DAO 40:67-78 (2000)  -  doi:10.3354/dao040067

ABSTRACT: Pteriid oysters (Pinctada maxima, Pinctada margaritifera, Pinctada albina, Pteria penguin), rock oysters (Saccostrea glomerata, Saccostrea cuccullata, Saccostrea echinata) and representatives of other taxa (Malleidae, Isognomonidae, Pinnidae, Mytilidae, Spondylidae, Arcidae) from the wild, and 4670 hatchery-reared P. maxima, from northern and Western Australia, were examined for parasites and diseases. Rickettsiales-like inclusions and metacestodes of Tylocephalum occurred in most species. Intranuclear virus-like inclusions occurred in 1/415 wild P. maxima, 1/1254 S. cuccullata, 3/58 Isognomon isognomum, 1/80 Pinna bicolor and 1/45 Pinna deltodes. Perkinsus was histologically observed in 1/4670 P. maxima spat, 2/469 P. albina, 1/933 S. glomerata, 16/20 Malleus meridianus, 12/58 I. isognomum, 1/45 P. deltodes, 5/12 Spondylus sp., 1/16 Septifer bilocularis and 3/6 Barbatia helblingii. One of 1254 S. cuccullata was heavily systemically infected with Perkinsus merozoites, meronts and schizonts, and was patently diseased. Other potentially serious pathogens included Haplosporidium sp. in 6/4670 P. maxima spat, Marteilia sydneyi from 1/933 S. glomerata, and Marteilia sp. (probably M. lengehi) (1/1254) and Haplosporidium sp. (125/1254) from S. cuccullata. The latter were associated with epizootics on offshore islands, with heaviest prevalence (45%) in oysters with empty gonad follicles. Marteilioides sp. infected the oocytes of 9/10 female S. echinata from Darwin Harbour. Details of geographical distribution and pathology are given, and the health of the bivalves examined is discussed.

KEY WORDS: Bivalves · Australia · Marteilia · Marteilioides · Haplosporidium · Perkinsus · Distribution