What caused High Rock fish kill?
By Scott Jenkins
Thousands of dead fish littered the shores of a cove off High Rock Lake on Tuesday.
The sight left some who live in the area worried about what might have caused it.
But while the man charged with protecting the Yadkin River for a nonprofit organization said he believes it can be linked to a massive sewage spill in Thomasville earlier this year, state water quality officials say they investigated and found no evidence that is the case.
It was more likely a natural occurrence, they say.
Residents discovered fish blanketing the shoreline next to the Fisherman’s Cove community off St. Matthews Church Road. David Lineberry, who lives nearby, heard Sunday about dead fish there but didn’t realize the magnitude of the kill until he went to the cove Tuesday morning to net bait for fishing.
“Wasn’t no use throwing a net in there to try to catch no bait, because it wasn’t there,” Lineberry said.
Fish small and large lay dead along the shores on both sides of the cove and others remained scattered across the water’s surface. Lineberry said they included shad, brim, crappie, carp and suckers.
Called to the scene Tuesday morning, Dean Naujoks, the Yadkin riverkeeper, estimated the number could be hundreds of thousands on the shore and said many more had probably already sunk to the bottom of the cove.
He noted that while smaller fish typically can’t escape areas quickly robbed of dissolved oxygen, larger, heartier fish normally can swim to better waters and survive. “What concerns me about this is we have a huge variety of fish, which is very rare,” Naujoks said.
Lineberry and girlfriend Penny Shaver said they had seen nothing comparable since a drought devastated the lake in 2002.
“We hadn’t never seen fish like this die,” said Shaver, who has lived near the cove her entire life. “It’s weird.”
Naujoks said he believes the kill is connected to a 15.9 million gallon sewage spill that occurred upstream in Thomasville.
The spill, which Thomasville reported in early August, had been going on for several weeks into North Hamby Creek, which feeds into High Rock Lake. Naujoks said raw sewage made its way into High Rock, likely settling into the sediment near the High Rock dam.
Dr. JoAnn Burkholder, a water quality expert at N.C. State University, said at the Yadkin Riverkeeper annual meeting Friday a sewage spill the size of Thomasville’s would settle and could linger on the lake bottom for up to six months before new sediment covers it.
But something ó it could be rain and wind or human activity, Naujoks said ó could disturb the water and churn up the sewage, which could rob the water of oxygen and kill the fish, Naujoks said. He said that’s probably what caused the kill.
“There’s no way to prove it … but in my opinion, when you have a sewage spill of 15 million gallons, it’s going to rob this lake, which is already struggling, of oxygen, and it likely contributed to this fish kill.”
But Susan Massengale, a public information officer for the N.C. Division of Water Quality, said a state investigator tested the water in the cove and elsewhere on the lake Tuesday afternoon and found no evidence that spilled sewage had caused the fish kill.
“There’s no indication wastewater was part of the mix at all,” she said.
Massengale said instruments used to test water quality can measure several indicators to determine the presence of an unusual chemical, waste or other substance. But she said none of those indicators led the investigator to believe any substance contributed to the death of the fish.
The measurements, she said, seem to bear out what a Wildlife Resources Commission officer who saw the kill told water quality officials ó that nature was most likely to blame.
The cove where the fish kill occurred is a relatively small, shallow body of water separated from a larger cove by a culvert beneath a bridge on St. Matthews Church Road. It’s the type of body where calm weather can allow water to form layers, with low dissolved oxygen at the bottom, Massengale said.
But changing temperatures and storms ó both of which Rowan has experienced in recent days ó can cause “turnover” in the water.
“When that happens, low dissolved oxygen goes through the entire water column for a period of time,” Massengale said. “Fish may have been swimming in a richer oxygen level at the top of a small area when either a storm or change in temperature happened and they got caught in a low oxygen situation.”
Division of Water Quality readings indicate the fish kill was caused by “just one of those turnover events,” she said.
Naujoks may be hard to convince.
“It’s not something that just happened,” he said at the cove, standing on a pier overlooking shorelines covered in dead fish that people approaching the shore could smell long before they saw them. “There’s no connection to anything.”
The state fined Thomasville $35,000 for the sewage spill. The town has also appropriated more than $140,000 to investigate its cause.