Effects of integrated combination and quicklime supplementation on growth and pearl yield of freshwater pearl mussel, Hyriopsis cumingii (Lea, 1852)

The effects of integrated combination and quicklime supplementation on growth and pearl yield of a freshwater mussel, Hyriopsis cumingii (Lea, 1852), were examined through a 137-day growout in land-based enclosures. The integrated combinations examined were either mussel, bighead carp and gibel carp or mussel and bighead carp. Each combination was treated either with or without quicklime supplementation. One half of the mussels in each enclosure were grafted with pieces of the mantle epithelium while the other half were not. During the experiment, gibel carp were fed formulated feed while the mussel and bighead carp were fed natural live food. Quicklime was regularly provided in the enclosures as calcium replenishment. The species composition in the integrated system significantly affected growth in shell size and wet weight of the mussels regardless of the graft and pearl yield, while no significant effects of quicklime supplementation were detected. Growth rates in shell size and wet weight of both grafted and non-grafted mussels and pearl yield were slightly higher in the enclosures with mussel, bighead carp and gibel carp than those with mussel and bighead carp, although these differences were not statistically significant. The non-grafted mussel exhibited faster growth in shell size and wet weight than the grafted mussel within the same treatment. Results of the present study indicate that species combination in an integrated system can affect growth and pearl yield of H. cumingii . The species combination of mussel, bighead carp and gibel carp is recommended for commercial H. cumingii farming.