**9. Summary**

280 Aquaculture

A; Light microscopy of early juvenile (after transformation, 0-day-old) shell, note shell hinge (sh). B; SEM micrograph of 1-day-old juvenile, appearance in anterior region of new soft periostracum (pe), note glochidium shell (gs). C; Juvenile 10 days old, anterior (a) region appears before and grows more than the posterior (p), note growth line (gl). D; Light microscopy of development of shell, 40-day-old juvenile, note foot (f), gill (g), posterior adductor muscle (pa). E; Light microscopy of development of shell, 50-day-old juvenile, note anterior wing (aw); posterior wing (pw). F; SEM of ventral side of 50 day-old juvenile. G; Light microscopy of external morphology of 90-day-old juvenile, note excurrent siphon (es), incurrent siphon (is), umbo (u). H; Light microscopy of external morphology of 140-day-old juvenile, note rectum (r). I-L; External morphology of shell, 160, 180, 270 and 360 days old, respectively.

Fig. 6. Morphological development of 0–360-day juveniles of *Hyriopsis* (*Limnoscapha*)

*myersiana*. (Kovitvadhi et al., 2006; 2007).

Culture of freshwater pearl mussel is divided into the three consecutive steps: (1) culture of glochidia larvae in artificial media, (2) rearing juveniles and (3) rearing adult. The results of several studies indicate that glochidia in some species of freshwater mussel could be cultured in artificial media containing mixtures of M199, common carp plasma, antibiotics and antimycotic, and could have fully developed adult and gametogenesis was complete. The important factors in juvenile culture included culturing systems, water quality, substrate (sand) and food. The laboratory-scale recirculating aquaculture system, which water quality change was rather stable and sand could attached materials for food such as organic matter or microorganisms. Furthermore, the juveniles can burrow into the sand as they do in nature, and this helps them to prevent the attachment to the shell of feces and pseudofeces with many protozoa and later flatworms and eventual death of the juveniles. However, the size of sand should appropriate for each size of the juvenile. Phytoplankton was a vital source of nutrients, which has suitable size and shape to move into the mouth of the juveniles so that juveniles can digest them. Prior to transfer to outdoor, mussel organs have to fully developed for ingesting food, particularly gills, the incurrent and excurrent siphon, and their shells must close completely. Moreover, the water quality and food were also important factors to growth and survival.
