{"id":412435,"date":"2024-03-06T05:31:00","date_gmt":"2024-03-06T13:31:00","guid":{"rendered":"https:\/\/calmatters.org\/?p=412435"},"modified":"2024-03-05T18:51:56","modified_gmt":"2024-03-06T02:51:56","slug":"california-klamath-river-salmon-dead","status":"publish","type":"post","link":"https:\/\/calmatters.org\/_zh\/environment\/2024\/03\/california-klamath-river-salmon-dead\/","title":{"rendered":"\u514b\u62c9\u9a6c\u65af\u6cb3\u9c91\u9c7c\u5927\u91cf\u6b7b\u4ea1\uff0c\u8fd9\u5f88\u60b2\u60e8\u3002\u8fd9\u662f\u53ef\u4ee5\u9884\u89c1\u7684\u5417\uff1f"},"content":{"rendered":"
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Large numbers of young Chinook salmon were found dead two days after being released from a state hatchery. Biologists say they were shocked by the die-off \u2014 but it was a predictable aftermath of human efforts to restore nature. <\/p>\n\t\t\t\t\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\n\t\t\n

\u4e00\u4e2a recent large die-off of young salmon released into the Klamath River<\/a> shocked and dismayed state biologists, reinforcing that human efforts to restore nature and undo damage can be unpredictable and difficult  to control. <\/p>\n\n\n\n

The tiny Chinook salmon turned up dead downriver just two days <\/strong>after they were released from the California Department of Fish and Wildlife\u2019s brand new Fall Creek Fish Hatchery, built to supply the Klamath River as it undergoes the largest dam removal in history.  <\/strong><\/p>\n\n\n\n

\u8fd9 $35 million state hatchery,<\/a> on a tributary just upstream of Iron Gate dam in Siskiyou County, was constructed to help the river’s threatened coho<\/a> and dwindling fall-run chinook salmon, a mainstay of commercial and recreational fishing and tribal food supplies.<\/p>\n\n\n\n

The hatchery\u2019s first release ended with an unknown number of the 830,000 young Chinook salmon found dead, their eyes bulging, in a federal sampling trap about 9 miles below the dam.<\/p>\n\n\n\n

State officials called it \u201ca large mortality,”<\/a> but said there\u2019s no official count yet and released no additional details about the size of the die-off.<\/p>\n\n\n\n

California\u2019s fish and wildlife officials said they suspect \u201cgas bubble disease,\u201d<\/a> a condition similar to decompression sickness in scuba divers, is to blame \u2014 likely caused when the salmon traveled through a 9-foot-wide tunnel out of Iron Gate dam to reconnect with the Klamath downriver. <\/p>\n\n\n\n

Gas bubble disease in fish is caused by \u201cenvironmental or physical trauma often associated with severe pressure change,\u201d officials said.<\/p>\n\n\n\n

Jason Roberts, inland fisheries program manager with the state agency, said it\u2019s an outcome that state, federal, and tribal scientists involved in the decision didn\u2019t anticipate.<\/p>\n\n\n\n

\u201cThe basin co-managers made the best decision they could with the information that they had, and unfortunately, it did not go well,\u201d Roberts said. \u201cI don’t think anyone thought water going through this tunnel would cause gas bubble disease, or we obviously wouldn’t have done it.\u201d<\/p>\n\n\n\n

\u201cYou see gas bubble disease at hatcheries when there’s flood flows and there’s tons of water,\u201d he added. \u201cI think everyone assumed, given Iron Gate reservoir was basically drained, that there wouldn’t be a problem.\u201d<\/p>\n\n\n\n

\u201cI don’t think anyone thought water going through this tunnel would cause gas bubble disease, or we obviously wouldn’t have done it.\u201d<\/p>Jason Roberts, california department of fish and wildlife<\/cite><\/blockquote><\/figure>\n\n\n\n

It was a tragic, heartbreaking event for the fish biologists and a setback for a costly and high-profile project: The state had hatched and raised the salmon, then released them into a place where they died almost immediately. <\/p>\n\n\n\n

\u201cI feel really bad for the fish. And I feel really bad for my staff that spend all their time taking care of these fish, and for all the partners and stakeholders that are counting on us,\u201d Roberts said.<\/p>\n\n\n\n

Ecologists say<\/a> that taking steps to restore nature or undo environmental damage \u2014 such as constructing new wetlands to replace bulldozed ones, building passages for wildlife and providing new habitat for endangered species \u2014 can be unpredictable and have unintended consequences. Failure is always a possibility.<\/p>\n\n\n\n

Toz Soto, fisheries manager for the Karuk Tribe, commended the efforts to remove the dams and restore the river. The Karuk Tribe\u2019s ancestral territory<\/a> covers hundreds of miles along the middle of the Klamath River, and salmon are a key part of their traditional diet<\/a>.<\/p>\n\n\n\n

\u201cWhile there is a level of uncertainty in anything you do, especially a massive dam removal project like this, they\u2019ve done a really good job of predicting what\u2019s going to happen, especially with sediment movement and transport, poor water quality,\u201d Soto said. Despite the tragedy, he said, \u201cI’m overall really happy with the outcome so far.\u201d<\/p>\n\n\n\n

No wild salmon were harmed. And the consequences aren\u2019t expected to be catastrophic for the Klamath hatchery project.<\/p>\n\n\n\n

\u201cThis is just a sad reminder of the harm that these dams have caused, and continue to cause.\u201d<\/p>Robert Lusardi, Uc davis Department of Wildlife, Fish, and Conservation Biology <\/cite><\/blockquote><\/figure>\n\n\n\n

The hatchery is still raising 3.27 million healthy chinook salmon, more than the state\u2019s annual goal of 3.25 million, to be released into the river. From now on, officials plan to bypass the dam and truck the remaining fish downriver.<\/p>\n\n\n\n

\u201cWe believe the effects to salmon populations will therefore be minimal,\u201d said Michael Belchik, senior water policy analyst with the Yurok Tribe, the largest tribe in California with a reservation that spans a 45-mile stretch of the lower Klamath River<\/a>. <\/p>\n\n\n\n

And by the end of the year, Iron Gate dam should be gone. <\/p>\n\n\n\n

\u201cIron Gate\u2019s killed its last salmon,\u201d Belchik said. <\/p>\n\n\n\n

The die-off came as four aging hydroelectric dams<\/a> are being cleared from the Klamath River\u2019s path, reconnecting a river that has been divided for over a century. The reservoirs have been drained<\/a>, and the river is reclaiming its track. One of the dams is already gone. <\/p>\n\n\n\n

California tribes and conservation groups have been fighting for dam removal for decades. Reconnecting hundreds of miles of habitat and restoring more natural flows to the river is expected to help revive the area\u2019s salmon. <\/p>\n\n\n\n

The die-off also came amidst increased scrutiny of the dam removal, which opponents in Siskiyou County have called \u201cthe largest, most devastating dam removal experiment in modern history.\u201d They warn that it is creating a \u201criver of death<\/a>\u201d that will unleash sediment and other materials into the river \u2014 jeopardizing the fish.<\/p>\n\n\n\n

\"A
A view of Iron Gate dam, one of three hydroelectric dams being removed on the Klamath River, on July 17, 2023. Photo by Semantha Norris, CalMatters<\/figcaption><\/figure>\n\n\n\n

But wildlife officials say the river\u2019s sediment and dissolved oxygen levels were suitable <\/em>for releasing the fish<\/a> and weren\u2019t a cause of the die-off. They say it\u2019s likely that conditions within the Iron Gate dam\u2019s tunnel killed the salmon \u2014 reinforcing the danger of these vestigial structures. <\/p>\n\n\n\n

\u201cThis is just a sad reminder of the harm that these dams have caused, and continue to cause,\u201d said Robert Lusardi<\/a>, assistant professor of freshwater ecology at the University of California, Davis. \u201cIt does speak to the need to immediately remove the dam infrastructure from the Klamath River.\u201d <\/p>\n\n\n\n

Mark Bransom, CEO of the Klamath River Renewal Corporation, the nonprofit formed to oversee the removal effort, said it also speaks to the challenge of undoing decades of human environmental interference. <\/p>\n\n\n\n

\u201cWe cannot unwind over 100 years of environmental damage overnight,\u201d Bransom said. \u201cWe really do have to take a little bit longer view of what restoration means when we are trying to unspool a century’s-worth of impacts to the environment and to the communities who depend on a healthy river.\u201d<\/p>\n\n\n\n

From healthy hatchery newborns to dead in the river<\/h3>\n\n\n\n

The salmon were healthy when they left the hatchery on Feb. 26. Only months old and an inch or two long, they were released as scheduled to give the remaining fish in the hatchery ample room to grow.<\/p>\n\n\n\n

The salmon fry traveled down Fall Creek and into the Klamath River as it snakes through the footprint of the now-drained Iron Gate reservoir, before swimming through the roughly 200-foot long, 9 foot-wide tunnel through Iron Gate dam and back into the Klamath River. <\/p>\n\n\n\n

They began showing up dead two days later in a U.S. Fish and Wildlife Service sampling trap miles downstream. <\/p>\n\n\n\n

Roberts said their bulging eyeballs were a telltale sign of gas bubble disease. A definitive confirmation, though, is unlikely from carcasses that traveled so far.  <\/p>\n\n\n\n

Much like with the bends, gas bubble disease occurs when air bubbles form in blood and tissue<\/a>. In fish, it can be caused by severe pressure changes or in water containing excess levels of gases. <\/p>\n\n\n\n

Bransom said pressure conditions were normal where the river flows into the tunnel, which was flowing only about half full, he said.  <\/p>\n\n\n\n

\u201cThere has been no definitive conclusion that this was gas bubble disease and that the tunnel was responsible,\u201d Bransom said. \u201cIt\u2019s possible there was some hydraulic condition inside of the tunnel that produced a high pressure zone, meaning higher than atmospheric pressure, but again we don\u2019t have any evidence of that, and we don\u2019t know what the level of mortality actually was.\u201d <\/p>\n\n\n\n

Roberts said it\u2019s \u201cnear impossible\u201d to put a number on how many fry died at this point. <\/p>\n\n\n\n

\u201cIt might not ever be a firm number that anyone knows,\u201d he said. \u201cThe majority of the fish in the trap that were fry-sized were deceased, and they had visual signs of gas bubble disease. Therefore, it’s a safe assumption to think that if those fish swam through the tunnel, other fish that swim through the tunnel likely experienced a high rate of mortality as well.\u201d<\/p>\n\n\n\n

He added, \u201cthankfully we have an extra 850,000 fish on hand so that will help offset the loss of these fish \u2014 from a production standpoint.\u201d <\/p>\n\n\n\n

\u201cSo far, we\u2019ve been finding normal fish, healthy fish. So that\u2019s really good \u2014 that the wild fish are not affected by this.\u201d<\/p>Toz Soto, Karuk Tribe Fisheries<\/cite><\/blockquote><\/figure>\n\n\n\n

Still, the loss comes at a delicate time for the Klamath dam removal effort,<\/a> which began in earnest last summer when the first dam was demolished<\/a>.<\/p>\n\n\n\n

\u201cWhile the project’s going through a lot of scrutiny, this is just another thing for naysayers to pile on to,\u201d said Curtis Knight, executive director of California Trout<\/a>, a conservation organization. \u201cBut I think it’s important to note the dam is not going to be there much longer \u2014 that\u2019s what caused these fish to die, and conditions in the river below are improving.\u201d<\/p>\n\n\n\n

The dam removal nonprofit group reported on Feb. 15 that 5 million cubic yards of sediment is expected to be released during the months-long drawdown process<\/a>, and that there had been a significant die-off in the reservoirs during the drawdown. Bransom said they were non-native fish that had thrived in the warm water and that the deaths were expected during the drawdown.<\/p>\n\n\n\n

But officials said sediment levels and dissolved oxygen were reading at suitable levels when the fish were released. Also, older fish that had traveled from downstream of the dam and were snagged in the same sampling trap showed no signs of the disease, which suggested that river conditions were not to blame. <\/p>\n\n\n\n

And conditions are improving, even over the last month, said Soto of the Karuk Tribal Fisheries Program.<\/p>\n\n\n\n

\u201cOur crews have been out sampling the main stem below the dam because we have concerns with sediment transport and poor water quality, so we really wanted to know how wild salmon juveniles are doing,\u201d Soto said.  \u201cAnd so far, we\u2019ve been finding normal fish, healthy fish. So that\u2019s really good \u2014 that the wild fish are not affected by this.\u201d<\/p>\n\n\n\t\n\t\t

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Saving salmon: Newsom unveils blueprint for ending decades-long decline\u00a0<\/a><\/h3>\t\t\t\t\t\t\t\t\t\t
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