Microbe may not be lone culprit in fish kill
Creek where menhaden died had little oxygen at bottom
By Molly Murray
Sussex Bureau reporterJuly 12, 2000
The News JournalDAGSBORO - A single cell resembling the microbe Pfiesteria was found in a preliminary test of water taken Monday from Pepper Creek.
But, Pfiesteria, if present, many not have been the only problem 50,000 to 75,000 Atlantic menhaden ran into when they schooled into Pepper Creek Monday and died.
State scientists found high levels of dissolved oxygen near the surface and almost no oxygen at the bottom of the creek - a situation that can be lethal to fish, said Roy Miller, a state fisheries biologist. Similar conditions were found during a massive menhaden kill last week in Bald Eagle and Torquay Canal at the north end of Rehoboth Bay.
Department of Natural Resources and Environmental Control officials also found high counts of red tide algae, Gyrodinium instriatum, in Pepper Creek, Miller said. The algae may have been what made the water in Pepper Creek a mahogany brown during and after the kill. The algae deplete oxygen in the water.
Various types of Gyrodinium algae were linked to three fish kills in the Inland Bays in 1998.
"It has been forming major blooms in the Indian River," Miller said. Pepper Creek flows into Indian River.
As state officials await more complete test results - possibly as early as today - they continued to advise people to avoid contact with the water in Pepper Creek. Boating is fine but water-skiing, swimming and other activities where there is direct contact should be avoided.
Pfiesteria has been linked to skin sores and neurological disorders in people exposed to the microorganism when it is in its toxic form.
"If we get confirmation there were no Pfiesteria cells, that will be pretty strong, compelling evidence to scale down on the advisory," Miler said.
On Tuesday, few people used Pepper Creek.
"I know that the river's awful quiet," said Timothy Timmons, who lives off Pepper creek.
Timmons said he had not seen many dead fish.
Miller said a trawl survey done Tuesday found dozens of live fish, including four menhaden. Two of those had sores that were healing, he said.
About 5 percent of the dead menhaden found Monday had suspicious sores resembling those seen in Pfiesteria-related kills, Miller said.
University of Delaware College of Marine Studies researcher David Hutchins said he would not be surprised if Pfiesteria is found in the Pepper Creek samples.
"We find it throughout the Inland Bays. We find it in Delaware Bay. We find it in Roosevelt Inlet," said Hutchings, part of a team that has developed a probe to detect Pfiesteria. "It is a normal member of the marine community around here."
Hutchins, an assistant professsor of oceanography, also has been looking at the conditions that change the microbe from benign algae-eater to fish killer. He said he would test samples from Pepper Creek provided by the state.
"My guess is the Pfiesteria is taking advantage of these low-oxygen events" when fish are already dead and dying, he said.