Tilapia cage culture and water quality in Lake Taal Philippines /
Alcañices, Marilyn M.
Tilapia cage culture and water quality in Lake Taal Philippines / by Marilyn M. Alcañices - Diliman, Quezon City : University of the Philippines Diliman, 1997. - viii, 75 pages : illustrations ; 28 cm.
Thesis (Master of Science in Environmental Science) University of the Philippines
Includes bibliographical references.
Water quality of Lake Taal in Batangas, Southern Luzon, Philippines, was assessed and compared in areas with tilapia cage culture and without cage from March 1996 through February 1997. Three stations were considered in the northern basin of the lake namely: Balas, station 1 which serves as control (non- cage area), Sampaloc and Berinayan, as station 2 and 3 (cage areas) respectively.
Water samples with two replicates were collected monthly using a van Dorn sampler at 0,5, 10,15 m depths in all stations. Below surface water from inside the cage was also collected. Water temperature, water transparency, pH, and conductivity were determined in situ. Dissolved oxygen, chloride, NOs, NH, PO, and Total-P were analyzed in the laboratory. Phytoplankton density and algal biomass through chlorophyll and light-and-dark bottle method was used to measure primary productivity.
Results show that conductivity and DO were significantly different between non-cage and cage areas. Conductivity was significantly different (P=0.0148) between control and cage area during the wet season (May to October 1996). Highest conductivity value (2100 1S cmt) was observed in July in a cage area (station 3). Mean values of DO gave significant differences (P=0.0256) in the different stations throughout the study period. A decrease of DO to 2.5 mg L-! was observed below 10 m depth around the cage areas in February.
Analysis indicates that oxygen depletion occurred in the water column in cage areas. The presence of cage structures decreases the flow rate resulting in weak circulation thus, decrease the supply of oxygen and slows down the removal of toxic waste metabolites from the vicinity of the fish farm. The decay of organic matter on the sediment under the cage may also cause localized oxygen deficiency in cage areas.
The impact of cage culture in Lake Taal appeared to be minor but can alter lake ecosystem if not properly managed. Proper zoning of fish cages and continuous water quality monitoring are needed.
Tilapia--Culture--Phlippines--Taal lake (Batangas
Water quality--Philippines--Taal Lake (Batangas)
639 / Al1 1997
Tilapia cage culture and water quality in Lake Taal Philippines / by Marilyn M. Alcañices - Diliman, Quezon City : University of the Philippines Diliman, 1997. - viii, 75 pages : illustrations ; 28 cm.
Thesis (Master of Science in Environmental Science) University of the Philippines
Includes bibliographical references.
Water quality of Lake Taal in Batangas, Southern Luzon, Philippines, was assessed and compared in areas with tilapia cage culture and without cage from March 1996 through February 1997. Three stations were considered in the northern basin of the lake namely: Balas, station 1 which serves as control (non- cage area), Sampaloc and Berinayan, as station 2 and 3 (cage areas) respectively.
Water samples with two replicates were collected monthly using a van Dorn sampler at 0,5, 10,15 m depths in all stations. Below surface water from inside the cage was also collected. Water temperature, water transparency, pH, and conductivity were determined in situ. Dissolved oxygen, chloride, NOs, NH, PO, and Total-P were analyzed in the laboratory. Phytoplankton density and algal biomass through chlorophyll and light-and-dark bottle method was used to measure primary productivity.
Results show that conductivity and DO were significantly different between non-cage and cage areas. Conductivity was significantly different (P=0.0148) between control and cage area during the wet season (May to October 1996). Highest conductivity value (2100 1S cmt) was observed in July in a cage area (station 3). Mean values of DO gave significant differences (P=0.0256) in the different stations throughout the study period. A decrease of DO to 2.5 mg L-! was observed below 10 m depth around the cage areas in February.
Analysis indicates that oxygen depletion occurred in the water column in cage areas. The presence of cage structures decreases the flow rate resulting in weak circulation thus, decrease the supply of oxygen and slows down the removal of toxic waste metabolites from the vicinity of the fish farm. The decay of organic matter on the sediment under the cage may also cause localized oxygen deficiency in cage areas.
The impact of cage culture in Lake Taal appeared to be minor but can alter lake ecosystem if not properly managed. Proper zoning of fish cages and continuous water quality monitoring are needed.
Tilapia--Culture--Phlippines--Taal lake (Batangas
Water quality--Philippines--Taal Lake (Batangas)
639 / Al1 1997