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Tilapia cage culture and water quality in Lake Taal Philippines / by Marilyn M. Alcañices

By:

Alcañices, Marilyn M [author]

Material type: Text

TextLanguage: English Publication details: Diliman, Quezon City : University of the Philippines Diliman, 1997.Description: viii, 75 pages : illustrations ; 28 cmContent type:

text

Media type:

unmediated

Carrier type:

volume

Subject(s):

DDC classification:

639 Al1 1997

Online resources:

Click here to view thesis abstract and table of contents

Abstract: 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.

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Holdings ( 1 )
Title notes ( 4 )

Holdings
Item type	Current library	Collection	Call number	Materials specified	URL	Status	Notes	Date due	Barcode
Theses / Manuscripts	Ladislao N. Diwa Memorial Library Theses Section	Non-fiction	639 Al1 1997 (Browse shelf(Opens below))		Link to resource	Room use only	T-5950		00009626

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.

Submitted to the University Library 08/04/2020 T-5950