 Southsea pearls on the other hand are farmed in larger molluscs, and keshi from these may reach considerable size and value.Freshwater cultivators in pre-1985 Japan commonly used up bits of active mantle tissue left over from in-body bead nucleation by slipping a few keshi into the mantle.Now the market of those keshi farmed in China is so low that they discard the leftovers rather than expending even a tiny fraction of their mussels' strength on producing freshwater keshi.