulation began daily between 8 and 10 p.m. The average depth for this turnover in summer can be as great as 0.7-1 m. Complete vertical circulation occurs only during major storms. A convection turbulence model was used to examine the vertical mixing process and showed that light wind (<100 cm/s) and surface cooling (<2°C) after sunset can substantially influence the depth of mixing.
Photosynthesis by algae is the most important natural mechanism contributing oxygen to ponds; compared to photosynthesis, net oxygen gain and loss due to diffusion during daylight is small. The compensation depth corresponded to twice the Secchi disk depth, ranging from 50 to 80 cm. The dissolved oxygen concentration in the hypolimnion was usually less than 2 mg/l, but increased at night during the period of vertical circulation. Hypolimnion oxygen deficit (HOD) was explored with the in situ dissolved oxygen concentration. HOD was found to increase during the daylight period and decrease at night after destratification.
This paper was published in Aquaculture, 74: 263-276(1988) .
The effect of manures and chemical fertilizers on the production of Oreochromis niloticus in earthen ponds
Bartholomew W. Green and Ronald P. Phelps, International Center for Aquaculture and Alabama Agricultural Experiment Station, Auburn University, Auburn, AL 36849, USA
Hermes R. Alvarenga, Estacion Acuicola Experimental El Carao, Secretaria de Recursos Naturales, Comayagua, Honduras
10 April 1989, CRSP Research Report 89-15
Abstract The effect of weekly applications of similar quantities of nitrogen and phosphorus from three different sources on the production of Oreochromis niloticus (10 000/ ha) was studied in 0.1-ha earthen ponds. Layer chicken litter (500 kg total solids (TS)/ ha), dairy cow manure (1020 kg TS/ ha) and chemical fertilizer (46-0-0 at 30.6 kg/ ha and 0-46-0 at 62.6 kg/ha) were applied weekly. Mean total net production after 150 days was greater with chicken litter (1759 kg/ha). Differences in fish production were explained in terms of net and gross primary productivity and community respiration.
This paper was published in Aquaculture, 76: 37-42(1989) .
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