Improved pearl quality and survival rate of operated-shells by using 1-year-old mother-shells of the pearl oyster, Pinctada fucata martensii
2008
Iwanaga, S.(Nagasaki-ken. Inst. of Fisheries (Japan)) | Hirai, M. | Hosokawa, H.
To improve the management of pearl culture, the production efficiency of mother-shells of difference ages was examined in Tsushima Island, Nagasaki Prefecture from June 2004 to January 2006. The survival rate, quality, value of production and price of pearls produced from 1-year-old oysters inserted 6.66 mm nuclei (1-year-old group) were compared with those from 2-years-old oysters inserted 7.27 mm nuclei (2-years-old group 1) and 2-years-old oysters inserted 7.42 mm nuclei (2-years-old group 2). Oysters in the 2-years-old group 2 were from the same group as the 1-year-old group, but nuclei were inserted in June 2005. The survival rate of the 1-year-old group was 32.0% and 12.7% higher than those of the 2-years-old groups 1 and 2, respectively. The nacre thickness and rations of faultlessness and commercially valuable pearls produced from the 1-year-old group were 1.6 times and 2.2 times, 12.3% and 13.7%, 21.9% and 20.0% higher than those from the 2-years-old groups 1 and 2, respectively. The prices of 7 and 8 mm commercial pearls from the 1-year-old group were 1.3-3.4 times higher than those from the 2-years-old groups 1 and 2. The value of commercial pearl produced from the 1-year-old group was 2.6 times and 1.9 times higher than those from the 2-years-old groups 1 and 2, respectively. Above results suggest that using 1-year-old oysters for operation in June can be effective in improving the production efficiency of pearl culture.
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