Climate-induced fires worsen the danger to fish in distress

By JOHN FLESHER and BRITTANY PETERSON

September 21, 2022 GMT

AMALIA, NM (AP) – Biologist Bryan Bakevich unscrewed the top of a plastic bucket and removed a merciless Rio Grande trout that twisted from its grip and fell to the grassy bank of Middle Ponil Creek.

“He wants to go home,” Bakevich said, slipping the fish into the narrow, cold stream – the last leg of a three-month, 750-mile (1,207-kilometer) odyssey to this ruthless and 107 more plucked in June by a another stream in mountainous northern New Mexico.

The largest fire ever recorded in the state had broken out dangerously near their previous home, setting fire to trees and undergrowth on nearby slopes. The summer monsoon season was approaching and heavy rains could sweep the ash mud into the creek, obstructing the fish’s gills and suffocating the gravel bottoms where they feed and lay their eggs.

State and federal crews rushed to the rescue, using electric fishing gear to stun and catch as many ruthless as possible. They were transported south to Las Cruces and kept in tanks at New Mexico State University until Middle Ponil Creek was ready to accommodate them.

Today, wildlife agencies in the southwestern United States consider missions like this essential as climate change leads to more frequent and warmer fires, fueled by prolonged drought and tree-killing insect infestations. Particularly vulnerable are the ruthless Rio Grande trout and the gila trout, rare species found mainly in small, high-altitude streams.

“With each fire, more of their populations are affected,” said Jill Wick, head of the native fish program for the New Mexico Department of Game and Fish. “Their habitat has often disappeared, swept away by the stream. There is no place where they can hide and cool off. Their food is also decimated ”.

The danger is growing elsewhere. Tens of thousands of salmon, trout and other fish died in August when a flash flood hit a burnt area in Northern Californiasending a plume of mud into the Klamath River.

Trout numbers have dropped by up to 80% in Colorado’s sections of the Cache la Poudre River after floods and landslides in summer 2021, a survey found. The largest fire in the state’s history had burned 326 square miles (844 square kilometers) in that area the previous year.

LOCATION MATTERS

Fire doesn’t always hurt fish. Many species have evolved to take advantage of the “bias and diversity” that fires bring to landscapes and waterways, said Dan Isaak, a fishery scientist with the US Forest Service in Idaho.

The one-two punch of fire and torrential rain is less common in the northern regions. Ash tends to stay sheltered from winter snow and creeps into the ground or drips into streams during the spring thaw. Provides nutrients for algae eaten by insects which become fish food. Burnt trees fall into streams, creating puddles and reeds for feeding and spawning.

But further south, larger and larger fires incinerate so much foliage that they hold the ground in place that heavy debris flows cause large algae blooms that can suffocate fish.

Their health also depends on surrounding features such as slope slopes, plant life, and soil types, said Christopher Clare, a habitat conservation biologist at the Oregon Department of Fisheries and Wildlife. And, Clare said, climate change is warming waterways, a problem made worse when fire steals shoals of shade trees.

Rebecca Flitcroft, a U.S. Forest Service fish biologist in Corvallis, Oregon, modeled the danger a fire poses to the Chinook salmon and bull trout source in Washington’s Wenatchee River system that feeds the Columbia River.

Although both species are endangered, the findings suggest that trout are worse off because they occupy isolated, cold springs. The intensity of the fire is greater than the lower portions of Chinook’s preferred river systems for easier access to the Pacific, Flitcroft said.

Man-made changes to waterways and landscapes make it more difficult for fish to survive during and after fires, he said. The diversions of the water have reduced the habitat. Low levels caused by drought, as well as culverts, roads and dams, prevent fish from escaping to cooler places.

“We are at a tipping point right now with very intense fires, combined with highly disturbed systems that do not allow for connectivity and movement,” said Flitcroft.

Thumbnail of the Youtube video

(Video AP / Brittany Peterson)

CUT IN PROBLEMS

The Rio Grande cutthroat, New Mexico’s state fish, has been in decline for some time. Drought and dams have disrupted its habitat. Non-native brook and brown trout, bred for sport fishing, compete for food. Introduced the rainbow trout crosses with the cutthroat, diluting its genetics.

Named after the reddish cuts under the lower jaw, the ruthless colored occupies about 12% of its historic range in New Mexico and Colorado, according to a 2019 study that predicted continued decline.

New Mexico had 92 ruthless Rio Grande populations earlier this year.

The U.S. Fish and Wildlife Service in 2014 rejected a petition to put the cutthroat on the federal endangered list, but it was overruled by a federal judge and is reconsidering. The nonprofit Center for Biological Diversity had sued for the designation, saying the trout “was barely lurking.”

But a list could involve land use restrictions that many would find unpopular, said Toner Mitchell, New Mexico water and habitat coordinator for Trout Unlimited.

“There is a risk of demonizing or criminalizing the Rio Grande cutthroat,” Mitchell said. “This could involve anything from vandalism to direct efforts to exterminate fish, when in general longtime residents appreciate them.”

Teams have rescued the merciless trout and gila from New Mexico streams more than two dozen times since the late 1980s.

“Before these mega-fires, there could be one or two populations in distress at the same time,” Wick said. “Now, that’s two or three times more.”

Nine ruthless streams were inside the Calf Canyon-Hermits Creek fire this summerwhich started as two fires set to clear the undergrowth but went out of control, consuming more than 530 square miles (1,373 square kilometers).

Ash has wiped out at least the cutthroats of a creek. The trout was rescued by three others. Among them was Rito Morphy, a winding tree-lined stream in the Sangre de Cristo mountain range.

Not all 190 fish there have survived the stress of two road trips and a months’ stay in the university tanks. But the effort remained alive until a new habitat could be prepared at Middle Ponil Creek, about 58 miles from Rito Morphy.

This required poisoning the rainbow trout in the section of the stream where the fish would be placed. “We want to make sure the cutthroat remains genetically pure,” said US forestry biologist Alyssa Radcliff.

It’s ecologically important to preserve a rare fish strain, Radcliff said. Another goal is to make it more available to fishermen. “Many people were brought by grandparents and grandmothers to these streams to catch these fish,” he said.

FINALLY FREE

On a recent sunny and windy afternoon, a pickup truck pulled up along a dirt road in Carson National Forest. Workers collected four- to eight-inch (10 to 20 centimeters) long cutthroats from a large refrigerator into several five-gallon (19-liter) buckets, tied them to backpacks, and dragged them across a lawn to the creek-studded stream. bushes and boulders.

When the buckets were tipped into the stream, the released fish darted through the clear water and wagged their tails in the sandy bottom. Their new digs extended from the creek’s headwaters to a wire and rock barrier 8 miles (12.8 kilometers) downstream to keep rainbow trout out.

It was a quick end to a summer-long mission, said Bakevich, the state’s native fish supervisor.

“After doing all the hard work and coming here,” he said, “this is the best part.”

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Flesher reported from Traverse City, Michigan.

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Follow John Flesher on Twitter: @JohnFlesher.

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The Associated Press’s climate and environmental coverage receives support from several private foundations. Find out more about the AP climate initiative here. The AP is solely responsible for all content.

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