Alaskan waters are a critical fishery for salmon. Complex marine food webs underlie and sustain this fishery, and scientists want to know how climate change is reshaping them. But finding samples from the past isn鈥檛 easy.

鈥淲e have to really open our minds and get creative about what can act as an ecological data source,鈥� said , currently a postdoctoral researcher at the Peabody Museum of Natural History at Yale University.

As a doctoral student at the 天美影视传媒 in Seattle, Mastick investigated Alaskan marine food webs using a decidedly unorthodox source: old cans of salmon. The cans contained fillets from four salmon species, all caught over a 42-year period in the Gulf of Alaska and Bristol Bay. Mastick and her colleagues dissected the preserved fillets from 178 cans and counted the number of anisakid roundworms 鈥� a common, tiny marine parasite 鈥� within the flesh.

The parasites had been killed during the canning process and, if eaten, would have posed no danger to a human consumer. But counting anisakids is one way to gauge how well a marine ecosystem is doing.

鈥淓veryone assumes that worms in your salmon is a sign that things have gone awry,鈥� said , a UW associate professor of aquatic and fishery sciences. 鈥淏ut the anisakid life cycle integrates many components of the food web. I see their presence as a signal that the fish on your plate came from a healthy ecosystem.鈥�

The research team reports in a published April 4 in Ecology & Evolution that anisakid worm levels rose for chum and pink salmon from 1979 to 2021, and stayed the same for coho and sockeye salmon.

鈥淎nisakids have a complex life cycle that requires many types of hosts,鈥� said Mastick, who is lead author on the paper. 鈥淪eeing their numbers rise over time, as we did with pink and chum salmon, indicates that these parasites were able to find all the right hosts and reproduce. That could indicate a stable or recovering ecosystem, with enough of the right hosts for anisakids.鈥�

Anisakids start out living freely in the ocean. They enter food webs when eaten by small marine invertebrates, such as krill. As that initial host gets eaten by another species, the worms come along for the ride. Infected krill, for example, could be eaten by a small fish, which in turn gets eaten by a larger fish, like salmon. This cycle continues until the anisakids end up in the intestine of a marine mammal, where they reproduce. The eggs are excreted back into the ocean to hatch and begin the cycle again with a new generation.

鈥淚f a host is not present 鈥� marine mammals, for example 鈥� anisakids can鈥檛 complete their life cycle and their numbers will drop,鈥� said Wood, who is senior author on the paper.

People cannot serve as hosts for anisakids. Consuming them in fully cooked fish poses little danger, because the worms are dead. But anisakids 鈥� also known as 鈥渟ushi worms鈥� or 鈥�sushi parasites鈥� 鈥� can cause symptoms similar to food poisoning or a rare condition called if ingested alive in raw or undercooked fish.

The , a Seattle-based trade group, donated the cans of salmon to Wood and her team. The association no longer needed the cans, which had been set aside each year for quality control purposes. Mastick and co-author Rachel Welicky, an assistant professor at Neumann University in Pennsylvania, experimented with different methods to dissect the canned fillets and look for anisakids. The worms are about a centimeter (0.4 inches) long and tend to coil up in the fish muscle. They found that pulling the fillets apart with forceps allowed the team to count worm corpses accurately with the aid of a dissecting microscope.

There are several explanations for the rise of anisakid levels in pink and chum salmon. In 1972, Congress passed the , which has allowed populations of seals, sea lions, orcas and other marine mammals to recover following years of decline.

鈥淎nisakids can only reproduce in the intestines of a marine mammal, so this could be a sign that, over our study period 鈥� from 1979 to 2021 鈥� anisakid levels were rising because of more opportunities to reproduce,鈥� said Mastick.

Other possible explanations include warming temperatures or positive impacts of the Clean Water Act, Mastick added.

The stable anisakid levels in coho and sockeye are harder to interpret because there are dozens of anisakid species, each with their own series of invertebrate, fish and mammal hosts. While the canning process left the tough anisakid exterior intact, it destroyed the softer parts of their anatomy that would have allowed identification of individual species.

Mastick and Wood believe this approach could be used to look at parasite levels in other canned fish, like sardines. They also hope this project will help make new, serendipitous connections that could fuel additional insight into ecosystems of the past.

鈥淭his study came about because people heard about our research through the grapevine,鈥� said Wood. 鈥淲e can only get these insights into ecosystems of the past by networking and making the connections to discover untapped sources of historical data.鈥�

Co-authors on the paper are UW undergraduate Aspen Katla, and Bruce Odegaard and Virginia Ng with the Seafood Products Association. The research was funded by the U.S. National Science Foundation, the Alfred P. Sloan Foundation, the Washington Research Foundation and the 天美影视传媒.

For more information, contact Mastick at nataliemastick@gmail.com, Welicky at rwelicky@gmail.com and Wood at chelwood@uw.edu.

Seafood is the world鈥檚 most highly traded food commodity, by value, and the product is hard to track from source to market. Reports of seafood mislabeling have increased over the past decade, but few studies have considered the overall environmental effects of this deceptive practice.

A study by Arizona State University, the 天美影视传媒 and other institutions examined the impacts of seafood mislabeling on the marine environment, including population health, the effectiveness of fishery management, and marine habitats and ecosystems.

The , recently published in the Proceedings of the National Academy of Sciences, show that some 190,000 to 250,000 tons of mislabeled seafood are sold each year in the U.S., making up 3.4% to 4.3% of all the seafood consumed. Farmed Atlantic salmon, often labeled and sold as Pacific salmon or rainbow trout, is the second-most-consumed mislabeled seafood product in the U.S., just behind shrimp.

Co-author , an assistant professor in the UW School of Marine and Environmental Affairs, helped to design a statistical analysis to compare the product on the label with the one that was actually consumed.

鈥淚t鈥檚 important to consider mislabeled consumption, rather than mislabeling rates, when thinking about the various biological and environmental impacts of mislabeling,鈥� Jardine said.

鈥淵ou can have a species that鈥檚 mislabeled the majority of the time, but if the consumption of that species is low, then the amount of the mislabeled product consumed is also low, and it may not be as big of a management concern.

鈥淥n the other hand, you can get products with low mislabeling rates and high consumption, meaning that a lot of the mislabeled product is being consumed. We find this is the case for giant tiger prawns being sold as white leg shrimp, and for Atlantic salmon being sold as Pacific salmon.鈥�

The authors used the program that assesses about 85% of seafood consumed in the U.S. and offers consumer recommendations for more sustainable choices. The authors combined those scores with mislabeling and consumption rates to compare the population health and fishery management of the species actually consumed versus the one on the label.

Genetic techniques can tell whether a seafood product is being marketed as a similar, higher value species, a switch that can happen at many points in the supply chain.

The most widely-consumed mislabeled product is shrimp, the most popular seafood in America. Imported giant tiger prawns, that are in Seafood Watch鈥檚 鈥淎void鈥� category, can end up labeled as white leg shrimp, in the 鈥淏est鈥� category.

Salmon came in second on the amount of mislabeled seafood consumed. Farmed Atlantic salmon, in the 鈥淎void鈥� category, can end up labeled as Pacific salmon or rainbow trout, typically in the 鈥淏est鈥� or 鈥淕ood鈥� category.

More generally, the study shows that false labeling tends to substitute a less sustainable product. Substituted seafood was 28% more likely to be imported from other countries, which often have weaker environmental laws than the ones covering the domestic seafood listed on the label.

鈥淚n the United States, we鈥檙e actually very good at managing our fisheries,鈥� said lead author , an assistant professor at Arizona State University鈥檚 School of Sustainability. 鈥淲e assess the stock so we know what鈥檚 out there. We set a catch limit. We have strong monitoring and enforcement capabilities to support fishers adhering to the limit. But many countries we import from do not have the same management capacity.鈥�

In 86% of cases, substitutes for wild-caught species came from fisheries that performed worse in terms of population impacts 鈥� species abundance, fishing mortality, and bycatch and discards 鈥� than the species on the label. Mislabeling also tended to disguise bad management practices: 78% of the substituted seafood had lower fishery management effectiveness than the product listed on the label.

鈥淭he expected species is often really well managed,鈥� Kroetz said.

Public attention has tended to focus on frequently mislabeled species even if Americans consume less of those products.

鈥淭here鈥檚 been a lot of media attention given to the mislabeling rates of a particular species, such as halibut and snapper,鈥� Jardine said. 鈥淏ut a big-picture analysis shows that we should also focus on other species if we are concerned about the environmental impacts.鈥�

The effects of seafood mislabeling are not just environmental, the authors write, but also economic and social, affecting seafood consumers and the sustainable fishing industry.

鈥淚f the seafood sustainability movement was better integrated with seafood mislabeling testing, rate estimation and regulatory tracing programs, we could provide the consumer with better information regarding the biological, social and economic implications of the products that they consume,鈥� Jardine said.

The study was funded by the Paul M. Angell Family Foundation and Resources for the Future. The work was also supported by the National Socio-Environmental Synthesis Center in Annapolis, Maryland, with funding from the National Science Foundation.

Other co-authors are Patrick Lee, Katrina Chicojay Moore and Andrew Steinkruger at the Washington, D.C.-based nonprofit Resources for the Future; C. Josh Donlan and Gloria Luque at the Williamsburg, Virginia-based nonprofit Advanced Conservation Strategies; Jessica Gephart at American University; and Cassandra Cole at Harvard University.

For more information, contact Jardine at jardine@uw.edu or Kroetz at kailin.kroetz@asu.edu.

Adapted from an ASU . See also a from Advanced Conservation Strategies.

A new study led by the 天美影视传媒 finds that the animals鈥� ability to breathe in that water may be key to where and when they thrive. The , published May 15 in Science Advances, uses recent understanding of water breathability and historical data to explain population cycles of the northern anchovy. The results for this key species could apply to other species in the current.

鈥淚f you’re worried about marine life off the west coast of North America, you’re worried about anchovies and other forage fish in the California Current. Ultimately it’s what underpins the food web,鈥� said lead author , a UW postdoctoral researcher in oceanography.

The study shows that species respond to how breathable the water is 鈥� a combination of the oxygen levels in the water and the species鈥� oxygen needs, which are affected by water temperature. The anchovy historical data matches this pattern, and it suggests that the southern part of their range could be uninhabitable by 2100.

鈥淐limate change isn鈥檛 just warming the oceans 鈥� it is causing oxygen to decrease, which could force fish and other ocean animals to move away from their normal range to find higher-oxygen waters,鈥� Howard said.

Anchovy populations are known to cycle through time, but the reasons have been mysterious. Other explanations 鈥� that drew on food supplies, predator-prey interactions, competition with other species, and temperature preferences 鈥� failed to fully explain the anchovy populations cycles from the1950s to today, which have been carefully recorded.

Since the late 1940s, the , or CalCOFI, a partnership between California state and federal agencies, has monitored marine life and conditions offshore. It was established after the economically devastating crash of the sardine fishery in the 1940s with the goal of avoiding another fisheries collapse and better understanding marine populations.

鈥淭hey weren’t just measuring anchovies, they were measuring everything they could get their hands on,鈥� Howard said. Because the anchovies are numerous and their populations soared after the sardine collapse, these fish provide a good record over time and space for the past half-century.

Previous research by the UW group showed that water “breathability,” the combined effects of temperature and oxygen levels, are key for marine animals鈥� survival. The 2015 research used models to combine the effects of warmer seawater that can hold less oxygen with marine animals鈥� increased metabolic needs in a warmer environment.

The new study also drew on a 2018 paper that analyzed the oxygen needs for various types of marine animals at different water temperatures. The two previous studies focused on the future, under climate change, and the distant past, for a major extinction event.

Researchers combined observations with ocean models to fill gaps in the data and showed that the breathability index changes over time and corresponds with when anchovy populations rise and fall, and when they move deeper or closer to shore.

鈥淭his study is the first one that demonstrates on a timescale of decades that a species is responding in really close alignment with this metabolic index 鈥� how breathable the ocean in its habitat has become,鈥� said senior author , a UW associate professor of oceanography. 鈥淚t adds a new, independent line of verification that species in the ocean are arranged in accordance with how breathable their habitats are.鈥�

The authors then looked at the extent of anchovy habitat in the future under climate change. Projected changes in the water conditions will likely make the southern part of the anchovies鈥� range, off the coasts of Mexico and Southern California, uninhabitable by 2100.

“We expect habitats to shift for all species that depend on oxygen for survival,” Howard said. “If we understand how these animals are responding to their environment, we can better predict how these populations will be affected as the conditions change.鈥�

Co-authors include graduate student Justin Penn and research scientist Hartmut Frenzel in the UW School of Oceanography; Daniele Bianchi, Lionel Renault and James McWilliams at the University of California, Los Angeles; Brad Seibel at the University of South Florida; and Fay莽al Kessouri and Martha Sutula at the Southern California Coastal Water Research Project. This research was funded by the National Science Foundation; the National Oceanic and Atmospheric Administration; California Sea Grant and the California Ocean Protection Council; and the Gordon and Betty Moore Foundation.

For more information, contact Howard at ehoward2@uw.edu and Deutsch at cdeutsch@uw.edu or 206-543-5189.

Researchers from the 天美影视传媒 are using high-tech tags to record the movements of swordfish 鈥� big, deep-water, migratory, open-ocean fish that are poorly studied 鈥� and get a window into the ocean depths they inhabit.

The researchers tagged five swordfish in late August off the coast of Miami: , , , and . Their movements can now be viewed in near-real time. And although swordfish are a prized catch, these ones aren’t at higher risk, researchers say, since the website updates only every few hours and these fast-swimming fish spend most of their time far from shore.

“These are animals that migrate into the ocean’s twilight zone that we know next to nothing about,” said , an oceanographer at the UW Applied Physics Laboratory. “Swordfish in different regions have very different behavior. We hope to learn more about these amazing animals and their environment as they migrate between regions.”

This is the first time satellite position tags have successfully been placed on swordfish caught off the coast of the United States.

Earlier tags on swordfish relied on measurements of temperature and light to approximate the animal’s position, which resulted in errors greater than 60 miles (100 km). The new tags act together as a pair: One records detailed temperature, light and depth measurements as the fish is swimming, while the other beams back the precise location when the fish surfaces each day.

By comparing the saved observations with computer reconstructions of ocean conditions, the researchers can re-create an individual fish’s precise travel path in three dimensions, allowing for the first time scientists to understand where these animals feed and providing new insight into deep-sea ecosystems.

Gaube and collaborator , a UW assistant professor of aquatic and fishery sciences, have placed similar satellite tags on other ocean predators, including great white sharks, , and .

“Swordfish are different from the surface-oriented fish that have been tagged, like sharks or whales 鈥� these are deep-sea fish,” Braun said. “But because they migrate up and down every day, they break the surface, and the new types of tags allow incredibly fast communication.”

Swordfish often jump at the surface, a behavior that helps make them a popular target for sport fishing.

“That’s why we’re so excited,” Braun said. “Swordfish are a particularly good platform to help us make observations in the deep ocean, while at the same time giving us a better understanding of why and how this predator makes a living.”

Recently, the UW researchers customized satellite tags made by of Redmond, Washington, to work on swordfish. These top predators swim long distances, commonly reach 10 feet (3 meters) in length, and are named for the long, flat bill they use to slash and injure prey.

The fish can swim at 50 miles per hour and typically spend the day at a third of a mile (550 meters) deep. They rise to the surface at night, along with millions of other fish and squid, upon which the swordfish feed.

A by Braun, Gaube and collaborators, published in June in the ICES Journal of Marine Science, analyzed 16 swordfish tagged with simpler tags in the western Atlantic, off Florida and the Grand Banks, and in the Northeast Atlantic, off the coast of Portugal. The results show that juvenile swordfish tagged off Portugal tended to stick to that area, while the mostly adult individuals tagged in the western Atlantic swam long distances between the Grand Banks off Newfoundland and the waters near Cuba.

With the new Florida-based project the team hopes not only to learn more about swordfish but to further explore the mesopelagic, or “twilight zone” of the Atlantic Ocean. These partially lit waters from a tenth to half a mile (200 to 800 meters) in depth are hard to reach and poorly studied, even as fishing is beginning to target these environments.

In January the researchers plan to tag more swordfish in the Red Sea, off the coast of Saudi Arabia.

“This will provide the baseline data we need to understand this ecosystem before it is exploited any further,” Gaube said.

The initial phase of the Florida swordfish-tagging project was funded by the Woods Hole Oceanographic Institution. Researchers are looking for , in the sport fishing community, environmental groups or others, to monitor other swordfish and gather more data.

Next the team is designing new tags that can hold more sensors that could measure properties such as acceleration, depth, water temperature, muscle temperature and stomach temperature. The next-generation tags could also include cameras that could be set to trigger based on various behaviors, such as when the fish dives to a certain depth. They hope to eventually use results from the Florida tagging project to guide shipboard sampling of the marine environment alongside swordfish 鈥渙ceanographers.鈥�

For more information, contact Gaube at pgaube@uw.edu or Braun at cdbraun@uw.edu.

An international group has taken a close look at how different types of bottom trawling affect the seabed. It finds that all trawling is not created equal 鈥� the most benign type removes 6 percent of the animal and plant life on the seabed each time the net passes, while the most other methods remove closer to a third. A 天美影视传媒 professor is among the main authors on the , led by Bangor University in the U.K. and published July 17 in the .

The meta-analysis looks at 70 previous studies of bottom trawling, most in the Eastern U.S. and Western Europe. It looks across those studies to compare the effects on the seabed of four techniques: , a common method that uses two “doors” towed vertically in the water or along the bottom to hold the net open; , which hold the net open with a heavy metal beam; , which drag a flat or toothed metal bar directly along the seafloor; and , which use water to loosen the seabed and collect animals that live in the sediment.

“We found that otter trawls penetrated the seabed 2.4 cm (0.94 inches) on average and caused the least amount of depletion of marine organisms, removing 6 percent of biota per trawl pass on the seabed,” first author at Bangor University said in a . “In contrast, we found that hydraulic dredges penetrated the seabed 16.1 cm (6.3 inches) on average and caused the greatest depletion, removing 41 percent of the biota per fishing pass.”

Depending on the type of fishing gear, penetration depth and environmental variables such as water depth and sediment composition, it took from 1.9 to 6.4 years for the seabed biota, or marine plants and animals, to recover.

“These findings fill an essential science gap that will inform policy and management strategies for sustainable fishing practices by enabling us to evaluate the trade-off between fish production for food, and the environmental cost of different harvesting techniques,” said , a UW fisheries professor and one of four co-authors who designed the study.

“There’s a common perception that you trawl the bottom and the ecosystem is destroyed,” Hilborn said. “This study shows that the most common kind of trawling, otter trawling, does not destroy the marine ecosystem, and places that are trawled once a year really won’t be very different from places that are not trawled at all.”

But the study doesn’t let otter trawling completely off the hook.

“We need to view these results in light of the footprint of each of these activities,” Hilborn added. “While otter trawling has the least impact per trawl pass, it is the most widely used of all the bottom fishing gear types and hence its effects are more widespread than are those of more specialized fishing gears, such as hydraulic dredges.”

The study is one part of a larger effort to catalogue the effects of different types of bottom trawling worldwide, known as the , which Hilborn leads with co-authors Michel Kaiser of Bangor University and Simon Jennings of the International Council for the Exploration of the Seas in Denmark. The group is doing other work to estimate how much bottom trawling takes place globally and thus determine the overall effect of bottom disturbance on the seafloor ecosystem. A previously published paper looked at how changes to the seafloor ecosystem affect the populations of fish that people are trying to catch.

Ultimately, the team aims to publish a set of fishing-industry “best practices” for the methods, equipment, density and frequency of bottom trawling.

The authors were unsurprised to find that otter trawling techniques are less destructive than hydraulic dredges. Similar findings came before, including a led by Kaiser, but that one looked at a smaller number of trawling studies. The authors since developed a scrupulous protocol and cast a wide net for the studies included in the current meta-analysis.

“This one is therefore somewhat bulletproof to the criticism that you have been choosing the studies,” Hilborn said. “Understanding how gear impacts the bottom, and species on the bottom, is important for a scientific understanding of the impacts of trawling.”

The project was initially jointly funded by the David and Lucile Packard Foundation and the Walton Family Foundation. Additional funding came from industry groups, including the Alaska Seafoods Cooperative; American Seafoods Group; Blumar Seafoods Denmark; Clearwater Seafoods; Espersen Group; Glacier Fish Company LLC; Gortons Inc.; Independent Fisheries Ltd., New Zealand; Nippon Suisan (USA), Inc.; Pacific Andes International Holdings, LLC.; Pesca Chiles, South Africa; San Arawa, South Africa; Sanford Ltd., New Zealand; Sealord Group Ltd., New Zealand; South African Trawling Association; and Trident Seafoods. Government funding for the study was supplied by the U.K. Department of Environment, Food & Rural Affairs; the European Union; the International Council for the Exploration of the Sea Science Fund; and the U.N. Food and Agriculture Organization.

Other co-authors are Marija Sciberras, Claire Szostek and Kathryn Hughes at Bangor University; Nick Ellis, Roland Pitcher and Tessa Mazor at the Commonwealth Scientific and Industrial Research Organization in Australia; Adriaan Rijnsdorp at the Institute for Marine Resources and Ecosystem Studies in the Netherlands; Robert McConnaughey at the Alaska Fisheries Science Center in Seattle; Ana Parma at the Centro Nacional Patagonico in Argentina; and Petri Suuronen at the U.N. Food and Agriculture Organization in Rome.

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For more information, contact Hilborn at rayh@uw.edu and Hiddink at j.hiddink@bangor.ac.uk or +441248382864.

Parts of this article were adapted from a Bangor University .

Researchers from the 天美影视传媒 and the National Oceanic and Atmospheric Administration have created a seasonal outlook for the Pacific Northwest waters, which would help tell if it’s going to be a great year for sardines or a poor crab season. A evaluating the forecast’s performance was published in June in the interdisciplinary, open-access journal .

“Ocean forecasting is a growing field, and the Pacific Northwest coast is a particularly good place to use this approach,” said lead author , a research scientist at the UW-based . “This paper is doing what the scientific community asks of a new tool, which is assessing how well it performs.”

The tool, called , or J-SCOPE, in summer 2013. The new paper is the first formal evaluation of how well it works. Analysis of the first three years of forecasts confirms that they do have measurable skill on seasonal timescales.

The seasonal for water oxygen, temperature, chlorophyll and pH along the coast of Washington, Oregon, Puget Sound and Canada’s Vancouver Island have been posted for the past three years on the UW-based Northwest Association of Networked Ocean Observing Systems website. That site now offers a comparison between the forecasted values and the long-term average, and the probability for different scenarios.

“The forecasts have been evolving over the years,” Siedlecki said. “We’re trying now to put the forecast in context 鈥� is this better or worse than in recent years?”

Analyses in the new paper show that the tool does especially well at the beginning of the spring upwelling season and matches observations most closely below the surface. This is good, Siedlecki said, because that’s exactly where measurements are scarce.

“Our tool has more skill in the subsurface, for things like bottom temperature and bottom oxygen,” she said. “That’s exciting because it can inform us where and when the low-oxygen and corrosive conditions that can be stressful to marine life would likely develop.”

The fall season is more storm-driven, she said, and consequently difficult to predict.

The tool takes long-term NOAA forecasts and combines those with a regional ocean model to produce the outlook. The goal is to eventually combine the ocean forecasts with fisheries management, so that decisions surrounding quotas could take into account the conditions for the species’ habitat during the coming season.

A was recently added and was the focus of a separate NOAA-led published this winter in Fisheries Oceanography. That forecast shows moderate skill in predicting sardine populations five or more months out.

The group now has funding from NOAA’s Northwest Fisheries Science Center to work on forecasts for , also known as Pacific whiting, since the widely-fished species lives below the surface and seems sensitive to oxygen concentrations. The researchers are interested in developing similar forecasts for salmon and other species.

Forecasted values include pH and aragonite, a calcium-containing mineral that marine animals use to harden their shells, so the tool can also help predict which months will have good conditions for growing shellfish.

“The oyster industry has already been treating the intake seawater coming into the hatcheries,” Siedlecki said. “If our forecasts can help the growers identify times of year that would be most suitable to set up juvenile oysters out in the open ocean, that would potentially help them get a leg up on changing conditions.”

For this summer, the outlook may be good news for ocean swimmers who like warm water and bottom-dwelling fish that sometimes struggle to breathe in the late summer or early fall.

“The current forecast is showing weak upwelling, warmer temperatures and higher oxygen than we’ve had in the past, so a bit of a relief in some ways for the ecosystem,” Siedlecki said.

Co-authors on the new paper are , , and at the UW and , , , and at NOAA.

Development of the tool was funded by NOAA through its Program, , and , and the NOAA-run .

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For more information, contact Siedlecki at 206-616-7328 or siedlesa@uw.edu.

Federal fisheries scientists have published a special section in this month’s issue of that outlines some considerations for coming decades. A 天美影视传媒 climate scientist helped biologists determine the long-term forecast for aquatic animals.

“When you look at projections for future climate change, there’s a big range of possible futures. And decision makers or biologists assessing impacts on a particular species want to know what’s the most likely future 鈥� they don’t want to use this huge range of uncertainty,” said , director of the UW-based .

Eight papers in the special section, led by the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, include case studies for species ranging from chinook salmon to steelhead to 82 different types of coral.

Snover is lead author of a on choosing and using climate-change scenarios to inform policy for endangered marine species.

“We tried to distill what climate scientists know in a way that would be useful for conservation biologists,” Snover said.

Choice of scenario will depend on the species 鈥� a salmon that moves between mountain streams and the open ocean, for example, is different from an animal that scurries along a sandy beach or that clings to a rock at the bottom of the ocean. The paper gives a choose-your-own-adventure approach to picking an appropriate set of climate projections.

“People who are trying to make decisions that account for climate change are often bewildered or overwhelmed by the large number of scenarios that are available, and think in many cases that they’re too uncertain to be used,” Snover said. “We’re establishing a strategy for choosing from this vast array of scenarios, and strategies that are defensible in litigious situations like the (Endangered Species Act).”

The paper’s broad-based approach could also apply to land animals, she said.

The paper also includes a “reality check” table to counter some common misperceptions about climate models 鈥� for example, that they differ too much to predict any useful trends, or that their uncertainty could be reduced by somehow finding the best model to use.

Trends that are certain to affect marine species, Snover said, include increasing ocean acidification, warmer water temperatures and changes in level and timing of stream flows.

“Despite the significant uncertainty that remains about potential future climates, we know enough to assess impacts and incorporate that information into conservation decisions,” Snover said.

Co-authors on the paper are Nathan Mantua, a former UW scientist now at NOAA’s National Marine Fisheries Service in Santa Cruz, Calif.; Jeremy Littell, a former UW scientist now at the U.S. Geological Survey’s Alaska Climate Science Center in Anchorage; Michael Alexander at NOAA’s Earth System Research Laboratory in Boulder, Colo.; Michelle McClure at NOAA’s National Marine Fisheries Service in Seattle; and Janet Nye at Stony Brook University. The research was partially supported by NOAA through the UW-based .

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For more information, contact Snover at 206-221-0222 or aksnover@uw.edu.

Michelle McClure is corresponding author for the special section. See NOAA’s news release, ““

That鈥檚 because the potential harvest of fish is only closely linked to abundance in 18 percent of 230 fish stocks assessed in a 天美影视传媒-led study, according to, UW professor of . For the other 82 percent of stocks, potential harvest of fish was primarily controlled by irregular shifts in environmental conditions or was random and not controlled by either abundance or shifts in environmental regimes.

Yet targets based on abundance of fish stocks are the mainstay of most management plans in the U.S. and a growing number of other countries: If a stock reaches certain abundance, it is thought, then potential harvest is maximized.

The are being published the week of Jan. 14 in the online early edition of the

鈥淭here have been competing ideas about productivity,鈥� Hilborn said. 鈥淥ne is that it depends primarily on abundance. The other is that productivity of a stock mostly depends on whether there鈥檚 a period of good conditions or a period of bad conditions.鈥�

鈥淲hat we鈥檝e done in this study is take 230 fish stocks and ask which of these explanations explains the data for each fish stock better,鈥� he said.

In contrast to the 18 percent of stocks where abundance controls productivity, there were 39 percent of stocks 鈥� more than two times as many 鈥� where productivity appears to jump between periods of high and low environmental regimes in an irregular fashion. Another 30 percent showed a weak relationship between productivity and abundance mixed in with irregular regime shifts. The remaining 13 percent fluctuated randomly.

鈥淩egime shifts can affect the number of young fish that reach adulthood, their ability to grow or how long they live. A shift can be caused by such things as changing ocean temperatures or increases in predators,鈥� said lead author a UW master鈥檚 student in aquatic and fishery sciences.

The authors write, 鈥淎lthough there may be little that fishery managers can do to avert shifts to a lower productivity state, improved methods for early detection of such shifts may permit managers to reduce harvest in time to avoid collapse.鈥�

Study co-author of Rutgers University says, 鈥淲e can think of fisheries like natural savings accounts, where we鈥檙e trying to harvest the interest 鈥� what fisheries scientists call the 鈥榮urplus production鈥� 鈥� without causing a long-term decline in the principal or abundance of mature adult fish.聽 Fisheries scientists have generally operated under the assumption that the 鈥榠nterest鈥� is determined by the abundance of mature adults.鈥�

鈥淥ur research shows that this is rarely the case. Instead of operating like a simple savings accounts, fisheries are more like volatile stocks where the rate of return is determined by a variety of complex factors outside the control of managers,鈥� Jensen said.

The findings don鈥檛 mean we shouldn鈥檛 attempt to manage fisheries or try to maintain fish stocks at high abundance, Hilborn said, because having plenty of fish benefits natural food chains and ecosystems and lowers the costs of harvesting fish.

This deserves particular attention, he said, as plans and timetables are formulated to rebuild an ever-increasing number of fish stocks. In many cases natural causes are the reason stocks are at low abundance, rather than overfishing, although fishing will cause even lower abundance in such cases, he said. Also, rebuilding fish stock abundance often won鈥檛 result in promised increases in sustainable yield, he said.

As the paper says, 鈥淚f fish populations experience substantial shifts in productivity unrelated to stock size, then management based on a single set of management targets (for example maximum sustainable yield) will be either inefficient or risky. If the targets are based on a higher productivity regime, then a shift to a low productivity regime will result in increased risk of overfishing. Conversely, management targets based on a lower productivity phase will result in overly cautious harvest during regimes of high productivity.鈥�

The fish stocks analyzed are part of a database initially created in 2006-7 in an effort led by Hilborn and Dalhousie University鈥檚 Boris Worm.

The fourth co-author is Ricardo Amoroso with the Centro Nacional Patag贸nico in Argentina. Funding came from the National Science Foundation and the National Oceanic and Atmospheric Administration.

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For more information:
–Hilborn, hilbornr@gmail.com
–Jensen, olaf.p.jensen@gmail.com