To understand how Puget Sound has changed, we first must understand how it used to be. Unlike most major estuaries in the U.S. — and despite the abundance of world-class oceanographic institutions in the area — long-term monitoring of Puget Sound fish populations did not exist until 1990. Filling in this missing information is essential to establishing a baseline that would provide context for the current status of the marine ecosystem, and could guide policymakers in setting more realistic ecosystem-based management recovery targets.

Researchers from the 91̽�� School of Aquatic and Fishery Sciences, 91̽��Puget Sound Institute, NOAA’s Northwest Fisheries Science Center and Washington Department of Fish and Wildlife have discovered an unconventional way to help fill in these gaps in data: using old vessel logbooks.

The crews of the 91̽��’s then School of Fisheries’ research vessels R/V Oncorhynchus (1947 to 1955) and R/V Commando (1955 to 1980), both of which were skippered by , took notes on all of the fish tows conducted under their watch. With funding from Washington Sea Grant, the researchers combed through more than 1,000 of these logbook entries to analyze the information regarding the groundfish species caught in each tow, including when and where the fish were caught. Then, the researchers analyzed historical logbook data from 1948 to 1977 and contemporary monitoring data to reveal longer-term trends in the local groundfish populations. The research was published in last month.

Although there were changes throughout the periods analyzed, the researchers did not find that groundfish populations today in Puget Sound look fundamentally different from the historical populations.

“We see the same types of fluctuations in the historical data as in the contemporary data,” said , professor at the School of Aquatic and Fishery Sciences and the study’s lead author. “This suggests that boom and bust populations are natural, and speaks to the importance of having a long time view to establishing a baseline.”

However, some trends did stand out, Essington explained. For example, Pacific cod used to be very common but is rare today, and the abundance of Pacific spiny dogfish has decreased.

The fact that the researchers were able to fill in any of the historical gaps was really a matter of luck: the right people had maintained the research vessels at the right time.

“They were remarkable, the records,” Essington said. “They not only noted the species and size, but also detailed descriptions of the locations. It was amazing what we could reconstruct.”

was a graduate student at the School of Fisheries from 1957 to 1960, during which he ventured out on the Commando along with Oswold and his advisor, Allan DeLacy, to collect data for his research on Puget Sound rockfish. He remembers once being chastised for filling out the logbook incorrectly.

“I had misspelled one of the scientific names — that was the only time I remember that DeLacy got mad at me,” Hitz said. “He said that the logbooks had to be correct.”

This level of precision made Essington’s work possible decades later. For Hitz, the logbooks also became a rich repository of memories.

“When I was going through the logs of the Commando, I found an entry that I had written on May 3, 1960,” he wrote in a 2015 . “It was for trip #6017 and it brought back a wave of memories, since that was my first encounter with the open waters of the Pacific Ocean. At the time I was being considered for a job with the Exploratory group which worked the outside waters from Mexico to the Bering Sea. The first thing that came to my mind was, would I become seasick once I was outside? If so, would three years of graduate school be wasted? There was no class about seasickness given at the [School of Fisheries], but there was talk.”

Although the researchers analyzed logbooks up until 1977, Essington explained that they became considerably less useful after 1973. As Hitz recalls, this was around the time the school began to place more emphasis on chartering the Commando for outside research, rather than using it for students’ education and research.

“I assume the logbooks became less important when the boat was being chartered,” Hitz said.

Essington described the project methods as “half detective work and half computer work.” The detective work involved the researchers carefully perusing the old logbooks while wearing N-95 masks to protect themselves from the mildew and dust (prior to COVID-19). The computer work involved analyzing how the catch rates of 15 groundfish species differed between the historical and contemporary datasets, to understand how the general groundfish populations differed between the two periods.

Given that the details within the logbooks petered out, and then stopped altogether once the Commando was retired, the researchers were forced to leave out an important period in their analysis.

“There was a 17-year gap between the captain’s books and current monitoring, and no amount of scrappiness could fill this in,” Essington said.

The years between the two datasets — the bulk of the 1970s and 80s — also happened to coincide with extensive environmental change in Puget Sound, including the implementation of regulations to address pollution and protect endangered species. A few changes particularly impacted groundfish: For example, the 1974 Boldt decision resulted in increased non-tribal recreational groundfish fishing. Subsequently, the introduction of bag limits, marine protected areas and species-take prohibitions in the late 1980s and early 1990s reduced the intensity of recreational groundfish fishing.

in June 2020, groundfish were added as a food web indicator species for the Puget Sound Partnership’s , which has guided policy since 2010. This research could help shed light on what to look for as healthy for this vital sign, the authors said.

“It might be better to think about baselines in the dynamic sense,” Essington said. “To focus on acceptable ranges of fluctuation, rather than a precise number.”

Other co-authors are and of the Northwest Fisheries Sciences Center; of Puget Sound Institute at 91̽��Tacoma; , an independent consultant who previously worked at the 91̽��School of Aquatic and Fishery Sciences; and of Washington Department of Fish and Wildlife.

This study was funded by Washington Sea Grant, The Seadoc Society and the Lowell Wakefield Endowment.

For more information, contact Essington at essing@uw.edu.

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 .

Anchovies, herring, sardines and other forage fish play an essential role in the food web as prey for seabirds, marine mammals and larger fish like salmon. When ground into fishmeal and oil, they are also a key food source for farmed seafood and land-based livestock such as pigs and poultry.

As seafood consumption outpaces the growth of other food sectors and continues to grow worldwide, farmed seafood — also called aquaculture — has increased rapidly to meet consumer demand. That means aquatic farming now puts the most pressure on the smaller forage fish harvested to feed their larger farmed counterparts such as salmon, carp and tilapia.

A new appearing online June 14 in Nature Sustainability shows that if current aquaculture and agriculture practices remain unchanged into the future, wild forage fish populations likely will be overextended by the year 2050, and possibly sooner — even if all stocks were fished sustainably. But the team, which includes researchers from the University of California, Santa Barbara, and the 91̽��, found that making sensible changes in aquaculture and agriculture production would avoid reaching that threshold.

“Aquaculture has a lot of potential to keep feeding the future planet, but we do probably need to make some changes for sustainability,” said co-author , a 91̽��professor of aquatic and fishery sciences. “We are in a position to start thinking about different scenarios and how we want to invest in technological advances to shape how the aquaculture field is run.”

The aquaculture industry is growing by about 6 percent each year, currently producing 75 million metric tons of seafood worldwide. The researchers believe this is the first attempt to measure the projected demands on forage fish for aquaculture and livestock, while considering what measures could be taken to maintain healthy, stable wild fish populations across multiple sectors.

Anchovies, sardines and other palm-sized, schooling fish are caught in the ocean and processed into fishmeal and oil to feed to other fishes and crustaceans that are raised in aquatic farms around the world. But, livestock animals still eat them too, and have been since at least the 1960s. In aquaculture, carps are some of the biggest forage fish customers, even though they are not as dependent on them to grow as are salmon and shrimp.

“Aquaculture is the fastest-growing food sector in the world and has already surpassed beef, as well as wild fisheries seafood production. There’s a lot of concern about forage fish use and whether or not what we’re doing — feeding fish to fish — is sustainable,” said lead author , a postdoctoral researcher at the National Center for Ecological Analysis and Synthesis at UC Santa Barbara. Froehlich completed her doctorate at the 91̽��in 2015.

The study authors used computer simulations to examine five different ways the aquaculture, fisheries and agricultural sectors could change to take the strain off forage fish. They found that eliminating their use in food for farmed carp and other freshwater fishes produced the most savings of forage fish over time, compared with a business-as-usual model. Those fish do not have to eat other fish in the wild to survive, but producers feed them fishmeal and oil simply because it helps them grow better and faster.

Also beneficial was a scenario that removed forage fish from feed for pigs and poultry — a trend that has been occurring over the last few decades already. Additionally, their projections indicated that salvaging the unused parts from farmed and wild fish in China and processing these trimmings into fishmeal and oil would help sustainably stretch, but not completely solve, the protein content of forage fish.

When modeling the various scenarios, the researchers looked at the biggest consumers of forage fish, while also considering the practicality of removing this food source from the diets of various species. For example, cutting forage fish from farmed salmon and tuna diets is harder because these fish hunt other fish in the wild and rely on more animal protein to survive. Taking it out of carp and pig diets, though, is less detrimental to the growth of these animals.

The big unknown, the authors said, is how much fish humans will eat in the future if diets increasingly favor seafood over other meat — what is termed a pescetarian diet. This upward trend would require an even larger aquaculture market, which will in turn demand more forage fish for use as feed.

“There are very clear steps that can be taken to mitigate the pressure from aquaculture, but if the whole world ate a little more fish, then that degrades the savings you get from these mitigating measures at the levels we assessed,” Froehlich said. “These unknowns really emphasize how important alternative feed sources are for the long-term sustainability of aquaculture.”

Growing and harvesting algae, insects and seaweed are all options being tested and considered as alternative feed sources for aquaculture and livestock animals, reducing the strain on forage fish. Crops such as soy are among the largest alternatives right now for both livestock and farmed seafood.

Other co-authors are Nis Sand Jacobsen of NOAA, who recently worked as a 91̽��postdoctoral researcher; and Tyler Clavelle and Benjamin Halpern of UC Santa Barbara.

This study was funded by the Science for Nature and People Partnership, and the authors acknowledge support from the Villum Foundation and the Waitt Foundation.

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For more information, contact Froehlich at froehlich@nceas.ucsb.edu and Essington at essing@uw.edu.

To successfully manage fisheries, factors in the environment that affect fish — like food sources, predators and habitat — should be considered as part of a holistic management plan.

That approach is gaining traction in fisheries management, but there has been no broad-scale evaluation of whether considering these ecosystem factors makes any economic sense for the commercial fishing industry. In these often profitable and competitive markets, that question has lacked the evidence to rule one way or another.

A team of ecologists and economists has addressed that question in the first study to test whether real-life ecological interactions produce economic benefits for the fishing industry. The last week in the Proceedings of the National Academy of Sciences.

“Going into this, I shared the belief that because we know species are connected, ignoring that connection is potentially putting ecosystems in harm. What we really found was a much more nuanced benefit,” said lead author , a 91̽�� professor of aquatic and fishery sciences. “Rather than enhancing economic benefits, the holistic approaches to natural resource management are better viewed as a way to more equitably distribute risk and reward across different users.”

The researchers found that economic benefits were minor when ecological interactions were factored into the equation. Instead, this ecosystem-based approach offers other benefits to the fishing industry — namely, a simple set of rules to avoid scenarios that could cause a worst-case outcome for fishes and their surrounding environments.

Most U.S. fisheries are managed by looking at the biology of the targeted fish species. Managers consider what the species’ expected abundance is year to year and make decisions about how many can be caught each season. That process, however, doesn’t account for ecosystem factors such as predators, habitat or temperature that also can influence a species’ abundance. This can lead to an incorrect estimate of the number of fish that can be caught sustainably.

To test whether a holistic approach helps or hurts the industry from an economic perspective, the researchers looked at an actual predator-prey relationship between two fisheries, cod and herring. Separately, both fisheries are among the largest and most profitable in the world.

The researchers created a model to represent the interactions of the two fisheries, then used the model to look at the likely economic outcomes of 16 scenarios. For each scenario, cod and herring began at either high or low abundance, and the linkage between the two species varied from no interaction, to one species eating the other, or the other’s eggs. The researchers then calculated the fishing strategy that would lead to the maximum economic value under each scenario.

A final step was to ask what would happen if managers took action based on inaccurate information about the relationship between the species. This was important to consider because it is common to have uncertainty about ecosystem relationships.

“What we were trying to capture was the idea that we often have to make decisions about natural resources in complex linkage systems where we don’t know the nature or magnitude of the linkages,” Essington said.

Their analysis found that, in most of the scenarios, ecosystem information (the predator-prey interactions) made very little difference from an economic standpoint. When cod abundance was low, however, the potential for economic losses was substantial, particularly for the cod fishery.

For example, in scenarios with low cod and high herring populations, the value of the two fisheries combined could decline by as much as 15 percent. This impact fell mainly on the cod industry, which shows that some fishing groups are more vulnerable than others to economic losses.

Overall, ecosystem factors did not have a large effect on the profitability of fisheries, but they did offer helpful information about avoiding worst-case scenarios, and bolstered the argument for maintaining fisheries in “safe zones” — scenarios where there are low risks of major economic losses from something going badly in the ecosystem. The findings provide a framework for managers to identify the safe zones specific to each fishery.

“Most importantly, this study shows that one doesn’t need to know all of the ecological intricacies to have good ecological and economic outcomes,” Essington said. “It’s about simplicity, and the idea that we don’t have to have complex management systems to deal with complex ecosystems.”

Other co-authors are and of the University of California, Davis.

This study was funded by the Pew Fellowship in Marine Conservation.

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For more information, contact Essington at essing@uw.edu or 206-616-3698.

A new by 91̽�� scientists has found that, for dozens of fish populations around the globe, old fish are greatly depleted — mainly because of fishing pressure. The paper, published online Sept. 14 in Current Biology, is the first to report that old fish are missing in many populations around the world.

“From our perspective, having a broad age structure provides more chances at getting that right combination of when and where to reproduce,” said lead author , a 91̽��postdoctoral researcher at the School of Aquatic and Fishery Sciences and the Joint Institute for the Study of the Atmosphere and Ocean.

In forestry, a tree farm with only 20-year-old trees may be healthy and productive, but the loss of old-growth trees should not go unnoticed. The giant trees have unique traits that support a number of animal and plant species and make for a diverse, robust ecosystem. In a similar sense, the same is true for old fish.

“More age complexity among species can contribute to the overall stability of a community,” Barnett said. “If you trim away that diversity, you’re probably reducing the marine food web’s ability to buffer against change.”

The designation of an “old fish” varies from species to species, depending on life history. Some types of rockfish might live to 200 years, while few herring live past age 10.

After female fish release eggs, many factors must align for a healthy brood to hatch and grow to adult size. Because the marine environment is so variable, species might go a whole decade between successful broods. Older fish in a population have more years to produce eggs, increasing the chance for success over time.

“In the marine world, the success rate of producing new baby fish is extremely variable,” said co-author , a 91̽��associate professor of aquatic and fishery sciences. “I think of old fish as an insurance policy — they get you through those periods of bad reproduction by consistently producing eggs.”

In addition to having more opportunities to reproduce, older fish also behave differently than younger fish. As they age, some fish change what they eat and where they live in the ocean. They also take on different roles in the marine food web, sometimes becoming a more dominant predator as they get older, and bigger.

When you take old fish out of the mix, the diversity and stability of an ecosystem can suffer, the authors explain.

“Big fish are in a lot of ways different from smaller fish,” said co-author , a 91̽��professor of aquatic and fishery sciences. “Having that diversity acts as a hedge against risk and helps stabilize the system a bit.”

The researchers looked at model output gathered from commercial and recreational fisheries and scientific observations that describe the status of fish populations over the years. In their analysis of 63 populations living in five ocean regions worldwide, they found that the proportion of fish in the oldest age classes has declined significantly in 79 to 97 percent of populations, compared with historical fishing trends or unfished figures, respectively. The magnitude of decline was greater than 90 percent in 32 to 41 percent of the groups.

This is mainly due to fishing pressure, the researchers say. In general, the longer a fish lives, the more encounters it has with fishing gear, and the greater the likelihood it will be caught. However, some environmental factors like disease and pollution might also contribute to the loss of old fish.

These findings could inform fisheries management, which often sets limitations based on the total weight of fish caught over a season without considering factors such as the size or age of a fish. The authors suggest fishing methods to protect young and old fish by prohibiting the harvest of fish below and above a specific size range. Other solutions include closing certain areas to fishing permanently, or rotating areas where fishing can take place each year to let fish grow older and bigger — similar to agricultural crop rotations that allow the soil to recover between planting cycles.

The paper’s other co-author is R. Anthony Ranasinghe of Virginia Polytechnic Institute and State University, who completed data analysis for the paper with the aid of a NOAA Hollings Undergraduate Scholarship.

The work was directly funded by the UW’s Joint Institute for the Study of the Atmosphere and Ocean under a NOAA cooperative agreement, with additional funding from the Richard C. and Lois M. Worthington Endowed Professor in Fisheries Management.

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For more information, contact Barnett at lewisab@uw.edu; Branch at tbranch@uw.edu; and Essington at essing@uw.edu or 206-616-3698.

Dungeness crabs, for example, will likely suffer as their food sources decline. Dungeness crab fisheries valued at about $220 million annually may face a strong downturn over the next 50 years, according to the published Jan. 12 in the journal Global Change Biology. But pteropods and copepods, tiny marine organisms with shells that are vulnerable to acidification, will likely experience only a slight overall decline because they are prolific enough to offset much of the impact, the study found.

Marine mammals and seabirds are less likely to be affected by ocean acidification, the study found.

“What stands out is that some groups you’d expect to do poorly don’t necessarily do so badly – that’s probably the most important takeaway here,” said , lead author of the study who pursued the research as a postdoctoral researcher at the 91̽�� and NOAA Fisheries’ Northwest Fisheries Science Center. “This is a testament in part to the system’s resilience to these projected impacts. That’s sort of the silver lining of what we found.”

While previous studies have examined the vulnerability of particular species to acidification in laboratories, this is among the first to model the effects across an entire ecosystem and estimate the impacts on commercial fisheries.

“The real challenge is to go from experiments on what happens to individual animals in the lab over a matter of weeks, to try to capture the effects on the whole population and understand how vulnerable it really is,” said , a research scientist at NOAA Fisheries’ Northwest Fisheries Science Center in Seattle.

The research used sophisticated models of the California Current ecosystem off the Pacific Coast to assess the impacts of a projected 0.2 unit decline in the pH of seawater in the next 50 years, which equates to a 55 percent increase in acidity. The California Current is considered especially vulnerable to acidification because the upwelling of deep, nutrient-rich water low in pH already influences the West Coast through certain parts of the year.

The ocean absorbs about one-third of carbon dioxide released into the atmosphere from the burning of fossil fuels, which has led to a 0.1 unit drop in pH since the mid-1700s.

The research built on an earlier effort by NOAA scientists and that quantified the sensitivity of various species to acidification, as originally reported in 393 separate papers. In a novel approach, Busch and McElhany weighed the evidence for each species based on its reported sensitivity in the laboratory, relevance to the California Current and agreement between studies.

This synthesis by Busch and McElhany identified 10 groups of species with highest vulnerability to acidification. Marshall and colleagues incorporated this into the ecosystem model to examine how acidification will play out in nature. The study particularly examined the effects on commercially important species including Dungeness crab; groundfish such as rockfish, sole and hake; and coastal pelagic fish such as sardines and anchovy over the period from 2013 to 2063.

“This was basically a vulnerability assessment to sharpen our view of where the effects are likely to be the greatest and what we should be most concerned about in terms of how the system will respond,” said , a 91̽��professor of aquatic and fishery sciences and a co-author of the research.

The study provides a foundation for further research into the most affected species, he said.

Although earlier studies have shown that Dungeness crab larvae is vulnerable to acidification, the assessment found that the species declined largely in response to declines in its prey – including bivalves such as clams and other bottom-dwelling invertebrate species.

Since Dungeness crab is one of the most valuable fisheries on the West Coast, its decline would have some of the most severe economic effects, according to the research. Groundfish such as petrale sole, Dover sole and deep-dwelling rockfish are also expected to decline due to acidification, according to the assessment. However, fisheries for those species are much less valuable so the economic impact would not be as large.

Coastal pelagic fish were only slightly affected.

“Dungeness crab is a bigger economic story than groundfish,” Kaplan said. “There are winners and losers, but the magnitude of the impact depends on how important the species is economically.”

The research was funded by the NOAA Ocean Acidification Program and the National Centers for Coastal Ocean Science. Marshall was supported by a National Research Council fellowship.

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For more information, contact Marshall at kmarsh2@uw.edu and Kaplan at isaac.kaplan@noaa.gov 206-302-2446.

This piece was adapted from a Northwest Fisheries Science Center .

, a 91̽��professor of aquatic and fishery sciences, and , a 91̽��professor of practice and lead scientist at The Nature Conservancy, head a convened by the to guide managers on implementing ecosystem-based fisheries management. After two years of regional workshops, meetings and literature reviews, the group just released its recommendations .

Essington and Levin will take part in related briefings Nov. 16 on Capitol Hill and to the White House’s Council for Environmental Quality.

“This report is a blueprint for a ‘next generation’ of fisheries ecosystem plans,” said Essington, who chairs the group. “The taskforce envisioned a more action-oriented version of an existing mechanism in the U.S. system.”

U.S. fisheries management is organized around fishery management plans, traditionally focused on a single species or a group of related species. The ecosystem approach builds on single-species management by accounting for the relationships among all players — marine organisms, humans and the environment — in a holistic, integrated way.

Some regional fishery councils have adopted these plans, but they differ substantially, and there is no common standard for what they should contain. The report includes a flexible, five-step process to help councils and other management bodies formulate strong ecosystem-based plans.

The 12 additional taskforce members are social and natural scientists from universities across the country. The Lenfest Ocean Program began in 2004 and is managed by The Pew Charitable Trusts.