Effect of Sizes on Acceptance of Implantation Tissue in Freshwater Mussel Cristaria plicata for Non-Nucleated Pearl Production

The Cristaria plicata are large size freshwater mussel clams and is an endemic species of Thailand, the inner shell is shiny and beautiful with thick mantle tissue, therefore has sufficient potential for producing freshwater pearls. The aim of this study was to investigate the effect of three different mussel sizes (7-9 cm, 9.1-12 cm, and larger than 12 cm) on production of pearl from graft tissue. The experimental mussels were reared in an earthen pond with stagnant water condition.  The results showed that there were no statistically significant differences in length, survival rate, and mean (Mean + S.D) pearl sac formation (78.30 ± 0.57%, 81.60 ± 1.80% and 78.30 ± 0.57%) of the mussels among the sizes at the end of the experiment ( p .>0.05). However, growth in weight differed significantly where the highest mean weight gain (3.91 ± 0.51 g) was found in medium size mussel while mean weight gain in large and small size mussels were 2.08 ± 0.51 and 0.58 ± 0.51 g ( p ≤0.05). This study shows that C. plicata can live in stagnant water in ponds and can be used to produce freshwater pearls. Therefore, there should be studies of environmental factors suitable for growth and the quality of freshwater pearls produced, and should study the breeding of C. plicata for commercial freshwater pearls production. Keywords : freshwater mussel ; Cristaria plicata ; freshwater pearl