Culture-based fisheries in non-perennial reservoirs of Sri Lanka: influence of reservoir morphometry and stocking density on yield |
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| Authors: | U A D JAYASINGHE & U S AMARASINGHE & S S DE SILVA |
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| Institution: | Department of Zoology, University of Kelaniya, Kelaniya, Sri LankaSchool of Life and Environmental Sciences, Deakin University, Warrnambool, Vic., Australia |
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| Abstract: | Abstract Culture-based fish yield in non-perennial reservoirs of Sri Lanka was related to reservoir morphometry and stocking density. The reservoirs were stocked mainly with fingerlings of one Chinese and three Indian major carp species, common carp, Cyprinus carpio L., and the genetically improved farmed tilapia strain of Nile tilapia, Oreochromis niloticus (L.), at four pre-determined species combinations and a range of stocking densities SD (fingerlings ha?1)]. Twenty-three reservoirs were harvested successfully at the end of the culture period of 2002–2003. Basic limnological and morphometric parameters, including shoreline development ( D L ) and shoreline area ratio ( R LA ), were estimated for each of the 23 reservoirs. Bray–Curtis similarity and non-metric multidimensional scaling using mean values of limnological data revealed that reservoirs could be ordinated into two major clusters, one with intact sample distribution due to similar trophic characteristics and the other with scattered sample distribution. Reservoirs in the cluster with similar trophic characteristics showed significant correlation ( P < 0.05) between R LA and total fish yield ( Y ). A multiple regression equation, Y = ?693 + 4810 R LA + 0.484 SD , was generated to estimate fish harvest in relation to SD . |
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| Keywords: | culture-based fisheries limnology non-perennial reservoirs reservoir morphometry shoreline stocking density |
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