Tag Archives: chinook

Survivor Salmon that Withstand Drought and Ocean Warming Provide a Lifeline for California Chinook

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October 28, 2021, fisheries.noaa.gov

NOAA Fisheries recovery goals include reintroduction to save the late-migrating fish.

A late-migrating spring run Chinook salmon from one of the few Northern California creeks that remain without dams. Credit: Jeremy Notch/UC Santa Cruz.

In drought years and when marine heat waves warm the Pacific Ocean, late-migrating juvenile spring-run Chinook salmon of California’s Central Valley are the ultimate survivors. They are among the few salmon that return to spawning rivers in those difficult years to keep their populations alive. This is according to results published today in Nature Climate Change.

The trouble is that this late-migrating behavior hangs on only in a few rivers where water temperatures remain cool enough for the fish to survive the summer. Today, this habitat is primarily found above barrier dams. Those fish that spend a year in their home streams as juveniles leave in the fall. They arrive in the ocean larger and more likely to survive their 1–3 years at sea.

Scientists examined the ear bones of salmon, called otoliths. These bones incorporate the distinctive isotope ratios of different Central Valley Rivers and the ocean as they grow sequential layers. They looked at Chinook salmon from two tributaries of the Sacramento River without dams that begin beneath Lassen Peak, north of Sacramento. Late-migrating juveniles from Mill Creek and Deer Creek returned from the ocean at much higher rates than more abundant juveniles that leave for the ocean earlier in the spring.

Scientists examined otoliths, the ear bones of salmon, to understand the migration timing of fish that survived drought and poor ocean conditions. Credit: George  Whitman and Kimberly Evans/UC Davis

The different timing characteristics of the fish are referred to as “life-history strategies.” Those with a late-migrating life history strategy represented only about 10 percent of outgoing juveniles sampled in fish monitoring traps. However, they were about 60 percent of the returning adult fish across all years, and more than 96 percent of adults from two of the driest years.

“Some years the late migrants were the only life-history strategy that was successful,” said Flora Cordoleani, lead author of the research and associate project scientist with NOAA Fisheries and UC Santa Cruz. “Those fish can make it through the difficult drought conditions on the landscape because they come from the few remaining rivers with accessible high-elevation habitats where water is cool enough through the summer.”

Recovery Strategies Include Reintroduction

The finding underscores the importance of providing secure cool-water habitat for fish so they can survive difficult conditions during drought and ocean warming, said Rachel Johnson, a NOAA Fisheries research scientist, UC Davis researcher and senior author of the study. “Most salmon blocked from their historical habitats appear to migrate just too early and perish once they encounter the warmer water temperatures during droughts.”

“It appears the late-migrating life history has evolved as an insurance policy against the unfavorable spring river conditions that occur during droughts,” said Corey Phillis, a researcher at the Metropolitan Water District of Southern California and co-author on the study.

The study also projected how Central Valley river temperatures would rise with climate change, leaving only a few higher-elevation rivers cool enough to still sustain salmon. Many of those areas are above existing dams without fish passage.

NOAA Fisheries has outlined reintroduction of salmon to cold-water rivers above dams as a critical recovery strategy for endangered Sacramento River winter-run Chinook, a NOAA Fisheries Species in the Spotlight. The reintroduction of threatened spring-run Chinook salmon to the San Joaquin River watershed has taken hold. Offspring of reintroduced spring-run Chinook salmon are now returning from the ocean. NOAA Fisheries is also advancing the reintroduction of spring-run Chinook to the upper Yuba River upstream of Englebright Dam.

The study found that temperatures would remain cool enough for salmon to survive in the north Yuba River as the climate changes.

“We need to reconnect salmon to their historical habitats so they can draw from their own climate-adapted bag of tricks to persist in a warming world,” Johnson said.

By growing for a year in their home river, the later-migrating fish head for the ocean bigger than the others and in cooler temperatures. That way, more survive and return to rivers to spawn when marine heatwaves warm the ocean and depress salmon survival. A Marine Heatwave Tracker developed by the Southwest Fisheries Science Center shows that heatwaves have become an increasing presence in the Pacific Ocean in the last decade.

A returning adult spring run Chinook salmon leaps from the water in California’s Central Valley. Credit: Carson Jeffres/UC Davis

Heatwaves Reduce Survival

A large heatwave currently stretching across the Pacific off Northern California and Oregon, as shown by the tracker, may affect salmon survival. Warmer ocean waters are generally less productive, reducing salmon survival and depressing returns to rivers.

NOAA Fisheries’ Northwest Fisheries Science Center has developed a “stoplight chart” that projects survival of different salmon species based on different factors at play in the ocean.

The researchers highlighted the importance of protecting varied life histories that may help their species survive climate change. This is particularly true in California, which is at the southern end of the range of many salmon and at the edge of conditions where they can survive.

“The rarest behaviors observed today may be the most important in our future climate,” said Anna Sturrock of the University of Essex and a co-author of the research.

“We show for the first time that the late-migrating strategy is the life-support for these populations during the current period of extreme warming,” the scientists concluded. “As environmental conditions continue to shift rapidly with climate change, maximizing habitat options across the landscape to enhance adaptive capacity and support climate-resilient behaviours may be crucial to prevent extinction.”

Researchers included:

  • NOAA Fisheries’ Southwest Fisheries Science Center
  • UC Santa Cruz
  • UC Davis
  • University of Essex
  • Metropolitan Water District of Southern California
  • Mediterranean Institute of Oceanography
  • Lawrence Livermore National Laboratory

More Information

Read original story on “Survivor Salmon” and explore more on NOAA Fisheries

 

Fight Ocean Acidification: Yes on WA Initiative 1631

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This commentary appears in the October 2018 issue of Pacific Fishing magazine

By Matt Marinkovich

In the mid-1980s, when I started seining with my dad for Fraser River sockeye, the Puget Sound fishery was already declining. But lately the consequences of a fraying marine food web are spreading far beyond the fishing fleet.  Living in Friday Harbor, I have a front row seat.

That’s why I will vote for Washington’s Initiative 1631 in November. This ballot measure will deeply reduce the biggest source of pollution that degrades our waters: carbon dioxide (CO2) from burning coal, oil and gas.

I’ve experienced some of the harm first hand. Local salmon stocks kept dwindling, so like many fishermen I migrated north. Now I fish in Bristol Bay, while back home whale watch boats and yachts have replaced fish boats in the harbor.  Now they are worried too.

The endangered southern resident Orca whales aren’t getting enough fish to sustain themselves. These whales haven’t successfully raised a calf in over three years.

Is anyone surprised? Our resident orcas eat almost exclusively Chinook salmon. Just since I was a teenager, catch and escapement of these fish have dropped by more than half.  Chinook in Puget Sound are down to about 10% of historic levels.

Scientists say the young Chinook themselves may be starving, especially when they first enter the Sound. November’s ballot measure offers a chance to tackle what might be the biggest problem —while we still can.

Carbon dioxide from burning fossil fuels mixes into the water and acidifies Puget Sound. Scientists at the UW Labs in Friday Harbor have measured CO2-driven acidification at extremes that most marine waters aren’t expected to see for generations. It is dissolving the shells of tiny floating snails called pteropods, a major prey for young salmon. High CO2 and warm waters are fueling toxic algae that displace nutritious plankton eaten by salmon.  Toxic algae are also forcing harvest closures in Dungeness crab and shellfish beds. Scientists say the impacts will keep getting worse until we confront the root cause.

Not every attempt to  “cure” this problem deserves support from fishermen. Initiative 1631 does. It is a powerful and affordable tool to slash the underlying CO2 emissions.

Fishermen and tribal leaders intervened to improve this ballot measure, so resource-dependent coastal people get a fair shake. The Working Group on Seafood and Energy, the only fisheries trade association focusing on carbon emissions, endorsed the initiative and provided a lot of information for this article.

The measure will achieve deep emission cuts at low costs. It will also help fishermen and others afford to do their part, instead of just sticking them with a bigger fuel bill. This initiative will impose a modest “carbon price” on most fuels. Then it uses the money to fix the problem—investing it to help ordinary people boost fuel efficiency, reduce emissions, and adapt.

This is a much stronger, fairer approach than the “carbon tax” (and mis-targeted revenue giveaway) that Washington voters rejected in 2016. I-1631’s “price and invest” approach provides funding that communities and businesses can use to build solutions that also benefit local industries. The money can build cold storages in coastal communities to eliminate trucking fish hundreds of miles to facilities in urban centers; retrofit vessels and vehicles to make them more fuel-efficient; and protect carbon-storing forested watersheds to ensure stable water supplies and draw down carbon.

Fishermen and tribes insisted on strong measures to ensure carbon revenues won’t be diverted and squandered. Now the initiative includes multiple layers of accountability, starting with the mechanism for collecting revenue: it’s a fee, not a tax. Legally, that means the money can only be spent to reduce emissions or to help people adapt to the impacts.

Marine fuels are exempt from the extra carbon price, so fishermen won’t pay a dime more at the fuel dock. Other fuels will be charged $15 per ton of carbon (around 14 cents a gallon of gas or diesel). That price rises at $2 (per ton) a year, with the proceeds invested in solutions. The price stops rising in 2035 if the state is hitting its emission targets, which it should, since most of the money will go directly into emission reductions.

This fee-based policy makes way more sense than the “carbon tax” voters rejected in 2016. This time, the initiative won’t give away money for tax breaks for big business and unfocused “rebates” to low-income people. Instead, I-1631 dedicates the revenue to actually fix the problem— isn’t that where the money should go?

Washington isn’t going it alone. Dozens of countries (including China) and state and local governments that represent about half the world economy have already enacted similar “price-and-invest” policies. That’s the kind of teamwork it takes to make a difference.

Killer whales and fishermen share a common interest in making sure the ocean can continue to support the fish we hunt.  We need a strong, fair policy that will cut emissions. We need a policy like Washington’s I-1631.

Matt Marinkovich grew up fishing sockeye salmon on Puget Sound, fishes Bristol Bay today, and runs Matt’s Fresh Fish, selling direct to consumers and restaurants. He is an active advocate for a healthy Salish Sea.

Note: Global Ocean Health’s Brad Warren, on behalf of the Working Group on Seafood and Energy, worked with Matt Marinkovich to provide policy research and analysis for Matt’s article