Several thousand fish along the Verde River just below Horseshoe dam have died. Scientists from the Arizona Game and Fish Department tested the water for bacteria, viruses and parasites.
Every April, SRP drains the Horseshoe reservoir. This year, SRP postponed the draining by two months so it could make repairs to a valve. By the time it was drained, temperatures soared and the waters became very warm, which led to low dissolved oxygen levels.
"Our biologist collected some fish out there and took to our fish health expert and looked at fish...And they had inflamed gills typical when fish are trying to deal with low-oxygen conditions," said Curt Gill who is with game and fish. He says several thousand fish were killed including carp, goldfish, largemouth bass, blue gill and catfish.
As part of its habitat conservation plan through the U.S. Fish and Wildlife service, SRP drains the reservoir to discourage non-native fish from spawning and to make available riparian vegetation so endangered birds can nest.
Marc Wicke is with SRP. HE says there’s always a fish kill when the reservoir is drained. Though he concedes this year’s was considerable.
"All these fish are introduced species," said Wicke. "They are non-native to the Verde River. They’re predatory on native fish. And that’s one of the reasons why our permit has us minimize the number of fish in horseshoe reservoir that are non native."
Wicke says SRP will see if there is any remaining water in the reservoir to flush the decomposing fish away.