Investigation on the host specificity of the glochidium of freshwater pearl mussel, Hyriopsis (Limnoscapha) myersiana (Lea, 1856)

Abstract

The reproduction cycle and the host specificity of the freshwater pearl mussel, Hyriopsis (Limnoscapha) myersiana were studies from April 1990 to May 1991. Marsupia were found already in early November but, the peak occurred between December and January. The glochidia will emerge from late November till early March. In the laboratory, mussel took less than 24 hours to release all the glochidia. The experiment on host specificity of the glochidia on the fry of 11 species of fish was carried out, using 4 levels of glochidium concentration. The mortality of the fish after infection was plotted against these exposure levels. After 30-days, the interpolated LE [subscript 50] values (exposure concentration of glochidia that killed 50% of the fry) for Iridescent mystus (Mystus vittatus), Striped catfish (Pangasius sutchi), Yellow mystus (M. nemurus), were 15,000, 20,000, 50,000 respectively. The mortalities were very low in Striped tiger nandid (Pristolepis fasciatus) and Temminck’s kissing gourami (Helotoma temmincki). The most resistant were Sand Goby (Oxyeleotris marmoratus) and Striped tiger nandid, which also gave the highest production of juveniles. Species of Rasbora were not resistant at all, all specimens died soon after infection.