Killer whales prefer to eat only the biggest, juiciest Chinook salmon they can find. The larger the fish, the more energy a whale can get for its meal.

Each year these top ocean predators consume more than 2.5 million adult Chinook salmon along the West Coast. Except for the endangered in Washington, all other fish-eating orca populations that live along the coast, called “residents,” are growing in number. along the British Columbia coast number more than 300 whales, for example, while Alaska orcas are close to 2,300 individuals.

But large, old Chinook salmon that orcas crave have mostly disappeared from the West Coast. A new 91̽�� and NOAA study points to the recent rise of resident killer whales, and their insatiable appetite for large Chinook salmon, as the main driver behind the decline of the big fish.

The were published Dec. 16 in the Proceedings of the National Academy of Sciences.

“We have two protected species, resident killer whales and Chinook salmon, and we are trying to increase abundances of both — yet they are interacting as predator and prey,” said lead author , a research scientist at the 91̽��School of Aquatic and Fishery Sciences. “Killer whales don’t show a lot of interest in Chinook until they reach a certain size, and then they focus intensely on those individuals.”

Chinook salmon are born in freshwater rivers and streams, then migrate to the ocean where they spend most of their lives feeding and growing. Each population’s lifestyle in the ocean varies, mainly depending on what stream they were born in and where they can find food. Washington and Oregon fish often migrate thousands of miles north to the Gulf of Alaska where they feed and fatten up before embarking on their migrations back to rivers in the Pacific Northwest to spawn.

As they return south to spawn in their home streams, Pacific Northwest salmon pass through the feeding grounds of several different killer whale populations, which appear to have a keen affinity for big Chinook. It’s possible these thriving killer whales are essentially stealing a meal from the southern resident orca population, which is struggling to maintain 73 individuals.

“We like to think of the Pacific Ocean as a really big place, but that’s because we are really lousy swimmers. For killer whales and salmon, it’s not a big place,” said co-author , a 91̽��professor of aquatic and fishery sciences. While different orca populations avoid each other in the ocean, they inherently overlap their whole lives when competing for the same prey, he explained.

It used to be common to find Chinook salmon 40 inches or more in length, particularly in the Columbia River or Alaska’s Kenai Peninsula and Copper River regions. The average declines in body size — about 10% in length and 25% to 30% in overall weight — could have a long-term impact on the productivity of Chinook salmon populations. Smaller females carry fewer and smaller eggs, so over time the number of fish that hatch and survive to adulthood may decrease.

Resident orcas usually don’t go for Chinook until they reach about 25 inches in length, and they really prefer fish that are over 30 inches long, the researchers said.

The research team analyzed nearly 40 years of data from hatchery and wild Chinook populations from California to Alaska, looking broadly at patterns that emerged over the course of four decades and across thousands of miles of coastline. They analyzed whether fishing pressure played a role in why the biggest Chinook have disappeared, and also considered other factors like changing ocean conditions, and feeding from other marine mammals such as sea lions and seals.

While fishing likely played a role in the decline of large Chinook in the past, fishing pressure since the 1970s has been reduced through more stringent fishery regulations. In the same period, resident killer whales have tripled in abundance.

“Something has to be affecting the survival rates of the oldest fish,” Schindler said. “It’s clear there are lots of unanswered questions, but if you take a weight-of-evidence approach, most arrows are pointing to marine mammals — and killer whales, in particular.”

Still, the researchers caution there are many remaining unknowns, such as why there were so many large Chinook in the past. It’s possible killer whales have a bigger effect now than they did historically, when there were so many more fish in the ocean, explained co-author , a research scientist at NOAA’s Northwest Fisheries Science Center. Declines in the ocean abundance of Chinook salmon as a result of other factors may be intensifying the size-selective effects of orca predation.

“We have seen clear success stories in the rebound of predator species like killer whales,” Ward said. “We’re trying to understand the suite of tradeoffs we face when we have these increases in predator populations.”

The study’s findings reflect a North Pacific ecosystem that is fluid and interconnected, and doesn’t recognize state and national borders, or their associated management practices.

“This study highlights the fact that local management strategies need to be put in a much broader spatial context,” Ohlberger said. “In this case, that means the whole coast, because that’s where the fish migrate.”

Other co-authors are , 91̽��professor of aquatic and fishery sciences, and , a former 91̽��graduate student who is now at Utah State University.

This research was funded by the Pacific States Marine Fisheries Commission and the North Pacific Research Board.

For more information, contact Ohlberger at janohl@uw.edu, Schindler at deschind@uw.edu and Ward at eric.ward@noaa.gov.

Reporters who wish to use the MOHAI historical image in this press release must contact MOHAI to determine licensing fees: 206-324-1126 x140 or adam.lyon@mohai.org

A new  released July 1 in Nature Climate Change gives hope for coral reefs.

Launched by the nonprofit , with lead and senior authors at the 91̽��, the study is one of the first to demonstrate that management that takes evolution and adaptation into account can help rescue coral reefs from the effects of climate change.

Importantly, the results show that by making smart decisions to protect reefs today, conservation managers can generate the conditions that can help corals adapt to rising temperatures.

“It is well documented that climate change is causing corals to die off at an unprecedented rate, but our study provides tools that offer promise for their survival,” said , co-author and program director at the Coral Reef Alliance. “Our results show that when evolution is enabled, conservation efforts can help corals adapt to rising temperatures.”

Contrary to approaches that are popular today, such as focusing protection on reefs in cooler water, the  shows that protecting diverse reef habitat types across a spectrum of ocean conditions is key to helping corals adapt to climate change.

“We found that a diversity of reef types provides the variety that evolution depends on,” said co-author , associate professor at Rutgers University. “Hot sites are important sources of heat-tolerant corals, while cold sites and those in between can become important future habitats. Together, a diversity of reef types act as stepping stones that give corals the best chance for adapting and moving as climate changes.”

Key to successful evolution is management that improves local conditions for reefs by effectively reducing local stressors, such as overfishing and water pollution. However, the authors caution that not all management strategies are created equal.

“We used mathematical models to test the effects of management choices on coral reef outlooks,” said lead author , a postdoctoral researcher at the 91̽��School of Aquatic and Fishery Sciences. “We found that corals in well-managed areas act as a source of baby corals in the future, essentially rescuing reefs after the climate stabilizes. Without both evolution and management, the corals in our model were unable to survive rising temperatures.”

Coral reefs are one of the most diverse ecosystems on the planet and support the livelihoods of over 500 million people. Globally, they are estimated to be worth $375 billion per year. The study shows that managing reefs to facilitate evolution today and in the future can enhance their prospects for long-term survival. This means creating managed area networks that contain a diversity of coral types and habitats and effectively reduce local stressors.

“This study shows that we know enough of the science to act — and with the effects of climate change only increasing, we have little time to waste,” Colton said.

The study is the result of a collaborative research program launched by Colton and Michael Webster of the Coral Reef Alliance. Other co-authors and project collaborators are and , both 91̽��professors of aquatic and fishery sciences; of Stanford University; and of University of Queensland.

The research was funded by the Gordon and Betty Moore Foundation.

This story was adapted from a Coral Reef Alliance .

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For more information, contact lead author Tim Walsworth at tewals@uw.edu; or co-authors Daniel Schindler at deschind@uw.edu and Tim Essington at essing@uw.edu.

Contact Yasmeen Smalley-Norman at Coral Reef Alliance for interviews with researchers at the nonprofit: ysmalleynorman@coral.org or 713-249-5084.

Photos and videos are available to download on the Coral Reef Alliance’s .

An ample buffet of freshwater food, brought on by climate change, is altering the life history of one of the world’s most important salmon species.

Sockeye salmon in Alaska’s Bristol Bay region are skipping an entire year in freshwater because climate change has produced more favorable conditions in lakes and streams, which allow the young fish to grow and put on weight much faster. Previously, these fish would spend up to two years in their birth lakes before heading to the ocean, where they feed and reach maturity two to three years later. Now they are more likely to head out to sea after only one year.

These were published May 27 in Nature Ecology & Evolution by 91̽�� researchers.

“Climate change is literally speeding up the early part of their lifecycle across the whole region,” said senior author , a 91̽��professor in the School of Aquatic and Fishery Sciences. “We know climate warming is making rivers more productive for the food juvenile salmon eat, meaning their growth rate is speeding up. That puts the salmon on a growth trajectory that moves them to the ocean faster.”

But this “jumpstart” in freshwater doesn’t necessarily benefit salmon in the long run. The same fish are now spending an extra year in the ocean, taking longer to grow and mature. This extra year at sea is likely caused by climate stressors, as well as other fish: In the ocean, wild sockeye compete for food with close to 6 billion hatchery-raised salmon released each year throughout the North Pacific Ocean. That number has grown steadily since the 1970s, when only half a billion hatchery salmon were released.

“Hatchery fish have really changed the competitive environment for juvenile salmon in the ocean,” said lead author , a postdoctoral researcher at the University of Michigan who completed this work as a doctoral student at the UW. “In Bristol Bay, the habitat is totally intact and fisheries management is excellent, but these fish are living in lakes warming with climate change, then competing with other salmon for food in the ocean.”

The researchers drew on nearly 60 years of Bristol Bay sockeye data to tease out these changes over time, including information gathered by scientists and students in the UW’s . Close to half of the world’s wild sockeye is caught from this region, and more than 40 million fish usually return each year to Bristol Bay’s nine river systems to spawn.

Higher temperatures in the region have caused lakes and rivers to warm up earlier each spring, fueling the growth of tiny plankton that young sockeye eat. This extra food essentially fattens up the fish a year earlier, triggering their migration to the ocean.

This trend could negatively impact the resiliency of the Bristol Bay sockeye population, the authors said. Before, not every fish in a particular “age class” would migrate to the ocean in the same year, and any given year would see fish of different ages moving out to sea. This diversity of ages has helped the species navigate risks and survive.

But now, most sockeye are migrating at the same time, as 1-year-olds. This could devastate an entire age class if the ocean conditions happen to be poor one year. Additionally, scientists don’t know how many salmon the North Pacific can actually support.

“With climate change, is there a limit to how productive the ocean will become? We just don’t know where there’s a tipping point, especially as we fill the ocean with hatchery competitors,” Schindler said. “We need to be really cognizant about overstressing the marine resources that support wild salmon.”

Co-author on the study is , a research scientist at the 91̽��School of Aquatic and Fishery Sciences.

The study was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.

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For more information, contact Cline at tjcline@umich.edu or 608-381-0667 and Schindler at deschind@uw.edu or 907-842-5380.

Chemical signatures imprinted on tiny stones that form inside the ears of fish show that two of Alaska’s most productive salmon populations, and the fisheries they support, depend on the entire watershed.

Sockeye and Chinook salmon born in the Nushagak River and its network of streams and lakes in southwest Alaska use the whole basin as youngsters when searching for the best places to find prey, shelter and safety from predators. From birth until the fish migrate to the ocean a year later is a critical period for young salmon to eat and grow.

By analyzing each fish’s ear stone — called an — scientists have found that different parts of the watershed are hot spots for salmon production and growth, and these favorable locations change year to year depending on how climate conditions interact with local landscape features like topography to affect the value of habitats.

The new , led by the 91̽��, appears online May 23 in Science.

“We found that the areas where fish are born and grow flicker on and off each year in terms of productivity,” said lead author , a postdoctoral researcher at the 91̽��School of Aquatic and Fishery Sciences. “Habitat conditions aren’t static, and optimal places shift around. If you want to stabilize fish production over the years, the only strategy is to keep all of the options on the table.”

The Nushagak River watershed is the largest river basin in the Alaska’s , which supports the biggest sockeye salmon fishery in the world and provides about 50 percent of wild sockeye globally. It is also known for its large run of Chinook salmon.

The new study coincides with renewed efforts to gain permits for the Pebble Mine, a proposed copper and gold excavation near the headwaters of the Nushagak River. The U.S. Army Corps of Engineers’ considered only two or three years of fish counts in specific locations in proximity to the proposed mine. It states that fish habitat lost to the mine could be recreated elsewhere.

But the new Science study shows that key salmon habitat shifts year to year, and how productive one area is for a short period might not represent its overall value to the fish population or larger ecosystem.

“The overall system is more than just the sum of its parts, and small pieces of habitat can be disproportionately important,” said senior author , a professor at the 91̽��School of Aquatic and Fishery Sciences. “The arrows point to the need to protect or restore at the entire basin scale if we want rivers to continue to function as they should in nature.”

The research team reconstructed the likely geographic locations of nearly 1,400 adult salmon, from their birth in a Nushagak stream until they migrated to the ocean. By looking at each fish’s otolith — which accumulates layers as the animal grows — researchers could tell where the fish lived by matching the chemical signatures imprinted on each “growth ring” of the otolith with the chemical signatures of the water in which they swam.

These chemical signatures come from isotopes of the trace element strontium, found in bedrock. Strontium’s isotopic makeup varies geographically from one tributary to another, particularly in the Nushagak basin, making it easy to tell where and when a fish spent time.

“The otolith is this natural archive that basically provides a transcript of how a fish moved downstream through the river network,” Schindler said. “Essentially, we’re sampling the entire watershed and letting the fish tell us where the habitat conditions were most productive in that year.”

The researchers noticed significant patterns when comparing where fish lived year to year. For example, in 2011 the northwest portion of the watershed in the Upper Nushagak was highly productive for Chinook, meaning more fish were born and gained body mass in that region. But by 2014 and 2015, the population had shifted eastward to utilize resources in the Mulchatna River and its tributaries — several that are downstream of the Pebble deposit.

Similar types of shifts have been documented in a number of land- and water-based animal populations, but this is the first study to show the phenomenon at a watershed-wide scale, the authors said.

“The big thing we show is these types of dynamics are critical for stabilizing biological production through time. When you have a range of habitat available, the total production from the system tends to be more stable, reliable and resilient to environmental change,” Brennan said.

The public comment period for the Pebble Mine draft environmental impact statement recently was extended to June 29 to provide more time for groups to weigh in on the 1,400-page document.

The authors of the new study said they hope it can be used to inform the scientific analysis of the proposed mine’s impact on fish.

“Results like those we’re presenting in this paper hopefully will get people to think about what they stand to lose by starting to develop and eliminate habitat in places like the Nushagak River,” Schindler said. “The Pebble Mine environmental impact statement, which is supposed to be a mature, state-of-the-science assessment of risks, really does a poor job of assessing risks of this specific project.”

Other co-authors are at the University of Utah; and , both former 91̽��graduate students who are now postdoctoral researchers at the University of Michigan and Utah State University, respectively; and at the Alaska Department of Fish and Game.

The study was funded by Bristol Bay Regional Seafood Development Association, the Bristol Bay Science Research Institute and the Arctic-Yukon-Kuskokwim Sustainable Salmon Initiative.

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For more information, contact Brennan at srbrenn@uw.edu and Schindler at deschind@uw.edu.

The largest and oldest Chinook salmon — fish also known as “kings” and prized for their exceptional size — have mostly disappeared along the West Coast.

That’s the main finding of a new 91̽��-led published Feb. 27 in the journal Fish and Fisheries. The researchers analyzed nearly 40 years of data from hatchery and wild Chinook populations from California to Alaska, looking broadly at patterns that emerged over the course of four decades and across thousands of miles of coastline. In general, Chinook salmon populations from Alaska showed the biggest reductions in age and size, with Washington salmon a close second.

“Chinook are known for being the largest Pacific salmon and they are highly valued because they are so large,” said lead author , a research scientist in the UW’s School of Aquatic and Fishery Sciences. “The largest fish are disappearing, and that affects subsistence and recreational fisheries that target these individuals.”

Chinook salmon are born in freshwater rivers and streams, then migrate to the ocean where they spend most of their lives feeding and growing to their spectacular body size. Each population’s lifestyle in the ocean varies, mainly depending on where they can find food. California Chinook salmon tend to stay in the marine waters off the coast, while Oregon and Washington fish often migrate thousands of miles northward along the west coast to the Gulf of Alaska where they feed. Western Alaska populations tend to travel to the Bering Sea.

After one to five years in the ocean, the fish return to their home streams, where they spawn and then die.

Despite these differences in life history, most populations analyzed saw a clear reduction in the average size of the returning fish over the last four decades — up to 10 percent shorter in length, in the most extreme cases.

These broad similarities point to a cause that transcends regional fishing practices, ecosystems, or animal behaviors, the authors said.

“This suggests that there is something about the larger ocean environment that is driving these patterns,” Ohlberger said. “I think fishing is part of the story, but it’s definitely not sufficient to explain all of the patterns we see. Many populations are exploited at lower rates than they were 20 to 30 years ago.”

It used to be common to find Chinook salmon 40 inches or more in length, particularly in the Columbia River or Alaska’s Kenai Peninsula and Copper River regions. The reductions in size could have a long-term impact on the abundance of Chinook salmon, because smaller females carry fewer eggs, so over time the number of fish that hatch and survive to adulthood may decrease.

There are likely many reasons for the changes in size and age, and the researchers say there is no “smoking gun.” Their analysis, however, points to fishing pressure and marine mammal predation as two of the bigger drivers.

Commercial and sport fishing have for years targeted larger Chinook. But fishing pressure has relaxed in the last 30 years due to regulations to promote sustainable fishing rates, while the reductions in Chinook size have been most rapid over the past 15 years. Resident killer whales, which are known Chinook salmon specialists, as well as other marine mammals that feed on salmon are probably contributing to the overall changes, the researchers found.

“We know that resident killer whales have a very strong preference for eating the largest fish, and this selectivity is far greater than fisheries ever were,” said senior author , a 91̽��professor of aquatic and fishery sciences.

While southern resident killer whales that inhabit Puget Sound are in apparent decline, populations of northern resident killer whales, and those that reside in the Gulf of Alaska and along the Aleutian Islands, appear to be growing at extremely fast rates. The paper’s authors propose that these burgeoning northern populations are possibly a critical, but poorly understood, cause of the observed declines in Chinook salmon sizes.

Scientists are still trying to understand the impacts of orcas and other marine mammals on Chinook salmon, and the ways in which their relationships may have ebbed and flowed in the past. It may not be possible, for example, for marine mammals and Chinook salmon populations to be robust at the same time, given their predator-prey relationship.

“When you have predators and prey interacting in a real ecosystem, everything can’t flourish all the time,” Schindler said. “These observations challenge our thinking about what we expect the structure and composition of our ecosystems to be.”

Co-authors are Eric Ward of NOAA’s Northwest Fisheries Science Center and Bert Lewis of the Alaska Department of Fish and Game.

This study was funded by the Pacific States Marine Fisheries Commission.

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For more information, contact Ohlberger at janohl@uw.edu and Schindler at deschind@uw.edu.

One of Alaska’s most abundant freshwater fish species is altering its breeding patterns in response to climate change. This could impact the ecology of northern lakes, which already acutely feel the effects of a changing climate.

That’s the main finding of a recent 91̽�� published in Global Change Biology that analyzed reproductive patterns of fish over half a century in Alaska’s Bristol Bay region. The data show that stickleback breed earlier and more often each season in response to earlier spring ice breakup and longer ice-free summers.

While several papers have speculated that conditions brought on by a warming climate may allow animals to breed more often in a single year, this has only been empirically shown in insects. This study is the first to document multiple breeding cycles for fish in a single season due to climate change, said lead author , a postdoctoral researcher in the UW’s .

“The exciting thing about this paper is that it shows, for the first time, the emergence of multiple breeding in a vertebrate as a response to climate change,” Hovel said. “Climate change literature features many predictions and vulnerability assessments, but we don’t have many opportunities to actually observe species’ responses over time, as this is very data-intensive. Our ability to detect multiple breeding in fish is attributed to our comprehensive and high-quality long-term dataset.”

The data were collected from 1963 to 2015 in Alaska’s , home to one of the UW’s research stations. The research program has for decades recorded the abundance of juvenile sockeye salmon and other fish that live in the region’s freshwater lakes. For 52 years, fish were captured in nets along the lakeshore at 10 different sites every seven days between June and September. All fish were identified and measured.

While the program’s monitoring was designed to track the commercially important sockeye salmon population, scientists also meticulously recorded every other fish present, including three-spine stickleback. Stickleback represent almost half of the fish found in Lake Aleknagik, with juvenile sockeye salmon nearly matching that percentage. Three-spine stickleback make up a large percentage of the fish communities in many northern lakes, so these findings could be relevant throughout the region, Hovel said.

“Alaska is warming about twice as rapidly as most of the rest of the planet,” she said. “These fish are adapted to survive in relatively cold environments with limited productive seasons. The responses to rapid warming that we see in lakes, like early spring ice breakup, are releasing some of these constraints.”

Stickleback are born near the shore, then move to the middle of the lake to feed on zooplankton. Adults return to the shore in the summer to spawn; males will build the nest and attract a female, who then lays the eggs. Males guard the nest until the fish hatch, usually after about two weeks.

By analyzing decades of data showing fish sizes throughout each summer, Hovel and collaborators could determine roughly when certain fish were born ― a larger fish captured in August was indicative of an early season brood, while a smaller fish captured on the same day likely came from a brood that hatched later in the summer.

Using these data and additional environmental data, researchers found that three-spine stickleback spawned earlier in years when ice breakup occurred earlier, and in some years, the fish produced more than one brood. Given the short summers in Alaska, most stickleback have time and stamina for only one brood, but increasingly they are rearing two broods a summer as climate change ushers in earlier springs.

These factors could have wider ecological effects, as three-spine stickleback are a dominant fish species in many northern lakes. This is particularly true for sticklebacks’ primary competitor in many coastal lakes in Alaska: juvenile sockeye salmon. The two species share the same habitats in lakes and generally eat the same things.

“If stickleback are increasing in abundance because of their modified reproduction strategy, this can have ecosystem implications for the productivity of species we commercially care about, like sockeye salmon,” Hovel said.

Researchers don’t yet know if breeding more often and earlier in life is beneficial for three-spine stickleback, but it does appear that over the long term, the fish will likely increase their abundance.

“We don’t know exactly what this means for demographics of this species,” Hovel explained. “It could also mean that fish are living shorter lives because there’s a higher physiological cost to breeding more than once. In the lower-latitude extent of their range, fish mature earlier and die earlier.”

Other co-authors are , a 91̽��professor of aquatic and fishery sciences; and at University of California, Berkeley, who earned her doctorate at the 91̽��and worked with the Alaska Salmon Program.

Data collection for this study was funded by the Pacific Salmon Seafood Industry, the Gordon and Betty Moore Foundation, the Alaska Department of Fish and Game and the National Science Foundation. Hovel’s analysis was funded by the H. Mason Keeler and Richard and Lois Worthington endowed professorships.

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For more information, contact Hovel at rhovel@uw.edu or 206-616-5761.

These , published Jan. 16 in Nature Communications, draw upon 34 years of data collected in more than 100 fishing communities in Alaska that depend on fishing for livelihoods, cultural traditions and daily subsistence. The 91̽�� researchers found that communities that fished for many different species and had the ability to shift what they harvested, and when, were more resilient to unpredictable downturns in fish abundance and market prices than communities that put all their effort into only a few fisheries.

“This study is about starting the conversation about how communities can buffer themselves against unpredictable ecosystem changes in the future,” said lead author , a doctoral student in the UW’s School of Aquatic and Fishery Sciences. “There is no reason why any community in the world that depends on renewable resources could not benefit from this approach.”

In their analysis, the researchers used common financial principles to illustrate how fishing communities can buffer against market and ecosystem shifts. Maintaining a diverse portfolio of fishing permits, for example, ensures that a community can switch to halibut or Dungeness crab if salmon take a turn for the worse. Just like with financial stocks, each fishery might not deliver at the same time, but that diversity allows for stability in the long run.

“Human systems can collapse if they have no ability to roll with the punches and adapt when ecosystems re-express themselves,” said co-author , a 91̽��professor of aquatic and fishery sciences. “This analysis shows that the communities that did not suffer from oceanic regime shifts were those that could adapt to changes in the quantity and composition of natural resources.”

The researchers looked specifically at the average fishing revenue in 106 Alaskan communities for 10 years before and after 1989, a year when the North Pacific Ocean experienced a significant shift in productivity and abrupt changes in the composition of marine food webs, while at the same time the global price for salmon dropped because of competition from farm-raised fish.

Commercial fishing in Alaska provides $1.3 billion in annual income from harvest alone, and in some remote areas fishing is the only major industry.

Many Alaskan communities lost more than half of their revenue following 1989. However, the researchers found that communities with the highest level of diversity in what they fished for saw little or no change in revenue. Specifically, communities that had high diversity were able to shift to different fisheries after 1989, and some even increased their revenue streams by leveraging new and emerging fish markets.

“We found that well-diversified communities also had higher turnover, or the ability to go out and fish for species that are more abundant while relying less on those that declined,” Cline said. “If you are diversified, it’s just a matter of focusing on fisheries that are more abundant or more valuable, and if you’re not diversified, that means adapting your portfolio by selling what you had and buying something new.”

The authors recognize this can be difficult for individual fishermen ― fishing permits are expensive and can be hard to obtain. When dispersed across the community level, however, individuals could still specialize, but differently from their neighbor. For example, one subset could fish for pink salmon, while another tackles halibut or Dungeness crab. Revenues from these efforts are felt throughout the community.

Additionally, this approach promotes a powerful shared identity, the authors explain.

“There’s intrinsic value in the identity of being a fishing community,” Schindler said. “That sense of community identity is basically reinforced by the fact that the community is adapting to the ecosystem, which is always changing.”

The rich dataset used in this analysis, provided by the Alaska Commercial Fisheries Entry Commission, was invaluable in allowing the researchers to test concepts of diversification and turnover ― switching to catch more abundant fish ― which have been put forth in other papers as ways of managing human interactions with natural resources.

These principles could be applied to fisheries around the world, and many small fishing communities already diversify naturally, the authors explained. Traditional science tends to emphasize gathering data to make better predictions of how natural resources will fare, but perhaps that isn’t the best approach when managing resources in a highly variable and unpredictable environment, they argue.

“With ongoing climate change, population growth and ocean acidification, the question is, what’s the future going to look like? We should expect the unexpected,” Schindler said. “Then the question becomes, what can we do to develop resilient communities for what is guaranteed to be an unexpected new future?”

“While 40 years ago most fishermen were generalists, and switched between fish stocks as they fluctuated, the efforts to reduce overall fishing effort has generally forced fishermen to specialize in a small number of fisheries, said co-author , a 91̽��professor in aquatic and fishery sciences. “We need to explore ways to allow flexibility while still restraining the total catch.”

This work was funded by the National Science Foundation.

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For more information, contact Cline at tjcline@uw.edu and Schindler at deschind@uw.edu or 206-616-6724.

Grant number: CNH #1114918

The 91̽�� and Mt. Baker Ski Area are collaborating this month to present “.” The free 20-minute talks by 91̽��faculty members will take place three consecutive Saturdays at 3:30 p.m. in the ski area’s White Salmon Lodge.

The first presentation on Jan. 9, will be given by , 91̽��professor of atmospheric sciences, who will talk about “The Future of Ice – Far and Near.” Her talk is a fitting kickoff for the series, which is an outreach effort by the UW’s interdisciplinary initiative.

Next will be , professor of aquatic and fishery sciences, who will speak Jan. 16 on “Climate and the Future of Salmon in the Pacific Northwest.” Schindler’s research looks at how factors such as climate change and urbanization affect salmon populations in Alaska and the Northwest.

The final presentation, on Jan. 23, will be by , researcher with the UW’s Joint Institute for the Study of the Atmosphere and Ocean and Washington’s state climatologist, who will speak on “El Niño, the Blob and Climate Change: What it Means for Our Neck of the Woods.”

The series gets its title from the recent agreement to try and , signed in December at a meeting of world leaders in Paris.

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For more information, contact series coordinator and 91̽��Future of Ice postdoctoral researcher Sarah Myhre at semyhre@uw.edu.

This bone, called an , accumulates layers as a fish grows, similar to trees. These “growth rings” are produced throughout a salmon’s life. Scientists can tell where the fish lived by matching the chemical signatures of the otolith with the chemical signatures of the water in which they swim, according to a published May 15 in the online, open-access journal .

“Each fish has this little recorder, and we can reveal the whole life history of the fish from the perspective of the otolith. Each growth ring is a direct reflection of the environment the fish was swimming in at the time it was formed,” said lead author Sean Brennan, who completed the study as a doctoral student at the University of Alaska Fairbanks. He is now a postdoctoral researcher in the 91̽��’s .

This chemical signature comes from isotopes of the trace element , found in bedrock. Strontium’s chemical makeup varies geographically. As rushing water weathers the rocks, the element is dissolved and released into the water. The dissolved strontium ions get picked up by fish, either through the gills or gut lining, then are deposited onto the otolith.

As strontium makes its way from rocks into the otoliths of fish swimming in the rivers, its chemical signature does not change, and so it serves as a robust tag that can tie each fish as being in a specific location in the river at a specific time.

“This particular element and its isotopes are very strongly related to geography,” said Matthew Wooller, director of the Alaska Stable Isotope Facility at University of Alaska Fairbanks and a co-author of the paper. “It is a really good marker for where animals have been and whether they move around in their environment.”

This process relies on a river system that has been mapped extensively for its strontium isotope variation. In general, watersheds that are diverse in the types and ages of rocks will also have a lot of variation in strontium isotope signatures – and thus are good candidates for using this technique, Brennan said.

“Alaska is a mosaic of geologic heterogeneity,” he added. “As long as you can look at a geologic map and see rocks that are really different, that’s a good potential area.”

The Bristol Bay region in Alaska produces some of the last remaining wild salmon runs in the world. The area is perhaps best known for its sockeye salmon commercial fishery, but Chinook salmon, particularly those in the where this study took place, supply important subsistence and sport fisheries for the region. The Nushagak Chinook salmon are also the third biggest run in Western Alaska, ranking it as one of the largest worldwide.

About 200,000 Chinook make their way each summer from the ocean to spawn in the river’s upper tributaries and streams. When their eggs hatch in the spring, young Chinook salmon spend a whole year in the river, feeding and growing before migrating to the Bering Sea and the Pacific Ocean.

Scientists need a way to determine the birth streams of adult Chinook when they are caught in coastal fisheries. Once they have that information, they can begin to understand how freshwater habitat, the movement of fish and environmental factors can affect fish survival. Alaska’s Chinook salmon populations have declined dramatically in the past decade, and scientists are still trying to determine why.

“This is science responding to a societal issue and need,” said co-author , U.S. Geological Survey ecologist and chief of water and interdisciplinary studies at the USGS Alaska Science Center in Anchorage. “Using this approach, we will be able to map salmon productivity and determine how freshwater habitats influence the ultimate number of salmon. With declines in Chinook salmon in Western Alaska, fishery and land-use managers need better information about freshwater habitats to guide conservation.”

Using data collected from adult salmon in 2011, the researchers not only determined which parts of the river produced the most fish but also found that the majority of Chinook salmon in the Nushagak watershed stayed in the same place for their entire first year before they migrated to the ocean. About 20 percent left their birthplace for short forays in the river’s lower main stem before swimming to the ocean.

Brennan now works with at the UW, where they will expand this work to include sockeye salmon in the same river. They will collect three years of Chinook data and two years of sockeye by end of the project, which will help determine whether birth and life history patterns in Alaskan rivers vary across years, or remain consistent.

The techniques used in Brennan’s study can also help scientists understand the behavior of other animal populations. Strontium also accumulates in things like bird feathers and teeth and also survives even after being fossilized. This allows researchers to study the movements of a wide range of animals including seals, whales, bison, ancient human populations and even dinosaurs.

Other co-authors are Diego Fernandez and Thure Cerling at the University of Utah, where all of the analyses for this research were conducted, and Megan McPhee at the University of Alaska Fairbanks.

This research was funded by Alaska Sea Grant and the U.S. Geological Survey National Institute of Water Resources program.

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For more information, contact Brennan at srbrenn@uw.edu or 801-633-7906; Zimmerman at czimmerman@usgs.gov or 907-786-7071; Cerling at thure.cerling@utah.edu or 801-581-5558; and Wooller at mjwooller@alaska.edu or 907-474-6738.

Grant numbers: R/100-02 (Alaska Sea Grant); 2012AK108B (U.S. Geological Society)

It’s no different in the natural world. The Earth is warming, fish stocks and species counts fluctuate and we’re experiencing more extreme weather. Conservation managers need to act quickly and make decisions about how to address these issues – even though questions remain.

That’s the argument of two 91̽�� researchers whose perspectives article appears Feb. 27 in .

“Modern science is producing lots of new knowledge, but we question whether that knowledge is going to accumulate fast enough to be useful as systems change rapidly,” said , a co-author and 91̽��professor of aquatic and fishery sciences. “We have to learn how to manage our ecosystems and natural resources in a reality where uncertainties dominate. That often means we have to make tough decisions with lousy knowledge.”

The usual path for those tasked with environmental conservation is to study certain aspects of an ecosystem, then try to predict what will happen down the road. Many scientists and funding agencies say that better understanding of a particular system will produce more accurate predictions that lead to more informed decisions.

But Schindler and co-author , a 91̽��professor of aquatic and fishery sciences, argue that it’s impossible to understand a changing, natural system in great detail, and that important policy moves shouldn’t hinge on the ability to have all the facts. Instead, managers must learn to make decisions based on an uncertain future.

“We have to learn to manage what we’ll never fully understand,” Schindler said.

Managers must develop robust policies that would remain effective no matter how the future unravels.

“Rocket scientists have it easy: Natural ecosystems are much more complex than rockets and we must identify management policies that are robust to the uncertainty in how the natural systems will respond,” said Hilborn.

The authors offer several suggestions to achieve this:

• Create policies that have legs: When developing a policy to manage fisheries or allocate water distribution in agriculture, for example, make it flexible so it can continue to effectively manage the resource, no matter how it changes in the future.
• Support policies that encourage ecosystem diversity: Opt for plans that encourage organism and habitat diversity, because casting a larger net will let the policy be most responsive no matter what happens in the future.
• Invest more in monitoring: Don’t just collect data, but actively analyze the data, drawing connections to the past and assessing what that relationship might mean for the future. Do more field-based monitoring and less predictive modeling.
• Expect a future that’s different from the past: Move away from a “better safe than sorry” approach to management and assume the ecosystem will shift in unexpected ways. Design policies that can adapt based on how the ecosystem changes.

Schindler and Hilborn say these principles can guide management of any natural or renewable resource, including agriculture, fisheries and forestry, to name a few. They argue that sustainability is about achieving human connections with properly functioning ecosystems, and that it’s important to set up policies that keep people engaged with the natural world.

These recommendations likely won’t surprise everyone in resource management, and the authors acknowledge many among them already are working in this way, or striving to do so. It could, however, be more difficult for scientists and funding agencies that still think “mechanistic science is what produces the knowledge needed to manage the world,” Schindler said.

“We are not trying to devalue the science, but it is critical to have an honest, frank discussion among all the players about what approaches we are taking to really contribute to sustainability,” he added.

The research was funded by the National Science Foundation and the Harriet Bullitt Professorship at the UW.

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For more information, contact Schindler at deschind@uw.edu or 206-616-6724 and Hilborn at rayh@uw.edu. Hilborn is currently in Australia, so email is best.