Survey of Oyster Diseases in Aransas Bay - Survey of Oyster Populations and Associated Organisms

Abstract

Mortalities among oysters (Crassostrea virginica) in Aransas Bay were surveyed by use of tray-held oysters at two locations. Live and gaping oysters found during the study were fixed with Zenker's Fixative and shipped to Dr. J. G. Mackin of Texas A&M University for disease analysis. Field data collections and Dermocystidium marinum checks were made by personnel of the Texas Parks and Wildlife Department. Three distinct mortalities appeared during the study period of January 1963 through June 1964. These occurred in March-May 1963, October-December 1963, and in April-June 1964. The mortality in March, April, and May 1963 depleted to original stock of oysters at both stations. In August 1963, the stations at Pintail Reef and Half Moon Reef were restocked with 2,000 oysters each. The two subseqent mortalities had depleted this stocking by June 1964. Dermocystidium marinum checks made throughout the study period showed relative low incidence ratings during mortality periods and did not indicate that D. marinum was the primary mortality agent. Identification and information pertaining to the mortality agent will be presented in a later report by Dr. J. G. Mackin.