green algae contains large amounts of carbon and 

 nitrogen. Large blooms and their subsequent decay could 

 significantly alter the carbon and nitrogen in the estuary. 

 Such alterations could in turn upset the production and 

 abundance of fish and shellfish. 



The researchers: 



Hans Paerl, Institute of Marine Sciences, University of 



North Carolina at Chapel Hill 

 Donald Stanley, Institute for Coastal and Marine 



Resources, East Carolina University 

 Robert Christian, Department of Biology, East Carolina 



University 



Two costly diseases 



The problem: contaminated shellfish and red-sore 

 disease in fishes 



Contaminated shellfish and disease-ridden fish are lost 

 resources to North Carolina's fishermen. Fishermen are 

 prohibited from harvesting contaminated oysters and 

 clams. And fish stricken with diseases such as red-sore 

 usually die or are unsellable to seafood processors. 



Shellfish contaminated by discharges from sewage 

 treatment plants, faulty septic systems, land run-off and 

 boat waste discharges can carry serious viruses. Hepatitis 

 A is one of the most serious viruses they transmit. Last 

 year in the state of New York, forty people contracted 

 hepatitis A after eating contaminated clams. Another 

 300 to 400 people came down with gastroenteritis. After 

 finding a portion of the clams harvested from approved 

 open waters, state health officials warned New Yorkers 

 not to eat any raw shellfish. While the outbreak was 

 limited to New York state, officials from the Center for 

 Disease Control believe outbreaks may be occurring in 

 other areas, yet going unreported. 



The research: studies into how shellfish are con- 

 taminated with hepatitis A and how fish are afflic- 

 ted with red -sore disease 



Being surrounded by vials of cultivated viruses might 

 make some folks nervous, but for Mark Sobsey it's part 

 of the job. Sobsey has been conducting Sea Grant studies 

 into the detection, occurrence, survival and fate of en- 

 teric viruses and bacteria in shellfish since 1976. But his 

 latest project focuses on a single virus — hepatitis A. 



After a stint at the National Institute of Health in 

 Bethesda, Md., Sobsey brought back to his Chapel Hill 

 laboratory the ability to cultivate and assay hepatitis A. 

 Until 1979 such cultivation was impossible and Sobsey's 

 laboratory will be one of the few in the country capable 

 of cultivation. 



With his new knowledge in hand, Sobsey will be study- 

 ing hepatitis A contamination in oysters and clams. He 

 will be testing current detection methods to see if they 

 accurately determine the levels of hepatitis A in shellfish 

 and in the waters and sediments of their habitat. Scien- 

 tists, including Sobsey, have questioned the accuracy of 

 the present methods used to detect viruses in shellfish. 



Levels of hepatitis A in shellfish may depend on how 



much contamination is present in the water. Sobsey will 

 be measuring this relationship as well as the relationship 

 between levels of hepatitis A and other viruses and bac- 

 teria in the water and sediment. 



Sobsey also wants to find out how fast oysters and 

 clams take up and eliminate hepatitis A. Oysters and 

 clams will cleanse themselves of contamination if they 

 are placed in clean water. But factors such as water tem- 

 perature and salinity may affect their rate of cleansing. 



One hope for fishermen may be depuration plants 

 where large quantities of contaminated oysters and clams 

 can be placed in tanks of clean water to free themselves 

 of their contaminants. Sobsey will be setting up a pilot- 

 scale depuration system to study hepatitis A elimination. 



While Sobsey concentrates on contaminated shellfish, 

 Ed Noga will be studying red-sore disease in the fishes of 

 the Albemarle Sound. Fisheries officials estimate that up 

 to 20 percent of the commercially important fishes in the 

 Albemarle Sound may be affected by red-sore. 



Noga wants to find out what causes red-sore in fishes 

 and what characteristics, either in the fish or its habitat, 

 indicate an impending outbreak of the disease. 



Learning more about red-sore could mean finding ways 

 to control its outbreak. And the study will be the first 

 step in building a veterinarian ability in this state to deal 

 with the problems of disease in fish. 



The researchers: 



Mark Sobsey, Department of Environmental Sciences 

 and Engineering, University of North Carolina at 

 Chapel Hill 



Ed Noga, School of Veterinary Medicine, North Carolina 

 State University 



Photo by Neil Caudle 



Mark Sobsey with bottled virus 



