For Endangered Salmon in California, a Very Measured Sip of Cold Water

With Chinook salmon facing lethally high stream temperatures, scientists deploy a new device to help manage the dwindling supply of cold water that the fish need to survive.

By Rich Press, NOAA Fisheries Science Writer | Follow Rich on Twitter: @Rich_NOAAFish
from The Fishing Wire

Chinook Salmon. Credit: Michael Humling/USFWS.

The State of California, now in the fourth year of a historic drought, is parched. But in the north of the state, at the bottom of the reservoir behind Shasta Dam, lies a big drink of cold water. For salmon in the Sacramento River, especially winter-run Chinook—considered by NOAA Fisheries to be among the eight endangered species most at risk of extinction—that cold water is a lifeline. Water managers tap it to cool off the river in summertime, when streams become hot enough to kill developing salmon eggs and newly hatched fry.

The cold water flows in from the mountains as snowmelt. But with winter snowpack at record lows, the supply of cold water is dwindling. If it’s not managed carefully, winter-run Chinook might be lost forever.

So last month, scientists from NOAA Fisheries and the University of Nevada, Reno, installed a new system to measure the temperature of the water behind Shasta Dam. The temperature profiler, which is based on fiber optic technology, will allow scientists to accurately estimate how much cold water is available so it can be used as efficiently as possible.

“The big question we’re facing, especially during this drought, is how much of the river can we keep cool enough for salmon eggs to survive?” said Eric Danner, the NOAA Fisheries biologist and salmon expert who is leading the project. “And can we keep it cool through October without running out of cold water first?”

Measuring the Vertical Temperature Profile

Cherisa Friedlander and Skip Bertolino of NOAA Fisheries and Scott Tyler of the University of Nevada, Reno, lower a fiber optic cable to the bottom of the reservoir behind Shasta Dam. The fiber optic system will provide a continuous, real-time temperature reading at every depth of the reservoir, allowing for more efficient management of the dwindling supply of cold water that endangered salmon need to survive. Credit: Rachel Hallnan/University of Nevada, Reno.
Cold water is heavier than warm water, so when it flows into the reservoir, it sinks to the bottom like hidden treasure. The agency that operates the dam, the U.S. Bureau of Reclamation, manages downstream water temperatures by mixing cold water from the bottom of the reservoir with warm water from above before sending it through the dam.

Until now, technicians from the Bureau of Reclamation measured the cold-water pool manually by going out on the lake every 2 weeks and dropping a temperature probe at various locations. That method is time-tested, but it left a lot of uncertainty in the results.

At the heart of the new system is a fiber optic cable that runs from the surface of the reservoir to the bottom. Photons are shot through the cable, and the backscatter can be interpreted to measure the temperature at every point along the cable. This will provide a continuous, real-time temperature reading at every depth.

The temperature data will be freely available online. In addition, water managers will be able to run computer simulations to predict how long the cold water will last, and what stream temperatures will result, given different scenarios of weather and dam operations.

Surviving in a New Environment

Scientists from NOAA Fisheries and the University of Nevada, Reno, install a fiber optic-based temperature sensor in the reservoir behind Shasta Dam. Credit: Rachel Hallnan/University of Nevada, Reno.
Before Shasta Dam was built, Chinook salmon traveled far upstream to spawn. Today, the dam blocks their passage, forcing them to spawn downstream, where water temperatures are higher. Because they didn’t evolve under these conditions, Chinook and many other species are not adapted to the hot water they find themselves in today.

Winter-run Chinook are especially vulnerable because of their timing. As their name indicates, they swim upstream in winter. Most spawn in late spring, and their eggs and newly hatched fry—the life stages most at risk from high temperatures—must survive the heat of summer.

“If the water gets too warm, the eggs are stuck in a tomb under the gravel,” said NOAA Fisheries biologist Garwin Yip. If high temperatures don’t kill the eggs outright, they can cause higher rates of disease. And even if the young fry do make it out of their nests, they face long odds as well, as high temperatures make predators more voracious.

The goal of water managers is to keep the average daily stream temperature no higher than 56 degrees Fahrenheit through October. Last year, due to imperfect estimates of its volume, the cold-water pool was unexpectedly drained by mid-September, and stream temperatures soon shot up to 62 degrees. Scientists estimate that only 5 percent of winter-run Chinook eggs survived as fry in the upper Sacramento River, compared to 25 percent survival in an average year.

Chinook salmon. Credit: NOAA.

“We don’t want a repeat of what happened last year,” Danner said.

Hopefully, with the new fiber optic temperature profiler in place, water managers will be able to take very controlled sips from the cold-water pool, and make sure it lasts until the salmon are out of danger.

Conservation Genetics Steers Gila Trout Management
Craig Springer
from The Fishing Wire

A trout that once stared at extinction offers wilderness angling opportunities

The trout stole its color from a southern New Mexico summer sunset. Gila trout sport a painter’s pallet of pink and olive, rose, yellow and copper and a few tones in between. Beneath the black pepper flakes that fleck its side lies a lexis—a language carried forward from another time. It’s an ancient language coded in molecules of proteins written by the press of time and experience in a land turned arid.

Gila trout, native only to headwater streams that vein over the Mogollon Rim of New Mexico and Arizona, have expressed in their genetic makeup a mapping of how to survive in the vestiges of what surely was a large and contiguous range. Their genetics equip them to face what nature may hurl at them in an already harsh environment.

It’s those innate characteristics coiled in the double-helix of DNA that U.S. Fish and Wildlife Service biologists strive to preserve in the fish. Conservation genetics is at its heart an investment in the future with an eye on the past. Dr. Wade Wilson with the Southwestern Native Aquatic Resources and Recovery Center in Dexter, New Mexico, knows Gila trout like few others can; he’s a geneticist and can de-code the language. It’s his charge in the conservation of Gila trout to help ensure that the diversity of genetic characters unique in this fish stay in the fish going forward.

Wilson works adjunct with another U.S. Fish and Wildlife Service facility in New Mexico, the Mora National Fish Hatchery near Las Vegas where captive stocks of the rare yellow trout are held. Hatchery biologists are fully immersed in Gila trout captive breeding, and it’s done smartly, carefully, through the consult of Wilson.

“We monitor genetic diversity in captive trout to ensure that what we have in the hatchery represents what we have in the wild,” said Wilson. That mixture is essential for the future. “The more genetic diversity that exists among the fish, the better chance those future generations of Gila trout can adapt to changing environments and stressors and diseases in wild populations,” Wilson adds.

“Here’s how we get it done,” explains an enthusiastic Nate Wiese, Mora’s manager and lead fisheries scientist. “Each fish gets a microchip injected just under the skin just like your vet can do for your dog. That chip gives each fish a personal ID, like a social security number. Knowing each fish at an individual level is a first step in securing the future of Gila trout.”

With every captive fish in the hatchery marked as such, biologists take non-lethal tissue samples from the fish, a tiny piece of fin. From there it’s up to Wilson and his staff using leading-edge technology to look deep at each fish—at the molecular level. Wilson will pinpoint individual fishes with the rarest of genetics in the captive populations and suggest what Wiese calls “pair-wise spawns.” It’s akin to arranged marriages but with the express scientific purpose to ensure that the rarest of genetic characters found by Wilson are carried forward in the next generation of fishes. Males and females that differ among various genes make the best partners.

The Gila trout was described by science a mere 65 years ago. Through much of that intervening time—50 years—it had been closed by law to angling as the fish stared at extinction. Its lot improved with conservation and was down-listed from “endangered” to “threatened” in 2006, and opened to fishing a year later. And so it remains, threatened and fishable, despite a welter of catastrophic wild fires—the sort that makes the evening network news broadcast for days on end.

“An integral part of the conservation strategy calls to replicate in the wild the distinct genetic lineages,” said Wiese. It’s a measure of conservation security to give a geographic spread between populations. “But what happens when a massive fire threatens to gobble up the original and replicate populations? The hatchery is the back up.”

Fire is hard on trout, particularly when a mountain stream turns into a slug of ash slurry at first rain post-fire. The Whitewater-Baldy Fire that decimated the Gila Wilderness in 2012 necessitated a trout rescue ahead of such circumstances. New Mexico Fish and Wildlife Conservation Office biologist Dustin Myers based in Albuquerque led such rescues involving pack horses and helicopters and hatchery trucks from streams sure to be slugged by ash. Now, Mora National Fish Hatchery is home to the only known population of the Spruce Creek lineage of Gila trout. Three other strains are held there, too: Main Diamond Creek, Whiskey Creek and South Diamond Creek lineages.

Aside from the robust genetics plans that steer captive breeding, Wiese manages the hatchery to produce Gila trout conditioned toward a wild environment. Instead of growing lazy trout as fat as toads, they are in a captive environment that mimics nature—like boulders, plants and fast-flowing water. “We get them off the couch and on a treadmill,” said Wiese. “They are going to be better suited for real streams. It’s like tough-love for your children.”

Those real streams are still healing from the 2012 fire and the Silver Fire that scorched headwaters atop the Black Range in 2013, and fish will return to them this autumn. Myers makes that call as to what streams are ready for trout. “Since the Whitewater-Baldy Fire we’ve replicated Whiskey Creek lineage in McKenna Creek and Upper White Creek,” said Myers. “Whiskey fish will also go into Sacaton Creek this year. But Whiskey Creek itself is still healing and we have to wait for habitat conditions to improve.”

It’s about the habitat—including ensuring that Gila trout waters remain free of mongrel or nonnative trouts that compromise the genetic integrity of pure lineages via interbreeding. Barriers, made on site, or natural waterfalls are a means of segregating fishes. Toward that end, Myers recently worked with the Forest Service to restore a vital barrier, a natural waterfall, by blasting out lodged boulders to ensure 21 miles of prime Gila trout habitat in the West Fork Gila remain free of unwanted fishes.

The lack of habitat has been a vexation in Gila trout conservation. But science married with the resolve of individuals who care about this beautiful bright trout is a way forward. A certain splendor in the spectra of inspiring pigments reflected by a wet Gila trout call to mind Emerson: “If eyes were made for seeing, then beauty is its own excuse for being.” But the beauty is richer than what strikes the eye; it’s that Gila trout sheltered in a hatchery and those facing the rigors of the wild still carry today the impress of the past.

Craig Springer works for the U.S. Fish and Wildlife Service in Albuquerque, New Mexico. Learn more at www.fws.gov/southwest

Editor’s Note:

The Southwest Region recently introduced Emphasis Areas as a way to focus our limited resources on geographic areas with the highest conservation need and potential for success, which also have opportunities for leveraging funding. The Mogollon Rim, home to Gila trout, is one of five geographic areas determined by the Regional leadership team to be an Emphasis Area.

‘State of the Trout’ report details threats to America’s coldwater fisheries
from The Fishing Wire

The nation’s native trout are in peril, but report shows path to recovery, long-term survival

WASHINGTON — America’s native trout have declined dramatically over the last century thanks to a number of threats ranging from hatchery fish stocking to logging and mining to poorly designed roads and livestock grazing practices. Now a new suite of threats, from energy development to a changing climate, poses even greater challenges.

According to a new Trout Unlimited report titled, “State of the Trout,” these threats are greater than ever, and they make for an uncertain future for coldwater fish if steps are not taken to protect and restore habitat, reconnect tributaries to mainstem rivers and keep native trout populations viable for the benefit of anglers and the country’s riparian ecosystems.

The report notes that, of the nation’s 28 unique species and subspecies of trout and char, three are already extinct. Of the remaining 25 species, 13 occupy less than 25 percent of their native ranges. Trout across America are dealing with the cumulative effects of resource extraction, climate change and the introduction and persistence of non-native fish into native trout waters. But, according to the report, there is hope for trout and for those who fish for them all across the nation. The report lays out a roadmap for native trout recovery and persistence, but it will require a host of advocates playing vital protection and restoration roles for years to come.

“It’s daunting when you consider the scope of the threats facing coldwater fish in the United States,” said Chris Wood, TU’s president and CEO. “But if you step back and look at the work that TU and our partners are already doing all across the country, it’s encouraging to see progress and to know that, with help from volunteers, private industry, government agencies and elected officials, we can replicate that progress and keep trout in our waters.

“And that’s why this report isn’t just for anglers or for biologists,” Wood continued. “This is a report for all Americans, because trout require the cleanest and coldest water to survive—and we all need clean water.”

Like Wood, report author Jack Williams, TU’s senior scientist, believes all Americans have a stake in this report, and that it will require a collective effort to ensure a future for native trout in America.

“The reasons many populations of native trout are on the ropes is because of our growing human population and the increasing demand on water resources,” Williams said. “For eons, the great diversity of trout genetics and life histories coupled with their widespread distribution allowed them to thrive. The changes we’ve made to their habitat over time, just by pursuing our lifestyle, has had a huge impact on water quality, connectivity and trout habitat. We’ve also stocked non-native trout on top of native populations, to the point where even well-adapted native trout are overcome by repeated stockings.”

Williams notes that common-sense conservation measures in the years to come can help native trout recover. But, restoration needs to take place across entire watersheds and be sustained over decades.

For instance, in Maggie Creek in northwest Nevada, collaborative restoration has been underway since the late 1980s. TU’s work with ranchers, the Bureau of Land Management and mining companies have restored 2,000 acres of riparian habitat and today native Lahontan cutthroat trout have been completely restored in 23 miles of Maggie Creek and its tributaries. In Maine, where TU and its partners helped negotiate the removal of two dams and construction of fish passage on a third, more than 1,000 miles of the Penobscot River has been reopened to Atlantic salmon, striped bass, herring and shad. In the West, in states like Idaho and Colorado, sportsmen and women have mobilized and helped protect millions of acres of intact, functional habitat that is vital to trout and the waters in which they swim. Broad-scale restoration work on streams in the Driftless Area of the Midwest has translated into waters that once held only 200 fish per mile to holding 2,000 fish per mile.

TU’s public and private partners are key to the report’s findings. Without help from government, private entities and volunteers, trout truly do face an uncertain future.

“The health of America’s trout is directly connected to the health of our nation’s watersheds—watersheds that provide clean drinking water, drive economic growth and support recreational fishing opportunities for millions of people across the nation,” said U.S. Fish and Wildlife Service Director Dan Ashe. “The ‘State of the Trout’ report provides a valuable overview of the health of these fisheries, helping Trout Unlimited, the Fish and Wildlife Service and our partners identify priority areas for conservation.”

Like Ashe, Neil Kornze, director of the U.S. Bureau of Land Management, believes in partnerships to ensure trout survive for coming generations to enjoy.

“Trout Unlimited’s new report details the many challenges facing our nation’s native trout, and offers some real, science-based solutions to ensure trout remain a part of the American landscape for generations to come,” Kornze said. “Their approach to protecting and restoring native trout populations supports the BLM’s fisheries programs and our landscape-scale approach to land management. The report is thoughtful and scientifically sound—it’s a valuable addition to ongoing efforts to restore our nation’s coldwater fisheries.”

U.S. Forest Service Chief Tom Tidwell also noted that partnerships are vital to the long-term persistence of native trout in America.

“The Forest Service is fortunate to be able to leverage hundreds of thousands of dollars, along with help from TU, hundreds of volunteers, local communities, schools, and citizens to restore healthy trout habitat,” Tidwell said. “The Forest Service will stay a close partner with TU in trout and aquatic habitat protection and restoration across the U.S.”

The report, according to Doug Austen, executive director of the American Fisheries Society, offers a glimpse at just how important trout are to America’s waters.

“Today’s report paints a troubling picture of the status of trout, but it also features the hope that the more than 9,000 members of AFS share: effective partnerships with scientists, government agencies, fisheries managers, conservation groups and landowners can achieve amazing recovery results for these imperiled fish,” Austen said.

And trout aren’t just a biological asset, either. Ben Bulis, the president and CEO of the American Fly Fishing Trade Association, notes that trout are vital to the industry his association represents.
“Trout are the foundation of the fly fishing world,” Bulis said. “Their health and the health of their habitat is vital to the bottom line of the growing fly fishing industry. This report not only lays out the challenges trout face, but it offers solutions and a common-sense approach to ensuring trout persist and thrive well into the future.”

In the end, Wood said, it’s really about hope and optimism.

“While the report’s findings are dire,” Wood said, “there are hundreds of examples where we’ve corrected past mistakes. Trout are incredibly adaptable and resilient—we just have to give them half a chance, and they’ll recover. That’s the message in this report—we can improve trout habitat, increase trout populations and make fishing better. But we need the support and the will to do it. Nobody is saying it will be easy.”

Read the report today at tu.org/stateofthetrout.

Rainbow Trout On The Comeback Throughout Colorado
from The Fishing Wire

Dave Parri of Hot Sulphur Springs, holds a rainbow trout he caught last winter on the upper Colorado River. The rainbow is a whirling disease resistant fish developed by Colorado Parks and Wildlife scientists. (Credit Colorado DPW)

DENVER, Colo. – After being devastated by whirling disease in the 1990s, rainbow trout populations are increasing in most major rivers in the state thanks to a 20-year effort by Colorado Parks and Wildlife aquatic scientists and biologists.

“It’s been a long road, but bringing back populations of fish that were essentially extirpated from Colorado can only be called a huge success,” said George Schisler, CPW’s aquatic research team leader who is based in Fort Collins.

The comeback is positive news for anglers who can once again fish for rainbows and brown trout in Colorado’s big rivers and streams. For the past 15 years brown trout have dominated most of the state’s rivers. But since last summer, anglers have reported that they are catching nice size rainbows in the upper Colorado, Rio Grande, upper Gunnison, Poudre, East, Taylor, Arkansas and Yampa rivers and others.

The whirling disease problem started in 1986 when a private hatchery unknowingly imported infected rainbow trout from Idaho that were stocked in 40 different waters in Colorado. The disease eventually spread throughout the state and even infected CPW hatcheries which caused more waters to be infected.

Whirling disease is caused by a spore that infects the spine of very young fish. The infection deforms the spine causing the fish to swim in a whirling pattern. They die shortly after becoming infected. When whirling disease hit Colorado’s rivers, natural reproduction of the species virtually ended. That allowed brown trout, which are not affected by the disease, to become the dominant sport fish.

By the mid 1990s rivers in Colorado and other western states were thoroughly infected.

These are hatchery raised fish, all the same age. The larger fish are the Hofer strain. (Credit Colorado DPW)

At a national conference on whirling disease in Denver in 2002, a German researcher presented information that showed trout at a hatchery in Germany, operated by a family named Hofer, were resistant to the parasite. Colorado’s aquatic staff moved quickly to import eggs from Germany which were hatched at the University of California at Davis. The fingerlings were then brought to CPW’s Bellvue hatchery near Fort Collins.

The fish grew quickly and their disease resistance was proven. By 2006 Schisler stocked some of the Hofers in two reservoirs west of Berthoud. Anglers reported that the fish hit hooks hard and were easy to catch. This made them ideal for stocking in reservoirs where anglers expect to catch fish.

But because the “Hofers” had been domesticated in a hatchery for generations, Schisler and his colleagues knew that the fish did not possess a “flight response” to danger. They would have little chance in creeks and rivers where they need to avoid predators and survive fluctuating water conditions. So CPW researchers started the meticulous process of cross-breeding the Hofers with existing strains of trout that possessed wild characteristics and had been stocked in rivers for years.

After three years some of the crosses were ready for stocking in rivers –- with the hope that the fish would survive, reproduce and revive a wild, self-sustaining population of rainbows. Biologists first stocked 5-inch Hofer-crosses, but they didn’t survive. Then in 2010, fingerlings were stocked in the Colorado River near Hot Sulphur Springs. When researchers returned to survey the area 14 months later they learned the experiment had finally paid off. They found good numbers of 15-inch rainbows and evidence that young fish were hatching in the wild.

CPW biologists have been stocking fingerling Hofer-crosses throughout the state at different sizes and times of year to optimize survival. The young fish are surviving and Schisler is confident that Colorado’s rivers and streams are again home to truly wild rainbows.

The Hofers are also providing other benefits to CPW and Colorado’s anglers. Because the
fish grow much faster than standard rainbow strains, state hatcheries can raise more fish in a shorter amount of time. They can also be crossed with CPW’s various trout strains and are well suited to reservoir where they don’t reproduce naturally but are ideal for still-water anglers.

In the late 1990s many CPW scientists worried that truly wild rainbow trout would disappear. Now a new chapter for sport fishing in Colorado is just getting started … again.

Wisconsin stocked Chinook salmon outperform Lake Michigan average, new research shows
from The Fishing Wire

Today’s feature comes to us from the Wisconsin DNR, which is justifiably proud of the success of its Chinook salmon stocking program on Lake Michigan.

Wisconsin stocked chinook salmon outperform Lake Michigan average, new research shows A cooperative research project by the U.S. Fish and Wildlife Service, DNR and agencies in other states used a mechanical process to insert tiny coded wire tags into the snouts of young lake trout and chinook. U.S. Fish and Wildlife Service Photo

MADISON — Chinook salmon stocked by the Wisconsin Department of Natural Resources survive very well and contribute substantially to the state’s strong Lake Michigan fishery, new research from the U.S. Fish and Wildlife Service and DNR shows.

As the lake’s top predator, it’s common for both stocked and wild chinook to travel hundreds of miles to feed as they mature and at any given time during the summer, state anglers may catch chinook stocked by Wisconsin, Michigan, Illinois or Indiana. However, the ongoing three-year cooperative research project shows Wisconsin stocked fish have an above average likelihood of surviving to harvest and are being caught in comparatively large numbers in an area stretching from Door to Kenosha counties.

At the same time, state anglers are benefiting from natural reproduction of wild fish from Michigan streams and tributaries to Lake Huron.

“Wisconsin offers a world class recreational fishery and DNR’s Lake Michigan stocking efforts continue to play a key role in sustaining this resource and its multimillion dollar economic impact,” said DNR Secretary Cathy Stepp. “This study reinforces the importance of our high quality hatchery efforts while supporting the value of ongoing investments in our fisheries operations.”

Dave Boyarski, DNR fisheries supervisor for northern Lake Michigan, said the department has been working closely with the Fish and Wildlife Service’s Fish Tag and Recovery Lab near Green Bay to tag chinook fingerlings as well as collect and analyze the tags from the heads of recovered fish. Chinook salmon tagging for the recent multistate project began in 2011 and the analysis involved some 46,000 recovered tags.

The coded wire tags resemble tiny pieces of pencil lead and are inserted through a mechanized process that has proven more efficient and less stressful to the fish than previously used hand-held methods. During 2014 alone, state fisheries managers in Wisconsin, Illinois, Indiana and Michigan tagged and released more than 2.9 million chinook salmon bound for the waters of lakes Michigan and Huron. Wisconsin DNR’s Wild Rose and Kettle Moraine Springs hatcheries contributed about 824,000 of that total.

Illustrating the excellent returns of fish stocked by Wisconsin’s hatcheries, from 2011 to 2013 Wisconsin provided 38 percent of all the chinooks that were stocked in Lake Michigan. Yet from 2012 to 2014, Wisconsin stocked fish accounted for some 49 percent of stocked fish harvested throughout the lake and 57 percent of the stocked fish taken in Wisconsin waters.

The results of the analysis show the fish stocked by Wisconsin DNR appear to survive at better than average rates and account for a relatively large percentage of the stocked chinook salmon harvested throughout Lake Michigan, Boyarski said. In addition, anglers are benefiting from strong reproduction among wild chinook, which accounted for about 60 percent of the total harvest throughout Lake Michigan in 2014.

Brad Eggold, DNR fisheries supervisor for southern Lake Michigan, said the study demonstrates the benefits of Wisconsin’s investment in the Wild Rose Fish Hatchery where the majority of Wisconsin Chinook salmon are reared. The results also reinforce the importance of multistate cooperation and the involvement of anglers throughout the region.

“We greatly appreciate the opportunity to work with the U.S. Fish and Wildlife team to collect this data, which will inform our management efforts going forward,” Eggold said. “We also want to thank the many thousands of anglers and other partners who aided this effort by collecting the tens of thousands of fish heads needed for the analysis.”

Charles Bronte, senior fisheries biologist with the U.S. Fish and Wildlife Service, said the multistate effort was initiated in an attempt to understand the growth and survival of chinook, their movement throughout the connected waters of lakes Michigan and Huron and levels of natural reproduction. These measures are critical to the DNR for managing chinook in response to a changing base of forage fish.

“If we’re going to find the answers, we need this kind of coordinated research among all the states in the region that stock chinook because the fish don’t stay in one place,” Bronte said. “What we learn from this work will help guide best practices for producing healthy fish throughout the region, maximize returns and provide further insight into the conditions essential for these fish to thrive.”

Other important insights gleaned from the work include the fact that natural reproduction now accounts for some 60 percent of the chinook population from the combined year classes 2011, 2012 and 2013. However, lower lake levels and stream flows during 2012 and the subsequent harsh winter contributed to a reduction in successful natural spawning and survival for the 2013 year class of chinook, which was only 37 percent wild fish.

The team of experts said more work and more time will be needed to assess whether natural reproduction will rebound following the difficult 2013 cycle. Disruptions in the lake’s food web caused by invasive mussels and other species also bear further monitoring and will influence future management decisions.

“The study reinforces the importance of science-based management efforts and provides a wealth of information that we intend to share with our stakeholders,” Boyarski said. “In the months ahead, we’ll use what we are learning to examine our own management practices and implement strategies that increase the return on our stocking and management efforts going forward.”

To learn more about the research and the Lake Michigan fishery, search the DNR website dnr.wi.gov and search “Fishing Lake Michigan and “chinook salmon research.”

FOR MORE INFORMATION CONTACT: Dave Boyarski, DNR northern Lake Michigan fisheries supervisor, 920-746-2865; David.Boyarski@Wisconsin.gov; Brad Eggold, DNR southern Lake Michigan fisheries supervisor, 414-382-7921, Bradley.Eggold@wisconsin.gov; Charles Bronte, U.S. Fish and Wildlife Service senior fisheries biologist, 920-412-8079, Charles_Bronte@fws.gov; Jennifer Sereno, DNR communications, 608-770-8084, Jennifer.Sereno@wisconsin.gov

Once nearly extinct, endangered Idaho sockeye regaining fitness advantage

Contributed by Michael Milstein, Northwest Fisheries Science Center, NOAA
from The Fishing Wire

Endangered Snake River sockeye salmon are regaining the fitness of their wild ancestors, with naturally spawned juvenile sockeye migrating to the ocean and returning as adults at a much higher rate than others released from hatcheries, according to a newly published analysis. The analysis indicates that the program to save the species has succeeded and is now increasingly shifting to rebuilding populations in the wild. Biologists believe the increased return rate of sockeye spawned naturally by hatchery-produced parents is high enough for the species to eventually sustain itself in the wild again.

“This is a real American endangered species success story,” said Will Stelle, Administrator of NOAA Fisheries’ West Coast Region. “With only a handful of remaining fish, biologists brought the best genetic science to bear and the region lent its lasting support. Now there is real potential that this species will be self-sustaining again. The sockeye didn’t give up hope and neither did we.”

Biologists Paul Kline of the Idaho Department of Fish and Game and Thomas Flagg of NOAA Fisheries’ Northwest Fisheries Science Center report the promising results in the November issue of Fisheries, the magazine of the American Fisheries Society.

These findings demonstrate that the program to save Snake River sockeye can indeed reverse the so-called “extinction vortex,” where too few individuals remain for the species to sustain itself. Some thought that Snake River sockeye had entered that vortex in the 1990s, highlighted in 1992 when the sole returning male Redfish Lake sockeye, known as “Lonesome Larry” captured national attention.

NOAA Fisheries earlier this year released a proposed recovery plan for Snake River sockeye, which calls for an average of 1,000 naturally spawned sockeye returning to Redfish Lake each year, with similar targets for other lakes in Idaho’s Sawtooth Valley. About 460 naturally spawned sockeye returned to Redfish Lake this year – the most since the program began – out of an overall record return of about 1,600.

The article in Fisheries recounts the 20-year history of the scientific program to save the Snake River sockeye. The program began with 16 remaining adult sockeye – 11 males and five females – taken into captivity from 1991 to 1998. Through advanced aquaculture techniques, the program has retained about 95 percent of the species’ remaining genetic variability, while boosting surviving offspring about 2,000 percent beyond what could be expected in the wild.

Without such advances, the scientists write, “extinction would have been all but certain.”

The program funded by the Bonneville Power Administration has released more than 3.8 million sockeye eggs and fish into lakes and streams in the Sawtooth Valley, and tracks the fish that return from the ocean. Hatchery fish returning as adults have also begun spawning again in Redfish Lake, increasingly producing naturally spawned offspring that are now also returning.

A new analysis of those returns shows that the naturally spawned sockeye are returning at rates up to three times higher than those released from hatcheries as smolts, and more than 10 times greater than those released as even younger pre-smolts.

The higher returns indicate the naturally spawned fish are regaining the fitness the species needs to better survive their 900-mile migration to the ocean, their years at sea, and the return trip to Redfish Lake. A salmon population must produce at least one returning offspring per adult to sustain itself. Naturally spawned sockeye have returned at more than twice that rate in some recent years, indicating that under the right conditions they can not only sustain the species but add to it.

The results also suggest that hatchery-produced sockeye may regain the fitness advantages they need to sustain their species in the wild much faster than had been previously estimated, the scientists reported. Biologists caution that the current results span only three years so far, but indicate that fitness – and, in turn, survival – can improve in as little as only one generation in the wild. “We hoped we could get returns equivalent to what you’d expect to see from a hatchery,” said Flagg, manager of the NOAA Fisheries Northwest Fisheries’ Science Center’s Manchester Research Station. “We’ve seen the population respond even better than that, which bodes well for the idea that the lakes can produce the juveniles you’d want to see to get to recovery.”

More information on Northwest Fisheries Science Center/Salmon captive broodstock programs is available at: http://www.nwfsc.noaa.gov/research/divisions/efs/hatchery/salmon_captive/index.cfm