Cultured pearls have an important place in international trade. The Vedas, the Bible, and the Koran all mentioned pearls, and they are regarded as one of the highest honours. Pearls are generated in nature when an irritant, such as a sand grain or a parasite, is swept into the pearl molluscs and lodged within it, where it is coated with micro-layers of nacre, a lustrous substance made up of 80–90 per cent aragonite crystals of CaCO3. The ICAR-Central Institute of Freshwater Aquaculture (CIFA), Kausalyaganga, Bhubaneswar, India, has created a base technology for cultivating pearls in freshwater habitats, recognising the scope and value of freshwater pearl production. Indian pond mussel, Lamellidens marginalis is the major species used in freshwater pearl aquaculture. In addition, ICAR-CIFA has pioneered a novel feature of freshwater pearl farming. The Institute has also taken the lead in disseminating freshwater pearl culture technology to the country’s fish farming communities, entrepreneurs, researchers, and students to build a sustainable model for the country’s socio-economic development. In this chapter, we will briefly cover pearls and their types, their historical significance, the spread of pearl mussels of freshwater origin in various countries, pearl biomineralisation, pearl farming techniques, and factors affecting pearl quality, among other things.

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An on-farm study with periphyton based culture systems was conducted for 90 days in 16 m 2 soil-based and fertilized out-door cement tanks. The objective was to evaluate the effect of provision of feed and orientation of substrate on the water quality and taxonomic composition and biomass of periphyton and free plankton. Fertilization of tanks was done with cattle dung applied at 4.5 t/ha, followed by single super phosphate (SSP) and urea, each at 50 kg/ha. Fortnightly fertilization schedule included cow dung at 2.25 t/ha, urea and SSP, both at 50 kg/ha each. The treatments consisted of tanks receiving no feed and no substrate (NFNS), receiving only feed (FNS) and those receiving only sugarcane bagasse as periphyton substrate at 2 t/ha (3.2 kg/tank) either vertically suspended in water column (NFSV) or applied to tank bottom (NFSB).Fish in three tanks of FNS treatment were fed daily at 5% of body weight with a 25% crude protein pelleted feed. Fingerlings of Labeo fimbriatus were stocked at 10,000/ ha 10 days after manuring. The percentage weight gain of fish was 425.08

Lamellidens marginalis (Lamarck, 1819) is one of the important candidate species for freshwater pearl production in India. In the present study, the length-weight, width-weight and height-weight relationships of L. marginalis maintained in the farm were examined from January 2015 to September 2016. Monthly sampling was carried out and a total of 1015 specimens were analysed for the study. The length-weight, width-weight and height-weight relationships derived were W = 0.0003L2.712, W = 0.0018L2.708 and W = 0.0.0293L2.210 and the value of r2 was estimated as 0.776, 0.619 and 0.597 respectively. The values of b indicated the relative growth in body weight and superior physiological condition of the mussel. The length-weight, width-weight and height-weight relationships were found to be positive allometric and better correlation was observed in length-weight and width-weight relationships.