By Tracy Overstreet
tracy.overstreet@theindependent.com

Fisheries biologist Brad Newcomb said when human-induced fish kills occur, standard practice is to calculate the value of the fish and charge that value to the violator.

The money is then used for fish restocking programs, he said.

There's a standard value for fish based on size and species.

In Grand Island's recent kill of more than 10,600 fish, the predominant species was carp. Newcomb said the standard value for common carp is 40 cents a pound.

The carp ranged in size from less than a pound to 12 pounds.

Although Newcomb is still working on the official total of the fish value, which he expects to have completed next week, he said a simple estimate shows that the value will be in the thousands.

Using an average 3 pound weight, times the 40 cents per pound with 8,700 carp killed, the replacement cost for that species alone is $10,440.

Newcomb said the kill numbers are conservative because the Wood River and Platte River had good flow at the time of the discharge violations and there was a rain the weekend of the violations, which increased flows even more.

Many of the carcasses were thought to have already washed downstream, washed into undetected areas or been picked up by predators such as skunks and raccoons, Newcomb said.

He also believes the fish population was lower to begin with.

"It was not as healthy a population to begin with because of long-term water quality problems," Newcomb said. "I noticed the diversity of the population was low."

Nebraska Department of Environmental Quality field data specialist Dave Bubb said the oxygen levels in the water were exceptionally low when he tested the city's wastewater treatment plant outfall ditch and sections of the Wood River and Platte River.

His initial belief is that the fish literally suffocated in the water.

The city of Grand Island issued a written statement Wednesday that oxygen levels in plant discharges were low and caused the fish kill.

It pledged to take "full responsibility" for compliance and said it would take any and all measures necessary to cease violating its discharge permit.

The city's oxygen-depleted discharges were attributed to an overload of the city systems by the neighboring meatpacking plant JBS Swift & Co.

No cleanup of the carcasses was planned. Newcomb said nature will take care of the carcasses and hopefully the fish population will recolonize as fish upstream move into the area.

"It pretty much wiped out most of the fish in that stretch," he said.