Author(s): Elamin M Elamin, Sheikheldin M Elamin and Zuheir N Mahmoud

Abstract: Pinctada margaritifera is naturally occurring in Dungonab Bay and its adjacent areas. Its growth was studied for an annual cycle, from January to December 2010 in hanging, bottom and ground culturing systems as well as from the wild oysters. The asymptotic shell highest (H∞) was 27.59, 9.55 and 7.77 cm in the hanging, bottom and ground system, respectively. In the wild it was 27.59 cm. The growth Index Ф was 4.39, 3.97 and 3.94 in the hanging, bottom and ground system, respectively. In the wild it was 3.66. The average heights shell increment was 0.80, 0.62 in April and 0.48 cm in March in the hanging, bottom and ground system, respectively. The lowest shell increment was 0.00, 0.09 in August and 0.21cm in the ground, bottom and the hanging system, respectively. The linear plot of H (t +∆t) against H_t, for hanging, bottom, and ground culture system as well as and wild oysters yielded very highly significant correlation (p<0.001; r = 0.969 - 0.997). The linear plot of the relationship between t and -ln (1-Ht /H∞) in all system yielded very highly significant correlation (p<0.001; r = 0.990 - 0.998). In all groups, the increase in shell length with time is slow and variable.

Pages: 550-555  |  477 Views  80 Downloads

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