Determining of suitable size of paraffin image for image pearl production in freshwater mussel (Lamellidens marginalis) in Bangladesh

Abstract

An experiment was carried out to produce image pearl from February 2016 to September 2016 in freshwater mussel (Lamellidens marginalis) of 9-10cm length. This experiment was set to find out the suitable size of paraffin image for better quality image pearl production by inserting different size of paraffin image. A total of five hundred mussels were operated with paraffin image of different size 3.5cm (T1), 3cm (T2), 2.5cm (T3), 2cm (T4), and 1.5cm (T5) by netbag hanging method in cistern and pond of Freshwater station, BFRI research complex, Mymensingh. The stocking density of operated mussel was 100 per decimal. Physicochemical parameters of the culture pond (Temperature, DO, Alkalinity, pH, Ammonia, Calcium, and Phytoplankton) were recorded at 15 days interval and found in a suitable range for mussel culture. Operated mussels were observed monthly to know the survival rate. After 8 months of culture survival rate of mussel was observed highest in treatment T3 (49%) followed by T4 (21%), T5 (19%), T2 (16%), and T1 (13%), respectively. Image pearl formation with high luster and nacre layer 0.47±0.01mm was found premier from treatment T3 whether the nacre layer was found 0.23±0.02 mm, 0.31±0.01 mm, 0.41±0.01 mm, and 0.43±0.01 mm from T1, T2, T4, and T5 respectively. A thick nacre layer, the shiny luster of image pearl with a high survival rate of mussel was found in treatment T3. In that case, it can be said that 2.5 cm size of paraffin image is suitable for image pearl culture in the freshwater mussel.