Practical water chemistry for fishfarmers I. Teaching strategies
Abstract
Years of ambitious, yet seemingly futile, efforts by the authors in the Philippines in making fishfarmers comprehend and appreciate chemical reactions the way chemists do, paved the way for the formulation of teaching strategies that communicate water chemistry. Theoretical concepts, being well understood, served as a springboard for farmers in translating abstract ideas into field situations. Laboratory practicals become less intimidating as standard laboratory glasswares and material were replaced by day to day material within the farmer s easy reach.
Source
In: Hirano, R., Hanyu, I. (eds). The Second Asian Fisheries Forum. Proceedings of the Second Asian Fisheries Forum, 17-22 April 1989, Tokyo, Japan. Manila, Philippines: Asian Fisheries Society. pp. 789-792
Publisher
Asian Fisheries SocietyType
Conference paperCollections
- Conference Proceedings [283]
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Book chapter
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Conference paper
Impact assessment of cage culture in Lake Taal, Philippines
- In Conservation and Ecological Management of Philippine Lakes in Relation to Fisheries and Aquaculture: Proceedings … Seminar-Workshop held on October 21-23, 1997, INNOTECH, Commonwealth Ave., Diliman, Quezon City, Philippines, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center; Philippine Council for Aquatic and Marine Research and Development (PCAMRD), Department of Science and Technology; Bureau of Fisheries and Aquatic ResourcesThe environmental impact of cage culture on water quality of Lake Taal was assessed from March 1996 through February 1997. Three stations were considered namely: Balas, which serves as station 1 (non-cage area) and Sampaloc and Laurel, stations 2 and 3 (cage areas), respectively. Monthly water samples with two replicates were collected using a van Dorn sampler at 0, 5, 10 and 15-m depths in all stations. Below surface water from the inside of the cages was also collected. Water temperature, water transparency, pH, and conductivity were determined in situ. Dissolved oxygen, chloride, NO3, NH3, PO4, and total P were analyzed in the laboratory. Phytoplankton density and algal biomass (through cholorophyll a) and primary productivity indices were determined with the light-and-dark bottle method. Of the water quality parameters, conductivity and DO had significant differences between non-cage and cage areas. Conductivity gave significant difference (P<0.01) between control and cage area during the wet season. Highest conductivity value (2100 µ S/cm) was observed in station 3. Mean values of DO gave significant differences (P<0.05) in the different stations throughout the study period. A decrease of DO to 2.5 mg/1 was observed below 10-m depth around the cage areas. Analysis indicates that cage culture leads to oxygen depletion in the water column. The presence of cage structures decreased the flow rate resulting to weak circulation. The reduced water circulation in effect decreased the supply of oxygen and removal of toxic waste metabolites from the vicinity of the fish farm, and reduced the supply of plankton. These results suggest that the impact of cage culture in Lake Taal is minor but can alter the lake ecosystem if not properly managed. Zoning and continuous water quality monitoring are needed. -
Article
The growth, survival and production of shrimp (Penaeus monodon) cultured with green mussel (Perna viridis) in semi-intensive ponds
-UPV Journal of Natural Sciences , 1997 - University of Philippines in the VisayasThe culture of tiger shrimps (Penaeus monodon) with and without green mussels (Perna viridis) was compared in terms of animal growth, survival, production, and pond water quality. Tiger shrimps (2.6 g) were stocked at 50,000/ha in six 1,000 m2 earthen ponds. Green mussels (mean shell-on weight of 11 g) were stocked at 100,000/ha on ropes suspended from bamboo rafts in three of these ponds. The growth and survival of tiger shrimps were not significantly different when cultured with or without mussels. Higher shrimp production (1,528.2 kg/ha) was obtained when these were cultured with mussels than without (1,327.5 kg/ha). Water quality did not vary significantly between treatments but ponds with both shrimp and mussel had lesser algae, lower biological oxygen demand and particulate organic matter levels, and generally higher morning dissolved oxygen concentrations compared with ponds without mussels. Results show the potential of green mussels as biological filters in shrimp ponds.
