Getting a handle on Pfiesteria

Fish kills: Cleaning up runoff pollution doesn't need to wait for more organism tests.

March 15, 2000

DEPENDING on your viewpoint, single-cell Pfiesteria piscicida may or may not be the primary culprit in Maryland's summer fish kills.

Other possible causes of these outbreaks, such as lack of oxygen in water, were cited by scientists at a Pfiesteria conference held in Annapolis last week.

But researchers noted that Pfiesteria, which destroys fish in its virulent stage, was always present in seven major fish kills in Maryland in the past three years, a strong sign of causal association.

And recent studies have also linked the rapid multiplying of Pfiesteria, the so-called "cell from hell," with higher levels of animal manure in the water.

Higher levels of farm runoff, whether manure or chemicals, cause other harmful effects in the Chesapeake Bay and its tributaries. They spur excess algae production, which depletes oxygen in the water and suffocates fish and other aquatic organisms.

Whether Pfiesteria is finally pinpointed as the primary cause of fish kills, or merely an opportunistic contributor, the challenge remains to reduce pollution running off land into the bay. There's no need to wait until the definitive smoking gun is found.

Agriculture is the greatest single source of that runoff pollution. Maryland enacted a 1998 law to require farmers to develop environmentally sound nutrient (manure, fertilizer) management plans. A series of statewide meetings on the regulations has concluded and the final rules are expected by early summer. They give farmers time to draft and implement approved plans; many have already started the process.

Farmers continue to chafe at the imposition of mandatory nutrient management plans, but it is the only way to assure effective and equitable implementation of this vital plan to clean up the bay.

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