Investigation of stock condition of Lengeh pearl oyster Pinctada radiata in Western Hormozgan province habitats with emphasis on ecological agents
Pearling in Northern Persian Gulf has barred since 2006. Population dynamic and investigation of stock condition of pearl oysters has not done in thease area in thease years heretofore. For identification of habitats of Pinctada radiata, mohar oyster, primary sea tours in coastal waters of 11 regions in Lavan Island, 11 regions in hendorabi Island and 6 regions in Nakhiloo and Michaeil Ports, for early survey were done. 2 habitats in Lavan waters and 2 habitats in Hendorabi waters were identified and for investigation of stock condition, were sampled from autumn 2011 to summer 2012, seasonality. Belt transects andrandom quadrates method was used in this sampling. Physicochemical parameters in depth range of thease habitats was evaluated by CTD in first sea tour of stock sampling. Lavan 1 habitat, had maximum area, maximum total stock, maximum CPUA, maximum CPUE and maximum biomass, among other habitats, equal to 60ha, 357000N, 0.6N/m2, 119N/hr and 4620kg respectively. Biometric data in Hendorabi2 habitat was rather than other habitats, significantly (P<0.01). Infinity length, L∞, was calculated in Lavan1, Lavan2, Hendorabi1 and Hendorabi2 habitats, equal to 89.16, 87.68, 86.11 and 86.42 mm respectively. Growth constant, K, was estimated in Lavan1, Lavan2, Hendorabi1 and Hendorabi2 habitats, equal to 0.43, 0.44, 0.47 and 0.56 year-1, respectively. Natural mortality constant, M, was calculated in Lavan1, Lavan2, Hendorabi1 and Hendorabi2 habitats, equal to 0.73, 0.75, 0.78 and 0.88 year-1, respectively. Results of this project showed, area of investigated habitats, oysters stock of them and CPUA, have diminished in thease years, and interdict of pearl oysters catch was not able to revival of stocks. Majority of physicochemical parameters in depth ranges in surveyed habitas, had significant difference (P<0.01). Water turbidity in Hendorabi2 habitat was rather than other habitat, significantly (P<0.01), as subsidiary of high sedimentation in this habitat and main reason of high natural mortality constant, M, low settlement rate and absence of lower scale of oysters length in Hendorabi2 habitat.
Main Authors: | , , , , , , , |
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Format: | Report biblioteca |
Language: | Persian |
Published: |
Iranian Fisheries Science Research Institute
2014
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Subjects: | Physicochemical, Mohar pearl oyster, Pinctada radiata, Stock assessment, Lavan Island Hendorabi Island, Sampling, CPUA, Mortality, Sedimentation, |
Online Access: | http://hdl.handle.net/1834/13584 |
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Summary: | Pearling in Northern Persian Gulf has barred since 2006. Population dynamic and investigation of stock condition of pearl oysters has not done in thease area in thease years heretofore. For identification of habitats of Pinctada radiata, mohar oyster, primary sea tours in coastal waters of 11 regions in Lavan Island, 11 regions in hendorabi Island and 6 regions in Nakhiloo and Michaeil Ports, for early survey were done. 2 habitats in Lavan waters and 2 habitats in Hendorabi waters were identified and for investigation of stock condition, were sampled from autumn 2011 to summer 2012, seasonality. Belt transects andrandom quadrates method was used in this sampling. Physicochemical parameters in depth range of thease habitats was evaluated by CTD in first sea tour of stock sampling. Lavan 1 habitat, had maximum area, maximum total stock, maximum CPUA, maximum CPUE and maximum biomass, among other habitats, equal to 60ha, 357000N, 0.6N/m2, 119N/hr and 4620kg respectively. Biometric data in Hendorabi2 habitat was rather than other habitats, significantly (P<0.01). Infinity length, L∞, was calculated in Lavan1, Lavan2, Hendorabi1 and Hendorabi2 habitats, equal to 89.16, 87.68, 86.11 and 86.42 mm respectively. Growth constant, K, was estimated in Lavan1, Lavan2, Hendorabi1 and Hendorabi2 habitats, equal to 0.43, 0.44, 0.47 and 0.56 year-1, respectively. Natural mortality constant, M, was calculated in Lavan1, Lavan2, Hendorabi1 and Hendorabi2 habitats, equal to 0.73, 0.75, 0.78 and 0.88 year-1, respectively.
Results of this project showed, area of investigated habitats, oysters stock of them and CPUA, have diminished in thease years, and interdict of pearl oysters catch was not able to revival of stocks. Majority of physicochemical parameters in depth ranges in surveyed habitas, had significant difference (P<0.01). Water turbidity in Hendorabi2 habitat was rather than other habitat, significantly (P<0.01), as subsidiary of high sedimentation in this habitat and main reason of high natural mortality constant, M, low settlement rate and absence of lower scale of oysters length in Hendorabi2 habitat. |
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