Scientists Study Causes & Effects 



T h 



. he hot, still days of summer 

 have arrived. Vacationers may flock to 

 our beaches for sun and surf, but just a 

 few miles inland, conditions in our 

 brackish waters are ripening for fish 

 kills and Pfiesteria piscicida. 



Pfiesteria made national 

 news last year when it was 

 discovered in tributaries of the 

 Chesapeake Bay, killing 

 thousands of fish and forcing 

 closure of two rivers. Large 

 kills in North Carolina in 1 99 1 

 and 1995 also corresponded to 

 the organism's presence. 



Considerable hype and 

 attention have since been 

 focused on Pfiesteria, but we 

 still don't know precisely what 

 causes these kills and what 

 impact they have on human 

 health and seafood. The 

 process of scientific discovery 

 can be slow. But we're a few 

 steps closer to the answers 

 thanks to recent reports from four teams 

 of scientists assembled by North 

 Carolina Sea Grant. In 18-month 

 studies, these teams examined how 

 Pfiesteria affects the health of crabbers 



By Jeannie Faris Norris 



in fish-kill areas, the learning ability 

 in laboratory rats and the quality of 

 seafood taken from kill waters. A fourth 

 team examined how the nutrients that 

 seep and spill into state waterways affect 

 one of Pfiesteria 's nontoxic life stages. 



Large fish kills have heightened public concern 

 about Pfiesteria and water quality. 



Some facts are already known. 

 Pfiesteria-Mke organisms have been 

 found in coastal waters from Delaware 

 Bay to the Gulf of Mexico. Recent 

 research suggests there are as many as 



four species. The complex life cycle of 

 the organism has at least 24 distinct 

 stages that range from a sediment- 

 dwelling cyst to a free-swimming 

 zoospore. Certain stages may release 

 toxins that affect the neural and 



immune systems of fish. They 

 also directly or indirectly cause 

 fish skin to blister and slough 

 off, creating sores that are then 

 invaded by opportunistic 

 pathogens such as bacteria and 

 fungi. 



Because this unusual 

 organism has raised questions 

 about human health, consumer 

 safety and water quality, the 

 N.C. Department of Environ- 

 ment, Health and Natural 

 Resources (now the Department 

 of Environment and Natural 

 Resources) set aside funds for 

 studies of Pfiesteria-\\ke 

 organisms. North Carolina Sea 

 Grant administered the funds 

 and awarded them to scientists at Duke 

 University, East Carolina University, 

 North Carolina State University and 

 the University of North Carolina at 

 Chapel Hill. 



16 HIGH SEASON 1998 



