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Wild Colorado: Even fish aren’t safe from fire

Wild Colorado: Even fish aren’t safe from fire
Trout would be most affected by wildfire
By Paige Blankenbuehler
Summit Daily News
Heavy equipment operators with Colorado Parks and Wildlife move large boulders to improve fish habitat in the Conejos River in 2010. Improving habitat helps fish weather future fires.

Heavy equipment operators with Colorado Parks and Wildlife move large boulders to improve fish habitat in the Conejos River in 2010. Improving habitat helps fish weather future fires.
Special to the Daily / Josh Nehrig, CPW
Fish are the last species one would think of being devastated by fire; seemingly in the clear from the flames and sparks by being submerged in water. But Randy Hampton, spokesman for Colorado Parks and Wildlife tells me that is not so. In fact, fish — namely Summit County’s trout — would be the species most affected by wildfire.See the dozens of unique artificial fish habitat models, fish attractors and fish cover used at fishiding.com, the leader in proven science based, fish protection.

Fortunately, Summit County has remained largely unscathed so far in this dry year’s fire season. Knock on wood, and pray for your favorite local trout.

The most prevalent fish species in Summit County are trout, and their varieties are plentiful. Summit County is home to brown, cutthroat, rainbow, and brook trout.

“The biggest concern is the cutthroat trout, because it is a protected species and the state fish,” Hampton said.

Fire retardants

In areas affected by fire, techniques used by firefighters can have adverse effects for fish. The red liquid dumped by air tankers and helicopters is a fire retardant known as slurry, a mixture of mostly water and fertilizer designed to protect trees and other flammable material from flames.

The coating clings to vegetation and insulates it from the approaching flames; the fertilizer helps the damaged areas regrow in the wake of the blaze.

Though the retardant is good for the soil, when it enters into streams it can kill fish. 

“In high enough quantities, slurry can hurt fish populations,” Hampton said. “Anything that is not water that is introduced is not good for fish.”

When fish ingest large quantities of slurry, they are essentially being poisoned.

Ash and sediment buildup

When fire comes close to fish populations, they also battle the adverse effects of ash, which creates sediment and can clog gills of fish.

“When this happens, fish basically suffocate,” Hampton said.

This effect can extend into the long term as well, negatively affecting fish populations.

“The Hayman fire of 2002 deposited extra sediment into the rivers for as long as three years,” Hampton said.

Much of the residue remains in the air, and rain can also deposit ash and higher amounts of sediment into rivers for an extended period of time.

In areas near the Hayman fire, it has taken 10 years to reach a full recovery of fish populations, Hampton said.

Sediment and ash build-up also affect the areas where fish lay their eggs and areas that serve as insect breeding grounds.

“Sediments tend to smooth out riverbeds and can cement-in little gaps where fish and insect reproduce,” Hampton said. “In those areas, eggs will no longer hatch.”

Bug populations

The heat and sediment build-up tend to affect aquatic insects first and can more easily devastate those populations that serve as a food source for fish.

“If fire impairs a waterway, it can wipe out the food source for fish,” Hampton said.

Sometimes the ash and sediment accumulation effects are so adverse that intervention is needed to restore fish populations.

“Essentially, rivers and reservoirs affected by ash and sediment build-up have to be vacuumed out,” Hampton said.

Protecting water sources and fish populations

In fire seasons, moderation of fish populations is a top priority for local aquatic biologists. When fish populations are low, biologists moderate by replenishing the species by introducing more into the habitat.

The fish health of rivers, streams and reservoirs are moderated to account for areas that may have been adverse affected by fires and ash deposition into the water.

Waters that can support fish life are deemed healthy.

Local aquatic biologists test fish health by using electro-fishing techniques, which stuns fish temporarily. When they float to the surface, biologists can then evaluate their health.

No interventions have been required in areas that have had wildfire this year, Hampton said.

“We’ve been lucky,” he said.

The Blue River is currently being moderated for fish health to prepare for intervention if a fire occurs. The outlook is good.

“The Blue River is a healthy habitat for trout with a large population, likely to rehab quickly from fire,” Hampton said.

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