Effects of Salinity on Bonamia sp. Survival in the Asian Oyster Crassostrea ariakensis

Abstract

Abstract A novel Bonamia sp. discovered in Bogue Sound, NC, has recently emerged as a parasitic threat to the Asian oyster Crassostrea ariakensis. Because this oyster is being considered for introduction to the mid-Atlantic region, more data are needed to better evaluate the risks associated with this parasite. Field observations collected from North Carolina and information on other Bonamia spp. suggest an affinity for higher salinities, and direct transmissibility; in the absence of explicit experimental tests, however, this is largely hypothetical. Consequently, we used laboratory trials to test the direct transmissibility and the persistence of Bonamia sp. in infected triploid C. ariakensis transferred to and maintained at three salinities, 10, 20, and 30 psu for at least 15 wk. Under these experimental conditions, there was no evidence of direct Bonamia sp. transmission. Average parasite intensity in infected oysters transferred to and maintained at 10 and 20 psu decreased compared with oysters place...