blake
Life Member
NEWS:
From the Iowa DNR:
Drop in Oxygen Level Kills Fish in Spirit Lake
SPIRIT LAKE - An estimated 500 to 600 walleyes were found dead along the southeast shoreline of Spirit Lake on Thursday.
Mike Hawkins, fisheries biologist for the Spirit Lake district, said the investigation points to a sag in the level of dissolved oxygen. This can be caused by decomposing vegetation or algae, lack of wind, and elevated water temperatures. Dissolved oxygen typically reaches its lowest levels early in the morning before plants begin to produce oxygen.
"Oxygen sags can happen very rapidly and small fish are vulnerable because they can't escape quickly enough," said Hawkins. The fish hatchery draws water in the area where the fish kill occurred and has noted lower oxygen levels over the past few days coming in to the hatchery.
The dead walleyes were mostly 4 to 5-inch fish produced this year, but there were a few small adults mixed in. There were a few thousand of 1 to 2-inch yellow perch, Johnny darters and northern logperch that were also killed.
A local resident notified the DNR that they saw dead fish along the shore Thursday. Hawkins said this is in no way related to the wastewater release last week on the southwest shoreline of Spirit Lake. "That leak turned out to be very small and was stopped immediately," he said.
Hawkins says that even though hundreds of walleyes were killed during this event, it will not negatively impact the population.
From the Iowa DNR:
Drop in Oxygen Level Kills Fish in Spirit Lake
SPIRIT LAKE - An estimated 500 to 600 walleyes were found dead along the southeast shoreline of Spirit Lake on Thursday.
Mike Hawkins, fisheries biologist for the Spirit Lake district, said the investigation points to a sag in the level of dissolved oxygen. This can be caused by decomposing vegetation or algae, lack of wind, and elevated water temperatures. Dissolved oxygen typically reaches its lowest levels early in the morning before plants begin to produce oxygen.
"Oxygen sags can happen very rapidly and small fish are vulnerable because they can't escape quickly enough," said Hawkins. The fish hatchery draws water in the area where the fish kill occurred and has noted lower oxygen levels over the past few days coming in to the hatchery.
The dead walleyes were mostly 4 to 5-inch fish produced this year, but there were a few small adults mixed in. There were a few thousand of 1 to 2-inch yellow perch, Johnny darters and northern logperch that were also killed.
A local resident notified the DNR that they saw dead fish along the shore Thursday. Hawkins said this is in no way related to the wastewater release last week on the southwest shoreline of Spirit Lake. "That leak turned out to be very small and was stopped immediately," he said.
Hawkins says that even though hundreds of walleyes were killed during this event, it will not negatively impact the population.