Built in 1930 to capture water for a military installation at the mouth of a Wasatch Front canyon, Red Butte Reservoir has been harnessed for a new purpose, the rescue of Utah’s disappearing native fish.
“In the early 90s, they were introduced into this reservoir as kind of an insurance policy refuge population,” said one such biologist, Dale Fonken, while measuring suckers pulled from Red Butte last week. He and his colleagues recorded each fish’s weight, length and gender, and then injected an electronic identification tag into its underbelly.
Over the course of two weeks of netting, Fonken’s team with the Utah Division of Wildlife Resources captured 650 suckers for release in Utah’s largest freshwater lake which once was home to millions before human activities completely disrupted its natural processes. The fish’s native range is confined to Utah Lake and its tributaries, but this habitat as been devastated by historic dredging, pollution, water diversions and the introduction of invasive sport fish that dine on young suckers.
Chris Keleher, who heads DWR’s endangered species program, has spent most of his career on June sucker recovery. He recalled the time in the 1980s when his team estimated the total population at just 300 individuals.
“At the time we didn’t know how to raise them in a hatchery,” Keleher said. “Those that were left were 40 years old. That fish was as close to extinction as you could get.”
Utah fisheries biologists quickly learned how to harvest and fertilize sucker eggs and soon established the brood population credited with saving the species.
/cloudfront-us-east-1.images.arcpublishing.com/sltrib/DJVBLCZENZFDXHX4HLSJWBO5CM.jpg)
DWR tapped that brood to stock June suckers at Red Butte, where biologists have spent years studying their behavior. Considered a trash fish, the June sucker’s decline wasn’t taken seriously until it was almost too late.
“Before they got in trouble, nobody looked at them,” Keleher said. “Red Butte was the first place where we could document reproduction.”
After decades of stocking hatchery-reared fish at Utah Lake, sucker numbers have rebounded, but the species' survival remains at risk because an important element of sucker habitat is still missing.
The historic dredging and diking of Utah Lake’s tributaries was great for reclaiming land for agriculture, but it has been murder on larval suckers that are hatched upstream. The resulting swift currents push the fry into the lake before they are old enough to survive on their own, according to biologist Keith Lawrence, DWR’s native aquatics project leader.
“We know fish spawn in large numbers and we know there’s a lot of larvae that drift from off the redds [spawning habitat] out into the lake, but it doesn’t look like there’s much in the way of natural recruitment,” Lawrence said, referring to a species' ability to sustain itself. “I wouldn’t say there isn’t any, but it’s probably insufficient because of loss of habitat that used to be there around the margins of the lake.”
/cloudfront-us-east-1.images.arcpublishing.com/sltrib/R4Y5TPAMJVHJBI2RVV6KCIILTA.jpeg)
But a fix is in the works at a cost of tens of millions of dollars. Federal authorities have begun work forging 300 acres of critical habitat where the Provo River meets Utah Lake. The Provo Delta Restoration project will remove dikes and construct a system of channels and ponds that will serve as a safe haven for larval suckers. By spreading the river’s flow around a recreated delta, the young fish will be given the chance to grow for two years and reach a size of at least eight inches. That way they can swim in the lake water without becoming an easy lunch for the introduced walleye and bass that have replaced the its native fish.
“The intention for doing that is to create enough natural nursery habitat,” Lawrence said. “The restoration project will help create a self-sustaining population eventually and these sorts of stocking efforts will be less necessary.”
A partnership of several state and federal agencies spend $1.3 million a year on the sucker’s recovery, in addition to the millions the state has spent removing invasive Asian carp, whose presence has degraded the natural habitat and displaced native fish.
Keleher and Lawrence hope the delta restoration will put the fish on a path to long-term survival without assistance.
The insertion of microchips into the stocked fish helps gauge the success of these recovery efforts. Known as passive integrated transponders, or PIT tags, these chips contain information about the fish that can be read remotely as they roam Utah Lake.
In a procedure he has administered hundreds of times before, Fonken uses an injector to place the chips into the abdomens of the fish caught at Red Butte.
“Most of the fish is pretty armored. There’s a soft spot right there near the pelvic fins where we can insert that tag,” he said as he jabbed the device into one sucker’s belly. “They have a really good recovery rate with that. It’s a pretty noninvasive procedure.”
Antennae installed on the Provo, Hobble Creek and Spanish Fork rivers records the tagged fish as they swim out of the lake, providing biologists a picture of how well the stocked fish are surviving and whether they are attempting to spawn.
This year, 3,219 tagged fish entered these tributaries to spawn, mostly the Provo, according to Keleher. Those numbers are promising and going in the right direction. A large portion of those spawning fish came from Red Butte Reservoir, whose population reached 9,000 several years ago, according to Fonken.
“I think we’re starting to make a dent in the population, which is fine because they are naturally sustaining population,” he said. “We are talking about maybe transitioning this to an every-other-year type of deal. We could let the population recover and then continue to transfer them to Utah Lake. There is no shortage of suckers in here.”
The Red Butte suckers augment the 20,000 suckers that are transferred into Utah Lake every year from the state’s Fisheries Experimental Station in Logan, according to the DWR biologists.
The fish Fonken’s crew captured spend a night in a cage in Red Butte Reservoir then are transported by a tanker truck in the morning to Utah Lake State Park where they are released at the boat launch.
“We’ll probably get more mileage out of these 500 fish [from Red Butte on average each year] than the 20,000 hatchery fish,” Fonken said. “They’re conditioned to a natural environment. They’re conditioned to feeding on their own. They’re conditioned to avoiding predators. Here there’s Bonneville cutthroat trout, which is historically the natural predator of June sucker.”
Native cutthroat is the only other fish in Red Butte.
“It’s an artificial lake, but kind of a cool native ecosystem,” Fonken said.
"behind" - Google News
September 26, 2020 at 08:02PM
https://ift.tt/2G58tRv
A little reservoir behind the University of Utah is helping save an endangered fish - Salt Lake Tribune
"behind" - Google News
https://ift.tt/2YqUhZP
https://ift.tt/2yko4c8
Bagikan Berita Ini
0 Response to "A little reservoir behind the University of Utah is helping save an endangered fish - Salt Lake Tribune"
Post a Comment