Cold winter culprit in Canyon View fish kill
Winter continues to leave its mark on the Grand Valley.
The prolonged cold blamed for killing trees and rose bushes around the city also is being blamed for a fish kill in the south pond in Canyon View Park on 24 Road.
The kill was reported earlier this week by Rusty Johnson of Grand Junction, who said she regularly spends winter days walking around the park.
“I’ve done it for, oh, six to eight years now,” she said. “But this was the first year I didn’t see an aerator keeping a hole open in the ice.”
“There are big fish and little fish; I’m so distressed,” she said.
Grand Junction Parks superintendent Mike Vendegna said the city investigated the fish kill as soon as it was reported.
“We got on it immediately,” said Vendegna, pointing to the cold winter as the main culprit.
The city normally runs aerators in the ponds to keep them partially open, but the extensive cold played havoc with the aerators, Vendegna said.
“We think it was because of the hard winter and the long cold spell we went through,” he said. “This is the first time we remember the ponds being totally frozen.”
He said the city’s aerators will be back online as soon as possible.
“We had so many problems from the cold this winter,” he said. “I’ve seen lots of trees and rose bushes that didn’t make it.”
Fish kills result when the decay of plant material in the water depletes the oxygen supply.
Unfrozen ponds will retain high levels of oxygen during the winter because oxygen demands for fish and photosynthesis are less in cold water, and oxygen reaches the water through air and wind agitation.
Thin ice may allow enough sunlight for plants to continue photosynthesis.
But when ice and snow cover persists into late winter, sunlight reaching the water is reduced while metabolism and decomposition continue depleting the available oxygen.
Colorado Parks and Wildlife aquatic biologist Lori Martin said the dead fish appeared to be a mix of largemouth bass, green sunfish, bluegill and various species of suckers.
“We don’t manage the ponds, that’s the city, and I wasn’t even sure there were fish in them,” Martin said. “Typically this is the sort of thing you see at high-elevation reservoirs where the snow gets deep and cuts off the sunlight.”
Martin said there could be more such kills around the area this spring as the area’s shallow ponds start to open.
“I think as more and more of the ice starts coming off the ponds and the weather gets warmer, we’ll start seeing more fish kills,” she said.
“I think the inversion we had for such a long time kept things a lot colder a lot longer.”