fi eld notes 



Phantom Algae Sends Scientists Sleuthing 



Scientists have never seen 

 anything quite like this. 



It's a microscopic algae that 

 stalks fish, kills them, feeds on their 

 decaying flesh and then retreats 

 to the bottom, waiting for its 

 next victim. 



Sea Grant researchers 

 JoAnn Burkholder and Ed 

 Noga are blaming this mysteri- 

 ous new "phantom" algae for 

 several massive fish kills that 

 have occurred in North 

 Carolina's coastal rivers and 

 sounds. 



Burkholder and Noga are 

 "almost positive" that this 

 strange microscopic plant is a 

 new species. 



"There's no documented 

 case in the literature anywhere 

 in the world of an algae 

 exhibiting this kind of behav- 

 ior," Burkholder says. "It's one 

 of several newer species that 

 have been showing up in recent 

 years." 



Besides its fish-killing traits, this 

 new algae has shown several other 

 startling characteristics: 



• It is a waterborne algae but can 

 live at least 35 days without water. 



• Its cystic "shell" is not pen- 

 etrable by a 100 percent solution of 

 sulphuric acid. 



• It has been known to live at 

 least two years in its dormant stage 

 without sustenance. 



• It has only one known natural 

 enemy, a microscopic protozoan that 

 eats it slowly. Yet, the algae can 

 make an incredible change, turn itself 

 into an amoeba and eat its enemy. 



• The new algae does not 

 accumulate in fish or shellfish 

 muscle, but is known to accumulate 

 in a fish's liver and other organs. Its 



effects on humans are not known. 



• It can live equally well in fresh 

 water or in salt water and can kill fish 

 at a wide range of water temperatures. 



A newly discovered "phantom" algae 



• It can kill crabs and some 

 shellfish if they happen to be in the 

 area when the algae activates its 

 toxins. 



In non-lethal concentrations, the 

 algae could be making fish weaker 

 and more susceptible to other dis- 

 eases, like ulcerative mycosis, the red 

 sore disease. 



Noga's recent work focuses on 

 finding a cause and cure for red sore, 

 which has devastated fish populations 

 in the state for many years. 



The newly discovered organism 

 is closely related to the red tide algae 

 that invaded some Tar Heel fishing 

 waters about four years ago. The new 

 algae could have preceded its red tide 

 cousin by several years. 



The algae has remained "hidden" 



because no one had done serious study 

 of the fish kill problem in the Pamlico 

 and Neuse rivers until Noga began his 

 work. 



The new algae has been 

 associated with as many as 25 

 percent of the major fish kills in 

 the two rivers since 1986. 



In February, the algae was 

 blamed for fish kills at a fresh- 

 water aquaculture facility near 

 Plymouth and in tanks at the 

 N.C. Aquarium at Pine Knoll 

 Shores. The algae also caused 

 fish kills in tanks at the N.C. 

 Maritime Museum and the 

 National Marine Fisheries 

 Service in Beaufort. 



The two scientists realize 

 their work with this strange new 

 algae won't be finished until they 

 come up with a way to control it, 

 to keep it from killing again. 



Burkholder says the secret 

 to controlling the species could 

 lie in simply getting a handle on 

 the quality of coastal waters. The new 

 algae seems to thrive in phosphorous- 

 rich waters and areas loaded with 

 unnatural amounts of nutrients. 



"This is speculative at this point, 

 but I believe that if we could reduce 

 nutrient levels we could control it, 

 help the situation, probably discour- 

 age growth of the organism," 

 Burkholder says. 



Because it seems to thrive on 

 poor quality waters, the algae may not 

 be unique to North Carolina, she says. 

 It may be active in other East Coast 

 waters such as the Chesapeake Bay. 

 And scientists have discovered similar 

 algae in the New England states. 



"It's a bizarre thing," Burkholder 

 says. "It's killing more fish every day. 

 We've got to find some way to stop it." 



C.R. Edgerton 



COASTWATCH 17 



