Widespread fish kills have been reported in 15 North Carolina coastal rivers and lakes; the state Wildlife Resources Commission predicted this week that the trend will continue, perhaps for weeks.
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An investigation is underway, but biologists said in an Oct. 4 report that they believe the deaths are due to flooding produced by Hurricane Florence, which brought up to 35 inches of rain to some parts of the state.
Their conclusion is that fish kills “will persist for several more weeks,” said the report.
Among the best known of the fish kills is one reported Sept. 23 by the Charlotte Observer, involving thousands of fish spread across Interstate 40 in Pender County. Firefighters used hoses to push the fish off the road after the floodwater receded, the Observer reported.
“These fish kills, while unfortunate, are naturally occurring events that typically follow a major hurricane,” said a statement issued by Chad Thomas, the commission’s coastal fishery supervisor.
The cause is not floodwater contaminants or pollution, the state report said. It’s a lack of oxygen in the water and it has spread beyond rivers to streams, canals, lakes and even private ponds, officials said.
The same phenomenon occurred after Hurricane Irene in 2011 and Hurricane Isabel in 2003, state officials said on NCWildlife.org.
“Flood waters associated with Hurricane Florence inundated vast areas of swamp habitats that were naturally much lower in dissolved oxygen,” said the report. “As water levels recede, a flushing effect occurs. The result is a significant drop in dissolved oxygen in the main stem rivers and creeks.”
The fish trapped in such areas “became lethargic,” then gasped at the surface of the water before dying, said the report.
Thomas says the problem will resolve itself only after “water levels return to normal and water temperatures begin to cool.”
“These coastal systems are resilient and with time, the fish populations in the impacted waters will recover, as they did after Hurricane Irene in 2011,” Thomas said in a statement.
Fish kills have been reported along some of the largest rivers in eastern North Carolina, including the Cape Fear, Lumber River, Waccamaw River and Neuse River, said in the release.