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PDF
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Type:
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Conference Paper |
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Author:
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Tan, Reynaldo L.; Higuchi, Teizo; Honma, Tetsushi |
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Conference:
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Common Property in Ecosystems Under Stress, the Fourth Annual Conference of the International Association for the Study of Common Property |
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Location:
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Manila, Philippines |
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Conf. Date:
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June 16-19, 1993 |
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Date:
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1993 |
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URI:
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https://hdl.handle.net/10535/5587
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Sector:
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Fisheries
Water Resource & Irrigation |
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Region:
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East Asia |
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Subject(s):
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fisheries
fishing gear
water resources
ecology
IASC
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Abstract:
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"The main concern of this study is two-fold: to improve the efficiency and productivity of cage culture operation of Tilapia in Sampaloc Lake and to provide practical bases for reassessing the Laguna Lake Development Authority (LLDA) Fishery Zoning Plan. Primary data consisted of surveys of fishcage farmers operation in 1986 and 1990. Results of regression analysis showed that fish size at harvest, stocking density and feeding rate affect yield significantly. Moreover, due to the shift to more intensive feeding, the issue of overcrowding can be ignored and locational advantage plays a minor role. However, it was empirically confirmed that feeds were being applied in excess relative to the prevailing stocking density. At the prevailing technology, the optimal stocking density was found to be 19 times higher than the actual average of about 20 fingerlings/ sq. m. This optimum stocking density was compared to the stocking densities in other countries and it turned out to be relatively moderate. Technical investigation of the cage size-stocking density relationship showed that the carrying capacity of a cage varies primarily with its size. A stochastic frontier total cost function employing translog functional form was used in measuring the levels of inefficiency of the individual cage farmers and the average inefficiency level was found to be 14%. Cage size, stocking density and culture length tend to affect inefficiency the most and the prevailing average yield level, only about 15% of the existing average cage size is needed to produce it. Thus, the 15-ha fishcage belt limit being imposed by LLDA can be met without necessarily dislocating any of the fishcage farmers in the lake."
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