Abstract
Studies of oysters, Crassostrea virginica, collected from 10 sites in the Caloosahatchee River and Estuary, Florida, revealed a varied parasite and symbiotic faunae that have never been reported in this area. Organisms observed included ovacystis virus infecting gametes at four sites (prevalence <1%), ciliate protozoans Ancistrocoma sp. in the gut of a stressed oyster at one site and Sphenophrya sp. infecting the gills of animals at three sites (prevalence <1%). The gregarine protozoan Nematopsis was found at all 10 sites (prevalence 24% to 90%) and oysters at some sites had concurrent infections of Nematopsis prytherchi and Nematopsis ostrearum in connective tissue near the stomach, mantle, and gills. Light to moderate infestations of hydrozoan polyps of a species in the genus Eutima were observed in the gills of oysters at all sites (prevalence 1% to 22%). Helminths included an unidentified turbellarian (prevalence 1% to 4%) observed at three sites and the digenetic trematodes Echinostoma sp., Proctoeces maculatus and Bucephalus sp. in oysters at five (prevalence 1% to 93%), three (prevalence >1%), and six (prevalence 1% to 3%) sites respectively. The first two trematodes were found infesting the gonoducts of their hosts while sporocysts of Bucephalus sp. infected connective tissues and gonads. Metacestodes of a species in the genus Tylocephalum were found in vesicular connective tissues near the gut, mantle, and in the gills of animals at all sites (prevalence 7% to 58%). Many sites had oysters with multiple infestations/infections of the above organisms indicating a rich biotic diversity, especially at those sites least impacted by human activity.