Hundreds of fish found dead at Lower Glidden Lake

BURKE — Following numerous reports of deceased fish being found along the banks of Lower Glidden Lake earlier this week, officials with the Idaho Department of Fish and Game believe that water conditions may have caused the large "fish kill."

IDFG Regional Fishery Manager Andy Dux explains that the reports were confirmed by the agency on Wednesday.

"One of our staff visited the lake (Wednesday) and he was able to determine that we definitely had a fish kill up there…it looks to be a few hundred fish that died."

Before the dead fish had been seen, the worry was that something had affected some of the 940 rainbow trout that had been stocked into the lake by IDFG on Sept. 30. Upon further examination though, it was discovered that the affected fish were both rainbow and brook trout of various ages. Because of this, Dux believes that the kill and the stocking event occurring so close together is just a coincidence.

As to what caused the fish kill, IDFG can rule out sickness or pollution.

"It's a little difficult to say," Dux said of determining the cause. "I visited with our fish health lab…and at this point, it doesn't seem likely that this was any kind of disease outbreak."

Due to the sudden nature of the deaths and how it affected multiple species, odds are that it had something to do with a sudden change in conditions within the lake.

Dux states that the most likely cause is either "lake turnover" and/or an algae bloom lowering oxygen levels.

"At the end of summer, when you have that warm surface layer of water and cold water down below, that surface layer starts to cool in the fall and eventually the density of those two layers of water becomes similar," Dux explained. "…when that happens, it's possible that we had a change in dissolved oxygen levels."

Despite the timing of the Panhandle Health District announcing on Thursday that Cave, Black and Hauser lakes were suffering from a blue-green algae bloom — no evidence of that was found at Lower Glidden.

Looking forward, recreators and anglers of Lower Glidden should rest easy, as this doesn't appear to be something that will happen with any regularity.

"It's most likely a one-time event that isn't going to lead to any long-term issues," Dux said. "We don't have any history of this in Lower Glidden, so nothing there suggests that this is going to be an ongoing problem."

If everything stays as it should be, IDFG will continue to stock the lake with fish on its normal schedule — which is slated for early 2022.