Until a couple of years ago, anglers who hoped to make the Idaho Department of Fish and Game’s record book wound up killing the state’s grandest fish, based on a requirement that weights of all record-setters be confirmed on a certified scale.

But Boise sportsman Dylan Smith likes knowing the state-record lake trout he recently caught in Payette Lake, located near McCall, is still out there for someone else to reel in.

In 2016, Fish and Game launched a new program enabling anglers to receive recognition for the whoppers they catch and measure, but then toss back. To qualify for a catch-and-release record, an angler must submit a photograph of a trophy fish beside a clearly visible tape measure. A statement from a witness is also preferable, and objects of verifiable length can be used for comparison in lieu of a tape measure.

Smith’s record lake trout, caught on July 21, was 41.5 inches long — 2 inches longer than the prior catch-and-release lake trout record, set by Tom Henson.

Smith, a 27-year-old engineer who graduated from Rexburg-based Brigham Young University-Idaho, said he always releases his catches, unless they’re an undesirable species, such as carp. Smith believes the catch-and-release program is wise, given the pressure of Idaho’s rapidly growing population on its fisheries.

“I think this program is fantastic because it promotes catch-and-release,” Smith sad. “We have really, really good fishing here — some of the best in the nation — and I believe we’ve got to protect that resource that we have.”

Fish and Game has continued keeping records for fish that are harvested and weighed. Martin Koenig, the department’s sport fishing coordinator, said the record lake trout by certified weight was caught in 1971 out of Priest Lake in Northern Idaho, weighing 57.5 pounds and measuring 49 inches long.

Koenig said some of the earliest certified-weight records date back to the early 1900s, and the program was “going in earnest” by the 1940s.

However, many certified weight records have become static, as the state has implemented restrictions on harvesting species such as bull trout, white sturgeon, wild chinook salmon and wild steelhead trout.

In addition to opening the door to “fresh records” on fish species governed by harvest restrictions, Koenig said, “There are a lot of anglers who would love to have their names in record book but haven’t been able to participate because they would rather release trophy fish than have to kill it and weigh it on a scale.”

The list of catch-and-release records is linked to the department’s web page, idfg.idaho.gov. Rather than replacing old records with new record fish, the department maintains the full history so visitors to the site can see the progression toward larger trophies.

Certified-weight records are printed every three years when the state’s fishing regulations are updated. Koenig doubts the next regulations pamphlet, scheduled for release in 2019, will include catch-and-release records, which are changing too frequently.

Koenig said Eastern Idaho fisheries — especially American Falls Reservoir, reaches of the Snake River, Bear Lake and Henry’s Lake — have been hotbeds for trout records.

Smith landed his record lake trout while fishing with a friend and his brother, from the new boat his wife recently bought him as a birthday gift. They’d moved to deeper water to fish near the lake’s bottom amid the mid-day heat, when a large mass appeared on the fish finder. The hulking trout struck his brother’s bait first. Twice, his brother failed to set the hook before the fish ultimately “snarfed up” Smith’s lure. The fight lasted about 15 minutes.

“About 30 feet down, I could see as it was coming up,” Smith said. “Everybody on the boat started freaking out because it was so much larger than expected.”

Smith was poised to release the largest lake trout of his career when his brother suggested it could be a record and advised that he take a quick photo and measurement. Smith admits he packed a tape measure that morning as an afterthought.

Smith plans to frame a photograph of the trout, along with a certificate he’ll soon receive from Fish and Game.

“The main thing was the memory I made catching that fish with my brother and my friend,” Smith said.

AMERICAN FALLS — The Snake River’s banks were littered with several species of dead trophy fish when David Raisch floated the reach below American Falls Dam throughout Saturday.

“I observed multiple sturgeon that were just gasping for air, including some that were 5 feet long,” said Raisch, who works as a fly fishing guide with Palisades Creek Lodge.

Sources with the Idaho Department of Fish and Game say hundreds of trout, small-mouth bass and yellow perch and at least 10 sturgeon were victims of a fish-kill spanning from the dam to the Vista boat ramp and Pipeline area. It was apparently triggered when dissolved oxygen levels plummeted from late Thursday to early Friday.

Fish and Game officials anticipate delayed mortality may continue throughout the next few days.

The cause of the oxygen drop remains under investigation, but sources with the Idaho Department of Environmental Quality have a theory, which is supported by Fish and Game biologists. Lynn Van Every, DEQ’s regional water quality manager, said a prolonged period of hot and calm weather likely resulted in a layer of warm water trapping colder water devoid of dissolved oxygen. Strong winds within the reservoir likely blew the warm water layer upstream from the dam, allowing only the cold water to enter the dam’s penstocks — large pipes that feed Idaho Power turbines.

The cold-water surge lowered oxygen levels below the dam to the point that fish began to die. Van Every confirmed Idaho Power met the conditions of its permits to operate the dam and won’t be fined.

“It happened in relatively short order,” Van Every said. “It’s not uncommon to have low dissolved oxygen coming through, but it sort of happened in a hurry.”

Raisch fished the same reach on Friday night. Though he considered it odd that he had no bites, he didn’t notice the fish-kill until the following morning. He contacted Fish and Game to report the fish-kill after his Saturday float, also describing how surviving trout and smallmouth bass acted “as if they’d had a stroke.”

“It’s a heart-breaker,” Raisch said. “It takes a long time to build those good resources and trophy fishing.”

Dave Teuscher, regional fisheries manager with Idaho Fish and Game, said sensors within the dam and 150 yards downstream constantly monitor dissolved oxygen content, which is considered healthy for fish at levels of above 5 milligrams per liter. Teuscher explained the sensors detected levels dropping from 5 milligrams per liter to zero from 10 p.m. Thursday to midnight Friday. The sensors automatically triggered a blower to activate and oxygenate water flowing from the first penstock. A second blower activated when dissolved oxygen levels hadn’t sufficiently recovered a few minutes later. Ultimately, an alarm signaled Idaho Power staff to respond and open a spillway to add more oxygen.

“Everything Idaho Power has in their water-quality requirements occurred, and that was helpful because this thing could have really turned into a larger fish-kill if that hadn’t happened,” Teuscher said.

DEQ responded to the scene on Sunday, and a Fish and Game crew conducted analysis on Monday morning. On Tuesday afternoon, Fish and Game staff manned a boat, scouring for dead sturgeon to gather biological data, such as growth rate and age.

Some of the sturgeon that were killed were in excess of 30 years old, Teuscher said. The department started stocking them in the reach in the 1980s for catch-and-release fishing and has been stocking the river upstream from American Falls to Idaho Falls more recently.

Idaho’s sturgeon are considered a species of greatest conservation need.

Though Idaho Power was in compliance with its license and obligations to operate the hydro-power turbines, Brad Bowlin said the company will, nonetheless, partner with DEQ and Fish and Game to analyze weather data, incoming flows, oxygen levels and other factors to determine “if there’s something we need to do to our operations.”

Bowlin said Idaho Power hopes to discover what conditions were different during that four-hour period that could aid in forecasting to avoid future problems.

“That was the big issue, that this happened in such a short period of time,” Bowlin said.

Larry Larsen, owner of Snake River Fly Shop in Pocatello, said the Snake River below American Falls is blue-ribbon water utilized by countless anglers and key to his business’s success. In late July, he said the reach was fishing better than during any period in the past five years. But Larsen is also glad the damage wasn’t greater and is already hearing reports that the fishery is recovering.

“I had a customer come in who was fishing there this morning, and he was catching fish,” Larsen said.

AMERICAN FALLS — The Snake River’s banks were littered with several species of dead trophy fish when David Raisch floated the reach below American Falls Dam throughout Saturday.

“I observed multiple sturgeon that were just gasping for air, including some that were 5 feet long,” said Raisch, who works as a fly fishing guide with Palisades Creek Lodge.

Sources with the Idaho Department of Fish and Game say hundreds of trout, small-mouth bass and yellow perch and at least 10 sturgeon were victims of a fish-kill spanning from the dam to the Vista boat ramp and Pipeline area. It was apparently triggered when dissolved oxygen levels plummeted from late Thursday to early Friday.

Fish and Game officials anticipate delayed mortality may continue throughout the next few days.

The cause of the oxygen drop remains under investigation, but sources with the Idaho Department of Environmental Quality have a theory, which is supported by Fish and Game biologists. Lynn Van Every, DEQ’s regional water quality manager, said a prolonged period of hot and calm weather likely resulted in a layer of warm water trapping colder water devoid of dissolved oxygen. Strong winds within the reservoir likely blew the warm water layer upstream from the dam, allowing only the cold water to enter the dam’s penstocks — large pipes that feed Idaho Power turbines.

The cold-water surge lowered oxygen levels below the dam to the point that fish began to die. Van Every confirmed Idaho Power met the conditions of its permits to operate the dam and won’t be fined.

“It happened in relatively short order,” Van Every said. “It’s not uncommon to have low dissolved oxygen coming through, but it sort of happened in a hurry.”

Raisch fished the same reach on Friday night. Though he considered it odd that he had no bites, he didn’t notice the fish-kill until the following morning. He contacted Fish and Game to report the fish-kill after his Saturday float, also describing how surviving trout and smallmouth bass acted “as if they’d had a stroke.”

“It’s a heart-breaker,” Raisch said. “It takes a long time to build those good resources and trophy fishing.”

Dave Teuscher, regional fisheries manager with Idaho Fish and Game, said sensors within the dam and 150 yards downstream constantly monitor dissolved oxygen content, which is considered healthy for fish at levels of above 5 milligrams per liter. Teuscher explained the sensors detected levels dropping from 5 milligrams per liter to zero from 10 p.m. Thursday to midnight Friday. The sensors automatically triggered a blower to activate and oxygenate water flowing from the first penstock. A second blower activated when dissolved oxygen levels hadn’t sufficiently recovered a few minutes later. Ultimately, an alarm signaled Idaho Power staff to respond and open a spillway to add more oxygen.

“Everything Idaho Power has in their water-quality requirements occurred, and that was helpful because this thing could have really turned into a larger fish-kill if that hadn’t happened,” Teuscher said.

DEQ responded to the scene on Sunday, and a Fish and Game crew conducted analysis on Monday morning. On Tuesday afternoon, Fish and Game staff manned a boat, scouring for dead sturgeon to gather biological data, such as growth rate and age.

Some of the sturgeon that were killed were in excess of 30 years old, Teuscher said. The department started stocking them in the reach in the 1980s for catch-and-release fishing and has been stocking the river upstream from American Falls to Idaho Falls more recently.

Idaho’s sturgeon are considered a species of greatest conservation need.

Though Idaho Power was in compliance with its license and obligations to operate the hydro-power turbines, Brad Bowlin said the company will, nonetheless, partner with DEQ and Fish and Game to analyze weather data, incoming flows, oxygen levels and other factors to determine “if there’s something we need to do to our operations.”

Bowlin said Idaho Power hopes to discover what conditions were different during that four-hour period that could aid in forecasting to avoid future problems.

“That was the big issue, that this happened in such a short period of time,” Bowlin said.

Larry Larsen, owner of Snake River Fly Shop in Pocatello, said the Snake River below American Falls is blue-ribbon water utilized by countless anglers and key to his business’s success. In late July, he said the reach was fishing better than during any period in the past five years. But Larsen is also glad the damage wasn’t greater and is already hearing reports that the fishery is recovering.

“I had a customer come in who was fishing there this morning, and he was catching fish,” Larsen said.