News & Stories

  • The Salmon that Were Born to Survive/Most salmon die after their first spawning. But not all do. Scientists call the survivors “kelts

    March 28, 2019

    Hakai Magazine by Chris Baraniuk

    Everyone makes the same remark: it’s just like counting tree rings. When you press a salmon scale between two small panes of glass and peer at it through a microscope, that’s akin to what you see: an array of concentric circles from the center of the scale out to the edge. As with trees, these rings tell a story.

    Recently, Chris Conroy, a fisheries manager in Scotland, took scales off a salmon he’d sampled in a river and inspected them in a lab. Multiple rings form every year in salmon scales. In times of slow growth, such as the winter when salmon eat less, the rings form closer together, in tight, dark bands. At a few key locations on the scale, Conroy noticed several of these dark bands but two wavy ones stood out. These documented years when this fish had returned from the sea, making the arduous journey upriver to spawn. The rings showed that this fish had been captured on its third spawning run.

    “That’s six migrations to and from the sea—amazing,” the fishery wrote in a tweet.

    Salmon that have spawned before are called kelts. And some kelts, like the Scottish individual, go on to spawn several more times. The technical term for this behavior is iteroparity, but the fish are usually referred to as repeat spawners. Repeat spawners that have spawned three or more times are rare, and although not all species of salmon can be repeat spawners, Atlantic salmon, like the one found by Conroy, can.

    For the vast majority of salmon, the trip upriver to spawn is a suicide mission. The fish expend nearly every ounce of energy they have fighting currents, leaping up waterfalls, and dodging predators. Their bodies change—they absorb parts of their skeleton and parts of their skull, using the calcium to fuel the trip. Males grow a hook on their lower lip. In most cases, after they’ve laid and fertilized their eggs, the salmon die.

    For Atlantic salmon, the whole journey can cover more than 2,500 kilometers, and is a brutal assault on the salmon’s system. Each run involves serious obstacles, with anthropogenic threats like power station turbines, which can mash a salmon to pieces, being a more recent addition, says Eva Thorstad, a fish ecologist at the Norwegian Institute for Nature Research in Trondheim.

    Yet somehow, many fish survive. The kelts that make this trip multiple times can live for more than a decade. Incredibly, they always return to the same river where they themselves hatched. It doesn’t matter if you pick them up and move them to a different location, they will still eventually come back to their river, says Thorstad.

    These are salmon that were born to survive. Still, we don’t know all their secrets. As scientists put it in one recent paper[PDF], while Atlantic salmon in general are well studied, “comparatively little is known about the survival and movements of kelts.” For instance, the highest possible number of repeat spawning is unclear, though the present record is seven.

    In most parts of the world, the fact that some salmon can be repeat spawners in this way is not very well known. But in the north of Norway, local communities have long understood that kelts are different, says Elina Halttunen, a salmon specialist at Norway’s University of Tromsø.

    Halttunen wrote her doctoral thesis on repeat spawners in Norway’s Alta River, well inside the Arctic Circle. In this area, it’s not uncommon to find salmon that have returned for a fourth spawning. Locals know how to recognize kelts—they are the unusually large but tatty fish that are often seen in the rivers in early spring.

    Having used so much energy to swim upriver, the fish are hungry, and easily caught on a lure.

    “That’s how we could do the study—we could catch them by fishing,” explains Halttunen.

    She says that in times gone by when food was scarce, people would eagerly seek out kelts. Though the fish are lean, they are large, and locals would grind them up, mixing them with eggs, milk, and flour to make fishcakes that would then be fried—Støingkake, a Scandinavian delicacy.

    The surprising thing that Halttunen and her colleagues discovered about kelts was just how many of them there were in this part of Norway. And with each spawning, survival only becomes more impressive. In general, only 30 percent of Atlantic salmon survive to spawn again. Kelts have already beaten the odds once—with every subsequent journey upriver, they beat the odds again. And yet, female kelts punch above their weight in terms of their egg deposits.

    While about 20 percent of the female population in a river might consist of kelts, those fish have been found to contribute nearly 30 percent of all the eggs, on average. Among female fish, repeat spawners are far more fecund, in other words, they produce more offspring. They are bigger than first-timers, and more experienced. According to Halttunen, they are better at building nests, and have more—and potentially larger—eggs. Males also find the older kelts more attractive, so their eggs are more likely to be fertilized. According to Halttunen’s simulations, a small group of kelts could contribute as much as 60 percent of all eggs in one of the Alta’s tributaries. That might occur, she explains, at a time when far fewer first-time spawners arrive in the river.

    Repeat spawners are clearly capable of strongly influencing the next generation. “They are kind of an insurance policy of the population,” says Halttunen. “They are the buffer in bad times.”

    But semelparous salmon, which only spawn once and then die, are still the norm. So what makes a repeat spawner?

    Tutku Aykanat, a fish physiologist at the University of Helsinki in Finland, and his colleagues recently published a paper in which they describe a key genetic difference between semelparous and iteroparous salmon. They found that fish whose genomes had a characteristic section around a gene called vgII3 were more than twice as likely to become repeat spawners.

    The team discovered this by examining DNA from thousands of archived salmon scales. Aykanat says that the gene isn’t the only thing that determines iteroparity. There must be environmental factors, too, but exactly what they are remains unknown. And there’s another mystery. Repeat spawning has evolved in Atlantic salmon but not, for example, in Pacific salmon.

    Whatever makes the kelts tick, they are needed, says Glenn Crossin, a biologist at Dalhousie University in Halifax, Nova Scotia. He has studied Atlantic salmon in eastern Canada where the species is struggling. Years of acid rain has altered the rivers, causing fewer eggs to hatch into healthy fish. In regions with declining populations, kelts, especially the fecund females, could be extremely beneficial. “You really want these iteroparous individuals,” says Crossin.

    His own research has shown[PDF] that repeat spawners, despite their presumed hardiness, don’t do well if they’re interfered with. When hatcheries retrieve eggs from repeat spawners, the fish tend to die swiftly before they can spawn again. Because they are particularly vulnerable to this sort of intervention, Crossin says conservationists need to be able to distinguish them from other females—and leave the kelts alone.

    Perhaps by doing so, the Atlantic salmon in eastern Canada will have a better chance of recovering—all thanks to these wise old kelts.

    Read the article at the source »

  • North Coast salmon season expected to be most prosperous since 2014

    March 23, 2019

    Santa Rosa Press Democrat by Mary Callahan

    There’s some good news this spring for the Northern California fishing fleet, which is looking forward to more available salmon this season compared with recent years.

    Local fishermen and women hope to get out on the water earlier, as well, perhaps by May 1.

    “Guys are kind of excited, because it looks like we’re going to get more time on the water, so that’s a better chance at catching some fish,” said Lorne Edwards, a veteran fisherman of 30 seasons and president of the Fishermen’s Marketing Association of Bodega Bay.

    Restrictions remain inevitable, but the official forecast released last month suggests there are more spawning-age king salmon out in the ocean waiting to be caught than since 2014.

    The key is getting the trollers out when the fish are around and with enough time to find them if it’s not obvious where they are at first, Edwards said.

    Biologists from the California Department of Fish and Game have estimated nearly 380,000 adult salmon in the ocean from the Sacramento River fall run of chinook this year,

    The highest forecast in the previous three years was 299,600 in 2016, though the models used in the calculations are imperfect, particularly in recent years.


    The estimates nonetheless bode well for the salmon season, as they inform the decision- making that determines when sport and commercial fishing is allowed in various locations up and down the coast each year.

    The commercial schedule won’t be known for a couple of weeks. Final deliberations are scheduled for next month during a weeklong meeting of the Pacific Fishery Management Council in Rohnert Park, beginning April 9.

    As it does each year, the council will be choosing between three alternative schedules of varying lengths for the commercial fishery with starting dates for the management district that includes Bodega Bay of May 1, May 17 or June 11.

    Each schedule also includes most or all of June, July and August. The most liberal schedule, starting May 1, also includes all of September, while the schedule that includes half of May also takes in half of September. The shortest season would exclude both May and September.

    “We’re hoping for the best,” said veteran Bodega Bay fisherman Tony Anello, whose entire family is invested in the local fishery as the owners of two commercial vessels and proprietors of Spud Point Crab Co. “It looks better than it has been.”

    The Sonoma Coast district, known as the San Francisco cell, runs between Pescadero in San Mateo County and Point Arena on the southern Mendocino Coast.

    The sport season opening dates already have been announced. They are Saturday, April 6, from Pigeon Point, just north of Santa Cruz, south to Mexico, and Saturday, April 13, from Pigeon Point to Horse Mountain, just north of Eureka in Humboldt County.

    The commercial salmon season has long been a mainstay of the North Coast fishery, with king salmon running so plentifully in the region they were practically legendary.

    But environmental damage, development, logging and demand on streams and rivers where the juvenile anadromous fish spend their first year has taken a toll on salmon stocks over the decades, along, more recently, with changing ocean conditions and years of record drought.

    After chinook salmon stocks crashed a decade ago, resulting in complete closure of the fishery in 2008 and ’09, the fleet enjoyed a comeback in 2013, thanks to substantial rain in the winter of 2010-11 that allowed juvenile fish making the journey downstream to the ocean that year to survive, despite “being lousy swimmers” subject to predation or stranding if there is insufficient flow, said John McManus, president of the Golden Gate Salmon Association.

    That year the commercial fleet landed an impressive 3.8 million pounds of salmon statewide, including 639,000 pounds in Bodega Bay valued off the boat at $3.8 million, and 1.4 million pounds in Fort Bragg with an ex-vessel value of $7.7 million, according to California Fish and Wildlife data.

    That “was the last really good year,” McManus said.

    Last year’s total statewide catch was about 900,000 pounds valued at $8.39 million.

    The Sacramento River fall run of chinook, which supplies the bulk of the fish caught off San Francisco and the Sonoma Coast, technically remains in need of rebuilding because of three consecutive years in which too few fish returned upstream to spawn, missing mandated targets intended to ensure sustainability of the fishery. So even though greater abundance has been forecast that could allow more than the 73 days allowed in the local fishing district year, there will be some constraints to allow for increased spawner returns.

    Concerns about several other salmon stocks, including the Klamath River fall run chinook and federally protected Sacramento River winter chinook and California Coastal chinook, could prompt regulators to impose additional restrictions.

    But “we’re cautiously optimistic,” McManus said. “We got really good rain in the spring of 2017, and that greatly boosted survival of juvenile salmon as they were exiting the Central Valley at that time. These are the same fish that are now adults we could be catching this year.”

    A public hearing on the alternative season schedules will be held in Ukiah at 7 p.m. Tuesday at the Hampton Inn Grand Ballroom, 1160 Airport Park Blvd. Further information is available at pcouncil.org.

    Read the article at the source »

  • Will salmon and steelhead once again spawn on the Mokelumne above Pardee?/

    March 19, 2019

    Red, Green and Blue By Dan Bacher

    The California Department of Fish and Wildlife reported a modern record of more than 19,900 fall-run Chinook salmon returned to spawn in the lower Mokelumne in the fall of 2017. The 2018 fall salmon returns were also impressive, with a total return of 17,474 fish.

    These record runs have contributed greatly to the ocean recreational and commercial fishery over the past couple of years. The Mokelumne, a relatively small river, provided 33 percent of the Central Valley fall Chinooks caught in the recreational fishery and 43 percent of the commercial fishery in 2018, according to the Pacific Fishery Management Council (PFMC).

     

    “The advances in releases of salmon, coupled with the Mokelumne River Fish Hatchery Manager Bill Smith’s care of the fish, have resulted in big, strong fish that are in really good shape,” said John McManus, President of the Golden Gate Salmon Association. “The Mokelumne Hatchery has apparently discovered some type of magic in their stewardship of salmon.”

    If a pilot study bears fruit, salmon and steelhead may be once again spawning in the Mokelumne above Pardee, making the magic taking place in CDFW and EBMUD’s stewardship of the lower Mokelumne extend into some of the salmon’s historic upstream habitat.

    With that in mind, the Foothill Conservancy, East Bay Municipal Utility District, other nonprofit groups, businesses, state and local agencies, and tribal interests — working together as the Upper Mokelumne River Salmonid Restoration Team — have been exploring the potential to restore fall-run Chinook salmon to the upper Mokelumne River, according to a news release from the Conservancy and EBMUD.

    The  recently released study conducted by Cramer Fish Sciences shows that 13.7 miles of Mokelumne River above Pardee show the potential to support both spawning and rearing of chinook salmon.

    “The next step in exploring this potential will be a pilot project, likely reintroducing a small number of salmon upstream of Pardee Reservoir,” according to the Conservancy and EBMUD.

    “East Bay MUD and the California Department of Fish and Wildlife have done a great job of increasing the salmon population in the lower Mokelumne River through the operation of the Mokelumne River Fish Hatchery,” said Foothill Conservancy Vice-President Pete Bell. “For more than eight years in a row, the number of salmon returning to the hatchery exceeded its capacity.”

    “Those ‘excess’ fish could be available for direct reintroduction into the upper watershed without reducing the hatchery production. This new study shows that we may be able to return some of the returning salmon to their historic spawning habitat in the upper Mokelumne for the first time since Woodbridge and Pardee dams were built early in the last century,” said Bell.

    The study also points out that the reintroduction of salmon to historical habitats on the Mokelumne may have “profound cultural, economic and ecological benefits.” Spawning salmon also attract people for viewing, which could bring economic benefits from ecotourism. The study states:

    “Reintroduction of fall-run Chinook salmon to the Upper Mokelumne River offers an opportunity to provide access to over 27km (~17 miles) of historic habitat. The reintroduction of salmon to historical habitats may have profound cultural, economic and ecological benefits. Salmon are an integral part of West Coast culture, primarily with the native peoples of the Pacific Northwest and California and more recently, with hundreds of salmon festivals taking place each fall. Reintroducing salmon to historic habitats can potentially link cultures to lost traditions in the watershed.”

     

     

    Reintroducing salmon to the watershed could provide positive ecosystem-level impacts by restoring marine nutrients to the river and watershed and food for fish and wildlife, according to scientists.

    The Mokelumne’s Chinook salmon are critical to California’s recreational and commercial salmon fishery. The Central Valley salmon stocks generate millions of dollars every year from Morro Bay in the South to Shelter Cove in the north.

    “We’re glad to learn there’s still good salmon habitat in the Mokelumne River above the dams,” said McManus. “Researchers are proposing a first step to see if adult salmon can successfully be relocated there to spawn. Fish produced in the upper Mokelumne could benefit the salmon fishing industry, if paired with EBMUD’s successful hatchery program to release juvenile fish in the Western Delta. This program would provide valuable lessons that might be used on other California rivers.”

    Michelle Workman, Supervising Fisheries Biologist for East Bay Municipal Utility District, said the Upper Mokelumne Salmon Restoration Team has been “working diligently” to develop the science and engage multiple stakeholders and agencies to help move this process from planning to implementation.

    “We look forward to continuing this valuable collaboration for the benefit of the Mokelumne River fishery and for the enjoyment of a renewed public trust resource in the river above Pardee Reservoir,” said Workman.

    Grants from the Lower Mokelumne River Partnership and the Firedoll Foundation funded the salmon habitat study.

     

    Read the article at the source »

  • State environmental group wants old Scott Dam on Eel River removed to help salmon and steelhead

    March 16, 2019

    Santa Rosa Press Democrat by Guy Kovner (Josh Fuller)

    A state environmental group is calling for the removal of an old dam on the Eel River, contending it threatens the future of protected salmon and steelhead while acknowledging it is a key part of the North Bay’s water supply.

    Scott Dam, a 138-foot concrete dam erected in 1922, is one of five aging dams California Trout asserts are “ripe for removal” to benefit their natural surroundings and communities.

    The nearly 50-year-old nonprofit known as CalTrout said in its report, “Top 5 California Dams Out,” the Eel River represents “perhaps the greatest opportunity in California to restore a watershed to its former abundance of wild salmonids.”

    Scott Dam, located in Lake County’s portion of the Mendocino National Forest, has been a longstanding target of other groups, including Friends of the Eel River, who want steelhead, coho and chinook salmon to swim freely within the 288 miles of habitat in the Eel watershed blocked by the dam.

    The environmentalists see a “unique opportunity” to achieve their goal, as California’s largest utility PG&E, which has owned the dam as part of a small hydropower project since 1930, has filed Chapter 11 bankruptcy and abandoned plans to sell or seek relicensing of the project that diverts 20 billion gallons of water a year from the Eel to the Russian River at Potter Valley.

    Eel River interests have considered the diversion a form of theft, while the water is critical to towns and ranches on the upper Russian River from Potter Valley to Healdsburg and part of the water supply for 600,000 residents in Sonoma and Marin counties.

    How the future of the Potter Valley Project will play out over the next 18 months to two years is unclear, but it appears likely to result in either decommissioning or relicensing of the project, which includes a small powerhouse and two Eel River dams.

    The bottom line is either PG&E or a new owner of the project may face a choice between paying more than $90 million for a fish ladder at Scott Dam or about $70 million to remove it.

    North Coast Rep. Jared Huffman, D-San Rafael, and CalTrout both say federal officials are likely to require “volitional fish passage” at Scott Dam, enabling the threatened salmon and steelhead adults to swim freely to their spawning grounds and juvenile fish to get out to the Pacific Ocean.

    “There’s no way around it,” Huffman said.

    The National Marine Fisheries Service, under federal law, has the authority to require fish passage at hydropower projects that are either changing hands or shutting down, said Josh Fuller, an agency biologist based in Santa Rosa.

    Fuller, who is involved in process, declined to name a preferred fate for the dam but said it should ensure the dwindling number of Eel River fish are “on a recovery trajectory.”

    “We’re going to have to have some sort of fish passage at the facility,” he said. There are numerous ways to accomplish it, including trapping fish and trucking them around the dam, but Marine Fisheries favors volitional passage because it involves “less human intervention” in the fish population. Fuller said.

    “It’s fair to say the status quo will not work,” he said.

    Read the article at the source »

  • Heavy rains could harm Marin salmon, steelhead recovery, surveyors say

    March 8, 2019

    Marin Independent Journal By Will Houston

    The deluge of rain this winter may act as a double-edged sword for the recovery of protected fish runs in the Lagunitas Creek watershed, according to Marin County fish surveyors.

    The strong rains ramped up stream flows, allowing spawning fish such as steelhead and endangered coho salmon to reach their spawning grounds. However, the historic loss of floodplains by development and dams in the watershed has resulted in rainfall concentrating into much stronger flows, which can scour creek beds where steelhead and salmon bury their egg nests, also called redds.

    This year is being called the watershed’s best spawning season for endangered coho salmon in 12 years, and surveyors are concerned that recent powerful storms and resulting high flows could harm the newly hatched salmon fry and the thousands of precious eggs incubating in local creek beds.

    Michael Reichmuth, fisheries biologist for the Point Reyes National Seashore, said the flows he and other researchers saw on the Olema Creek tributary were at a level they would normally see once every decade or so.

    “Some may wonder what this means to the salmon,” Reichmuth wrote in an email. “For adult steelhead it means plenty of habitat to work with for spawning if they are entering the creeks now. For the eggs and fry that are currently emerging from nesting sites it could mean the end of their life.”

    The rains also engorged Lagunitas Creek to peak flows of about 4,100 cubic feet per second, which is the level seen every eight years or so, according to Marin Municipal Water District aquatic ecologist Eric Ettlinger.

    “Past floods like this have mobilized streambed sediment, either uncovering or entombing incubating salmonid eggs, and resulted in survival rates of only about 2 percent,” Ettlinger said.

    But Ettlinger said there are encouraging signs that this will remain a good year for coho recovery. About 600,000 coho eggs are estimated to have been deposited during this year’s winter coho run, and Ettlinger said survival rates don’t have to be high to produce normal numbers of fry.

    “The biggest risk now is that a late-season storm will wash out coho fry after they’ve emerged from the gravel,” Ettlinger wrote in an email.

    Downed trees, wood and other debris in the creek can provide shelter for the young rearing fish during floods and strong flows.

    “In the summer time when the flows have receded we will be able to take inventory on the habitat and remaining fry to give us insight on how detrimental these floods were on the population,” Reichmuth said.

    While the coho spawning season ended last month, steelhead spawning is ongoing. Surveyors haven’t had many chances to count fish because of the storms and high flows. By the end of February surveyors had found about 99 steelhead redds, which Ettlinger says is average.

    National park fish surveyors have only been able to conduct a few surveys on the Redwood Creek watershed and on the Chelda Creek tributary, but have not been able to go out for several weeks due to the high flows. Total counts so far show 45 steelhead adults, one carcass and 13 redds on Redwood Creek. One steelhead and one steelhead redd were also found on Chelda Creek.

    Both Reichmuth and Ettlinger said they hope to do more surveying once the flows recede.

     

    Read the article at the source »

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