The Arkansas Game and Fish Commission is faced with finding an explanation for the 80,000 to 100,000 fish that washed up dead on the shores of the Arkansas River last week.
Game and Fish spokesman Keith Stephens told msnbc.com it would likely take about a month to determine the cause of the large-scale fish death.
The fish were discovered Thursday by a tugboat operator in a 20-mile segment of the river near the city of Ozark.
One day later, as many as 5,000 birds dropped dead in Beebe, Arkansas, about 125 miles away from Ozark. Scientists are pointing to a possible lightning storm or high-altitude hail as the source of that mystery.
Nearly all of the dead fish – about 95 percent – were identified as drum fish, leading experts to believe the mass kill was caused by a species-specific disease.
“If it was from a pollutant, it would have affected all of the fish, not just drum fish,” Stephens said.
Drum fish are bottom feeders and are not desirable to fishermen. Stephens said the commission is not planning a cleanup but will allow birds and raccoons to take care of the mess.
“So far, the evidence does not suggest that pollution contributed to either the bird or fish kill,” said David Lyons, the head of a local chapter of the Sierra Club, according to msnbc.com. “If the test results indicate that contaminants were responsible, then local environmental groups will likely have several questions and concerns about the two events.”