DATE: Wednesday, September 3, 1997          TAG: 9709030488

SECTION: LOCAL                   PAGE: B12  EDITION: FINAL 

SOURCE: ASSOCIATED PRESS 

DATELINE: ANNAPOLIS, MD.                    LENGTH:   47 lines

PFIESTERIA MAY THRIVE ON RIVER'S UNIQUE TRAITS, EXPERT THEORIZES

Unique conditions in the lower Pocomoke River may encourage growth of a toxic microorganism attacking fish, a scientist said Tuesday.

The theory, presented to an advisory committee investigating fish lesions and fish kills on the Pocomoke, will help nail down why pfiesteria attacks, said JoAnn Burkholder, a North Carolina State University researcher who first identified the microorganism.

Pfiesteria is linked to two fish kills in August that killed more than 10,000 fish. On Friday, authorities closed indefinitely a seven-mile stretch of the river.

Robert Magnien of the Maryland Department of Natural Resources presented the new theory to scientists from Maryland, Virginia and other states.

The unusual circumstances in the lower Pocomoke suggest the problem is less likely to occur elsewhere, he said.

``But we need to stay vigilant,'' Magnien said.

The lower Pocomoke is shallow, wide and has a slow-moving current that is ideal for a concentration of nutrients that wash downstream and allow algae to bloom.

There is also a high concentration of fish in the lower Pocomoke because of insufficient oxygen upstream, Magnien said.

He said scientists need to examine what's causing the oxygen problem, what role bacteria play, whether scientists should analyze in detail the composition of algae in fish kill and pfiesteria ``hot spots,'' and nutrient levels.

``These kinds of questions are a really good base . . . (and) will help steer scientists to do the most effective research possible,'' Burkholder said.

Donald F. Boesch, who heads the advisory committee, said the hypothesis put forward by Magnien is key because it can lead to solutions.

``This is the first time we see an explanation being put forth of why now, why the Pocomoke,'' Boesch said, adding that the explanations were all plausible.

``I think it's more than a starting point,'' he said.

The advisory committee is not specifically looking at potential threats to human health. Those questions are being examined by a team of doctors studying a group of people who have complained of symptoms that may be linked with pfiesteria such as skin lesions, respiratory problems and short-term loss of memory. KEYWORDS: FISH KILL PFIESTERIA

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