ARTIFICIAL SELECTION OF SUITABLE HOST FISH AND PARASITIC CYST FORMATION OF GLOCHIDIA IN PINK HEELSPLITTER, POTAMILUS ALATUS

16 different fish species were tested to select suitable host fish for pink heelsplitter, Potamilus alatus. The results showed that transformed juveniles were only obtained from freshwater drum Aplodinotus grunniens, the only suitable host fish for pink heelsplitter, and the average transformed rate was (49.6±9.4)%, and that over parasitic caused mortality of infested fish. It was proven that other 14 freshwater fish species except red drum Sciaenops ocellatus have no potential as host of pink heelsplitter. SEM showed that glochidia could infest on the gill of red drum that belong to the same family as freshwater drum, and form parasitic cyst with faster on large red drum than juveniles. However, the infested red drum showed a rather high mortality rate under the double stress of infestation and low osmotic in freshwater, suggesting that desalination and nutrient intensive cultivation should improve the survival rate of infested red drum. The glochidia detached from yellow catfish, smallmouth bass and blue catfish in 1—2d after infestation almost all died, suggesting that certain larval lethal factors may exist in these fishes. Comprehensive analysis indicated that pink heelsplitter was the most specific Unionidae species for host fish, and the red drum might be the potential host for pink heelsplitter.