Prevalence of Perkinsus marinus (Dermo) in Crassostrea virginica along theConnecticut shoreline

The prevalence of Perkinsus marinus in the eastern oyster Crassostrea virgi nica along the Connecticut shoreline was surveyed during a period of 2 year s from 1996 to 1997. The survey was conducted in shallow and deep waters. F ifty-four samples involving 1430 oysters were tested. Using Ray's Fluid Thi oglycollate Medium, the parasite was found at all sampling locations with a prevalence range from 10% to 100%. The weighted prevalence values were sig nificantly greater in shallow waters compared to deep waters in 1996 (t-tes t, P < 0.05). However, in 1997, the difference between the two areas was no t significant. The results demonstrated P. marinus had established enzootic s throughout the Connecticut shoreline. Oyster aquaculture practices of tra nsplanting natural seed from shallow waters to approved areas found in deep er waters had probably resulted in comparable weighted prevalence values be tween these areas. (C) 2000 Elsevier Science B.V. All rights reserved.