Archive for the Research Category

Mar 12 2020

West Coast Waters Shift Toward Productive Conditions, But Lingering Heat May “Tilt” Marine Ecosystem

Burgeoning populations of anchovy and a healthy crop of California sea lion pups reflected improved productivity off parts of the West Coast in 2019. However, lingering offshore heat worked against recovery of salmon stocks and reduced fishing success, a new analysis reports.

The California Current Ecosystem Status Report explains that ocean conditions off the West Coast remain unusually variable. This has been the case since the arrival of a major marine heatwave in 2014 known as “The Blob.” NOAA Fisheries’ two West Coast laboratories, the Northwest Fisheries Science Center and Southwest Fisheries Science Center, issue the report each year to the Pacific Fishery Management Council.

“There is not a real clear picture here,” said Chris Harvey, co-editor of the report developed by the two laboratories’ Integrated Ecosystem Assessment approach. The approach integrates physical, biological, economic, and importantly social conditions of the California Current marine ecosystem into the decision-making process. “On the one hand, we have a lot of anchovy out there. On the other hand, we also have a lot of warm water. That is not usually a sign of improved productivity.”

Lingering Warm Waters

A marine heatwave rivaling “The Blob” emerged in the Pacific in the second half of 2019 but waned by the beginning of 2020. The repeated warm events have left a remnant reservoir of heat deep in offshore waters. That could help “tilt” the system in a way that favors future heatwaves.

“Since a similar buildup and then recession occurred during 2013-2014, and we continue to observe anomalously warm water far offshore and retention of heat by deeper waters, it is unclear if we may see a resurgence of another heatwave in the summer of 2020,” the report says.

Warm conditions off the West Coast are generally associated with less productive conditions. Colder water from the north injects more energy-rich plankton into the marine ecosystem. Young salmon entering the ocean in cooler conditions, for example, grow bigger faster and support stronger adult salmon returns to the rivers where they spawn.

Ecological and Economic Indicators

The annual analysis hinges on a series of ecological and economic indicators. They range from the size of krill—small crustaceans that form the base of the food chain—to trends in fishery landings in port communities. Krill density was very low off much of the West Coast in 2019, and commercial fishery landings dropped 8 percent in 2018 compared to the year before.

Highlights of trends for several economic and ecological indicators outlined in the California Current Ecosystem Status Report.

The 2020 State of the California Current report introduces a new ecological indicator known as the “habitat compression index.” It reflects how warm offshore waters run up against cold, deeper waters that well up near the coast. The result is a narrow, “compressed” band of coastal ocean with cool, productive waters that draw fish and their predators together.

Other recent research found that during the Blob years, the compressed habitat brought humpback whales closer to shore to feed on booming numbers of anchovy. That put many whales in the same waters where Dungeness crab fishermen set their traps, and record numbers of whales became entangled in the fishing lines.

The habitat compression index will provide a running barometer of how offshore heat is affecting nearshore waters and the species that depend on them. “We will continue to study this metric in relation to other indicators in hopes of understanding why coastal impacts in recent years have been so severe,” the report says.

Fisheries landings on the West Coast have seen big ups and downs in recent years. There have been large catches of hake but fewer landings of salmon and coastal pelagic species such as sardines. Commercial landings in 2018, the last year with data available, fell 8 percent, with declines in shrimp, market squid, and many groundfish species. Dungeness crab, however, is a bright spot, with increased landings in recent years.

“Through presenting ecosystem trends, our goal is to provide the Council and the public with a snapshot of the health of the California Current ecosystem,” said Toby Garfield, the co-editor of the report. “Understanding these changes is critical to preserving the productivity and sustainability of West Coast fisheries.”


Original post: https://www.fisheries.noaa.gov/

Feb 4 2020

Fisheries Management Is Actually Working, Global Analysis Shows

Increasing fish stocks around the world give credibility to strong management and the importance of fisheries data

Story modified from the original press release issued by the University of Washington 

Nearly half of the fish caught worldwide are from stocks that are scientifically monitored and, on average, these stocks are increasing in abundance. According to a new global analysis, effective management appears to be the main reason these stocks are at sustainable levels or rebuilding successfully.

The analysis, which incorporated fisheries data from around the world, was conducted by an international research team supported by the Science for Nature and People Partnership. Their results were published January 13th in the Proceedings of the National Academy of Sciences.

The results show that fisheries management works when applied, and the solution for sustaining fisheries around the world is implementing effective fisheries management, the authors explained.

“There is a narrative that fish stocks are declining around the world, that fisheries management is failing and we need new solutions — and it’s totally wrong,” said lead author Ray Hilborn, a professor in the University of Washington School of Aquatic and Fishery Sciences. “Fish stocks are increasing in many places, and we already know how to solve problems through effective fisheries management.”

The project builds on a decade-long international collaboration to assemble estimates of the status of fish stocks — or distinct populations of fish — around the world, from Peru to the Mediterranean, and to Japan. This information helps scientists and managers know where overfishing is occurring or where some areas could support even more fishing.

The team’s database includes information on nearly half of the world’s fish catch, or about 880 fish stocks, providing perhaps the most comprehensive picture worldwide of the health and status of fish populations.

“The key is we want to know how well we are doing, where we need to improve, and what the problems are,” Hilborn said.

By pairing information about fish stocks with recently published data on fisheries management activities in about 30 countries, the researchers found that more intense management led to healthy or improving fish stocks, while little to no management led to overfishing and poor stock status.

“With these data, we could test whether fisheries management allows stocks to recover. We found that, emphatically, the answer is yes,” said co-author Christopher Costello, a professor of environmental and resource economics at University of California, Santa Barbara, and a board member with Environmental Defense Fund. “This gives credibility to the fishery managers and governments around the world that are willing to take strong actions.”

To be successful, management should be tailored to fit the characteristics of the different fisheries and the needs of specific countries and regions. The main goal should be to reduce the total fishing pressure when it is too high, and find ways to incentivize fishing fleets to value healthy fish stocks.

“There isn’t really a one-size-fits-all management approach,” Costello said. “We need to design the way we manage fisheries so that fishermen around the world have a long-term stake in the health of the ocean.”

Still, there are data-deficient areas of the world. Scientific estimates of the status of most fish stocks in South Asia and Southeast Asia are not available, and fisheries in India, Indonesia and China alone represent 30% to 40% of the world’s fish catch that is essentially unassessed.

“There are still big gaps in the data and these gaps are more difficult to fill,” said co-author Ana Parma, a principal scientist at Argentina’s National Scientific and Technical Research Council and a member of The Nature Conservancy global board. “This is because the available information on smaller fisheries is more scattered, has not been standardized and is harder to collate, or because fisheries in many regions are not regularly monitored.”

Hilborn and collaborators recently presented this work at the Food and Agriculture Organization of the United Nations’ International Symposium on Fisheries Sustainability in Rome.

Other co-authors are from University of Victoria, University of Cape Town, National Institute of Fisheries Research (Morocco), Rutgers University, Seikai National Fisheries Research Institute Japan, CSIRO Oceans and Atmosphere, Fisheries New Zealand, Wildlife Conservation Society, Marine and Freshwater Research Center (Argentina), European Commission, Galway-Mayo Institute of Technology, Center for the Study of Marine Systems, Sustainable Fisheries Partnership, The Nature Conservancy, and the Food and Agriculture Organization of the United Nations.

The research was funded by the Science for Nature and People Partnership (SNAPP), a collaboration between the National Center for Ecological Analysis and Synthesis at UC Santa Barbara, The Nature Conservancy, and Wildlife Conservation Society. Individual authors received funding from The Nature Conservancy, The Wildlife Conservation Society, the Walton Family Foundation, Environmental Defense Fund, the Richard C. and Lois M. Worthington Endowed Professorship in Fisheries Management and donations from 12 fishing companies.


Original post: https://www.nceas.ucsb.edu/

Jan 29 2020

‘Blob’ research shows ecological effects that halted fishing and hiked whale entanglements

Unprecedented environmental changes inspire new online tools to better spot them next time

NOAA Fisheries West Coast Region

An ecological pileup of unprecedented changes in the ocean off the West Coast beginning about 2014 led to record entanglements of humpback and other whales, putting the region’s most valuable commercial fishery at risk, new research shows.

The findings reflect a new management challenge brought about by a changing climate, recovering whale populations, and fishing pressure, according to the new research published in Nature Communications. The situation calls for new measures to alert fishermen to the risk of entanglements and help managers adjust to more rapid and frequent changes in the marine environment.

“We need to put information in the hands of those who can use it, at a time when it can make a difference,” said Jarrod Santora, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center (SWFSC) in Santa Cruz, California, and lead author of the research. “We are seeing changes coming at us in ways they never have before.”

Santora and his colleagues are developing a website that will use oceanographic data to forecast the areas where whales are most likely to be feeding off the West Coast. Crab fishermen could then use the information to help decide where–and where not–to set their traps. It may also help managers decide where and when to open–or close–fishing.

The new research teases out the ecological causes and effects that contributed to the spike in reported whale entanglements. Many involved traps set for Dungeness crab, said Nathan Mantua, a research scientist at the SWFSC and coauthor of the research. Reported entanglements have since dropped off but remain higher than before the increase.

“We had all these things that weren’t part of anyone’s experience come together in this remarkable three-year period,” he said.

Conflict Prompts Improved Communication

The entanglements have also prompted environmental lawsuits that threaten to restrict crab fishing. At the same time, though, the focus on entanglements has led to better communication and conversation between fishermen, environmental groups, and managers. Collaborative working groups have also developed tools to better anticipate and avoid entanglement risk.

“If the working group knew then what we know now, it wouldn’t have happened,” said John Mellor, a crab fisherman from San Francisco, referencing the increased entanglements. “The more we understand the whole picture, the better chance we have to mitigate the impacts.”

The driver behind many of the environmental changes was an unprecedented marine heatwave that took hold in 2014. It became known as “the warm Blob,” because of the large expanse of unusually high temperatures that dominated waters off the West Coast. The warm temperatures attracted subtropical species rarely seen in the region. The krill that humpback whales typically feed on grew scarce.

The whales switched to feed instead on high concentrations of anchovy that the warm, less productive waters had squeezed into a narrow band near the coast.

At the same time, the higher temperatures fueled a record bloom of toxic algae. It shut down crabbing on the West Coast from November 2015 through March 2016. When toxin levels eased and the Dungeness season finally opened, fishermen set multitudes of crab traps in that same narrow band where many whales were feeding.

NOAA Fisheries’ West Coast Region confirmed a then-record 53 whale entanglements in 2015 and 55 in 2016.

The scientists developed a new measure for ocean conditions called the Habitat Compression Index. It tracks the width of the productive band and how tightly species are coalescing there.

Whale Numbers Reflect Unprecedented Change

Research Biologist Karin Forney, also from the SWFSC and a coauthor of the research, lives in Moss Landing, California. She has a view of Monterey Bay and has long seen occasional humpback whales feeding just offshore. During the “the Blob” years, she would regularly see 30 to 40 whales from her front windows. Local whale watch boats made two to three trips a day to keep up with the demand.

Some 300 whales were counted at once in Monterey Bay.

“In our lifetimes living here, that was unprecedented,” she said. “We knew something dramatically different was pulling these whales closer to shore.”

She is also part of a NOAA team trained to free entangled whales.

“We were on call every day for weeks, with simultaneous reports of two or three entangled whales, so we could respond if they were sighted again,” she said. The team disentangled a few, while others were never seen again.

The lesson of the research, Forney said, is that scientists and fishermen must share information. They can help each other understand how complex environmental connections affect marine species and fisheries. Communication may be one of their most important tools as environmental changes come ever faster.

“Things are dynamic, and things are changing,” she said. “That is not going away.”

Humpback whales feed on anchovy off the Coast of California. New research shows that warm ocean temperatures pushed whales into the same water as crab fishermen, and whale entanglements increased. CREDIT: John Calambokidis/Cascadia Research Collective

 


Original post: https://www.eurekalert.org/

Jan 25 2020

Dungeness crab larvae already showing effects of coastal acidification

This infographic shows the location of larval Dungeness crab sampling in 2016, examples of impacts from ocean acidification, as well as photos of a larval (left) and adult (right) crab. Credit: Nina Bednarsek, SSCWRP.

 

A new NOAA-funded study has documented for the first time that ocean acidification along the US Pacific Northwest coast is impacting the shells and sensory organs of some young Dungeness crab, a prized crustacean that supports the most valuable fishery on the West Coast.

Analysis of samples collected during a 2016 NOAA research cruise identified examples of damage to the carapace, or upper shell, of numerous larval Dungeness crabs, as well as the loss of hair-like sensory structures crabs use to orient themselves to their surroundings.

The study was published in the journal Science of the Total Environment.

Impacts to wild crab mirror results of laboratory study

Prior to this study, scientists thought that Dungeness crab were not vulnerable to current levels of ocean acidification, although a laboratory study conducted on Dungeness crab larvae by NOAA’s Northwest Fisheries Science Center in 2016 found that their development and survival suffered under pH levels expected in the future.

“This is the first study that demonstrates that larval crabs are already affected by ocean acidification in the natural environment, and builds on previous understanding of ocean acidification impacts on pteropods,” said lead author Nina Bednarsek, senior scientist with the Southern California Coastal Water Research Project. “If the crabs are affected already, we really need to make sure we start to pay much more attention to various components of the food chain before it is too late.”

What is ocean acidification?
Ocean acidification refers to a reduction in the pH of ocean water, primarily caused by the uptake of carbon dioxide from the atmosphere over long time spans. When CO2 is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions. This increase causes the seawater to increase its acidity and causes carbonate ions to be less abundant.

Carbonate ions are an important building block of structures such as sea shells and coral skeletons that rely on using calcium carbonate for structural growth. Decreases in carbonate ions can make building and maintaining shells and other calcium carbonate structures difficult for calcifying organisms such as oysters, clams, sea urchins, crabs, corals, and some kinds of shelled plankton, such as pteropods.

Close examination reveals patterns of damage
In this study, examination under a high-magnification, scanning electron microscope revealed that the corrosive conditions of coastal waters had affected portions of the fragile, still-developing external shell and legs of the tiny, almost translucent post-larval Dungeness crabs, leaving tell-tale features, such as abnormal ridging structures and scarred surfaces. This could, in turn, impair larval survival by altering swimming behaviors and competence, including the ability to regulate buoyancy, maintain vertical position, and avoid predators.

One of the more important findings of this study was that crabs showing signs of carapace dissolution were smaller than other larvae. This was disconcerting, scientists said, because the damage during the crab’s larval stages could cause potential developmental delays that could increase energy demands and interfere with maturation.

Sensory organ damage seen for the first time
In a surprising discovery, the team found that the low pH water in some coastal areas damaged the canals where hair-like bristles called mechanoreceptors stick out from the shell. These receptors transmit important chemical and mechanical sensations to the crab, and may help crabs navigate their environment. Examination showed that carapace dissolution destabilizes the attachment of the mechanoreceptor anchor, resulting in them falling out in some individuals.

This is a new aspect of crustacean sensitivity to ocean acidification that has not been previously reported. The team hypothesize that the absence or damage of mechanoreceptors within their neuritic canals may in part explain potential aberrant behavioral patterns, such as slower movement, less tactile recognition, and prolonged searching time, as well as impaired swimming, that have been observed in various crustacean species exposed to low pH conditions in laboratory settings.

“We found dissolution impacts to the crab larvae that were not expected to occur until much later in this century,” said Richard Feely, Senior Scientist with NOAA’s Pacific Marine Environmental Laboratory and one of the co-authors of the study.

Combining observations and modelling work, the research team, which included scientists from JISAO, NOAA’s cooperative institute at the University of Washington, from the University of Connecticut, and from Quebec, Britain and Slovenia, demonstrated that the impacts of dissolution were the most severe in the coastal habitats, where crabs grow and mature.

Previous research has indicated that Dungeness crab may also be vulnerable to future declines due to lack of availability of prey – including bivalves such as clams and other bottom-dwelling invertebrate species.

More research needed
Bednarsek emphasized that more research will be needed to determine whether the external dissolution seen in crabs at this early life stage could carry over into later life stages, including the reproductively active adult stage, and what the potential consequences may be for the population dynamics.

“If these larval crab need to divert energy to repair their exoskeletons, and are smaller as a result, the percentage that make it to adulthood will be at best variable, and likely go down in the long-term,” she said.

Ocean acidification is a major concern for West Coast fishery managers, said Rich Childers, Washington Department of Fish and Wildlife’s ocean acidification policy lead. “These data and results give state and tribal fishery managers and policy makers information that’s vital for harvest and conservation planning.”

The research was supported by the NOAA’s Ocean Acidification Program and NOAA’s Pacific Marine Environmental Laboratory.

NOAA Research News, 23 January 2020. Article.


Original post: https://news-oceanacidification-icc.org/

Jan 17 2020

Fish populations around the world are improving

Fish populations around the world are improving

January 16, 2020 — The following was released by Sustainable Fisheries UW:

Let’s enjoy some unequivocal, inarguable good news: a paper published today in PNAS, Hilborn et al. 2020, shows that on average, scientifically-assessed fish populations around the world are healthy or improving. And, for fish populations that are not doing well, there is a clear roadmap to sustainability. With Australia on fire and scares of World War III, the start of 2020 and the new decade has been awful; hopefully Hilborn et al. 2020 can kickstart a decade of ocean optimism.

Hilborn et al. 2020 counters the perception that fish populations around the world are declining and the only solution is closing vast swaths of ocean to fishing. Instead, Hilborn et al. 2020 argues that increasing scientific, management, and enforcement capacity will lead to more abundant and sustainable oceans. The major takeaway of the paper is that fishery management works—when fisheries are managed, they are sustained. The key is following the science-to-management blueprint. Scientific data collection and fishery assessment comes first, then fishing regulation and enforcement of fishing policies. With the blueprint in place, most fisheries around the world are sustainable or improving.

The paper uses updates to the RAM Legacy Stock Assessment Database, a decades-long project to assemble data on fish populations that are scientifically assessed. As of 2019, the database contains data on 882 marine fish populations, representing about half of reported wild-caught seafood. In 2009, the database contained data on only 166, representing a much smaller proportion of global seafood. Researchers have spent the last 10 years adding to the database, and with today’s publication, update the global status of fish stocks. They found that, on average, fish populations are above target levels. Not every stock is doing well, but on average, things are much better than they were 2 decades ago. How nice: an environmental story where things are better now than they were in the past!

The paper describes the global status of fish stocks, but it also tells the story of fishery sustainability from the past 50 years.

Read the full story at Sustainable Fisheries UW


Original post: Copyright © 2020 Stove Boat LLC, All rights reserved.
Saving Seafood | 202-595-1212 | savingseafood.org

Jan 15 2020

Release — Fisheries management is actually working, global analysis shows

FROM: Michelle Ma
University of Washington
206-543-2580
mcma@uw.edu
(NOTE: Researcher contact information at end)

EMBARGOED BY THE PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES
For public release at 12 p.m. Pacific / 3 p.m. Eastern on Monday, Jan. 13, 2020

Fisheries management is actually working, global analysis shows

Nearly half of the fish caught worldwide are from stocks that are scientifically monitored and, on average, are increasing in abundance. Effective management appears to be the main reason these stocks are at sustainable levels or successfully rebuilding.

That is the main finding of an international project led by the University of Washington to compile and analyze data from fisheries around the world. The results were published Jan. 13 in the Proceedings of the National Academy of Sciences.

“There is a narrative that fish stocks are declining around the world, that fisheries management is failing and we need new solutions — and it’s totally wrong,” said lead author Ray Hilborn, a professor in the UW School of Aquatic and Fishery Sciences. “Fish stocks are not all declining around the world. They are increasing in many places, and we already know how to solve problems through effective fisheries management.”

The project builds on a decade-long international collaboration to assemble estimates of the status of fish stocks — or distinct populations of fish — around the world. This information helps scientists and managers know where overfishing is occurring, or where some areas could support even more fishing. Now the team’s database includes information on nearly half of the world’s fish catch, up from about 20% represented in the last compilation in 2009.

“The key is, we want to know how well we are doing, where we need to improve, and what the problems are,” Hilborn said. “Given that most countries are trying to provide long-term sustainable yield of their fisheries, we want to know where we are overfishing, and where there is potential for more yield in places we’re not fully exploiting.”

Over the past decade, the research team built a network of collaborators in countries and regions throughout the world, inputting their data on valuable fish populations in places such as the Mediterranean, Peru, Chile, Russia, Japan and northwest Africa. Now about 880 fish stocks are included in the database, giving a much more comprehensive picture worldwide of the health and status of fish populations.

Still, most of the fish stocks in South Asia and Southeast Asia do not have scientific estimates of health and status available. Fisheries in India, Indonesia and China alone represent 30% to 40% of the world’s fish catch that is essentially unassessed.

“There are still big gaps in the data and these gaps are more difficult to fill,” said co-author Ana Parma, a principal scientist at Argentina’s National Scientific and Technical Research Council and a member of The Nature Conservancy global board. “This is because the available information on smaller fisheries is more scattered, has not been standardized and is harder to collate, or because fisheries in many regions are not regularly monitored.”

The researchers paired information about fish stocks with recently published data on fisheries management activities in about 30 countries. This analysis found that more intense management led to healthy or improving fish stocks, while little to no management led to overfishing and poor stock status.

These results show that fisheries management works when applied, and the solution for sustaining fisheries around the world is implementing effective fisheries management, the authors explained.

“With the data we were able to assemble, we could test whether fisheries management allows stocks to recover. We found that, emphatically, the answer is yes,” said co-author Christopher Costello, a professor of environmental and resource economics at University of California, Santa Barbara, and a board member with Environmental Defense Fund. “This really gives credibility to the fishery managers and governments around the world that are willing to take strong actions.”

Fisheries management should be tailored to fit the characteristics of the different fisheries and the needs of specific countries and regions for it to be successful. Approaches that have been effective in many large-scale industrial fisheries in developed countries cannot be expected to work for small-scale fisheries, especially in regions with limited economic and technical resources and weak governance systems, Parma said.

The main goal should be to reduce the total fishing pressure when it is too high, and find ways to incentivize fishing fleets to value healthy fish stocks.

“There isn’t really a one-size-fits-all management approach,” Costello said. “We need to design the way we manage fisheries so that fishermen around the world have a long-term stake in the health of the ocean.”

Other co-authors are from University of Victoria, University of Cape Town, National Institute of Fisheries Research (Morocco), Rutgers University, Seikai National Fisheries Research Institute Japan, CSIRO Oceans and Atmosphere, Fisheries New Zealand, Wildlife Conservation Society, Marine and Freshwater Research Center (Argentina), European Commission, Galway-Mayo Institute of Technology, Center for the Study of Marine Systems, Sustainable Fisheries Partnership, The Nature Conservancy, and the Food and Agriculture Organization of the United Nations.

Hilborn and collaborators recently presented this work at the Food and Agriculture Organization of the United Nations’ International Symposium on Fisheries Sustainability in Rome.

The research was funded by the National Center for Ecological Analysis and Synthesis Science for Nature and People Partnership. Individual authors received funding from The Nature Conservancy, The Wildlife Conservation Society, the Walton Family Foundation, Environmental Defense Fund, the Richard C. and Lois M. Worthington Endowed Professorship in Fisheries Management and donations from 12 fishing companies.

###

For more information, contact Hilborn at rayh@uw.edu, Parma at anaparma@gmail.com and Costello at costello@bren.ucsb.edu.

More information is available at Sustainable Fisheries UW, an effort to communicate the science, policies and human dimensions of sustainable fisheries.

Jan 15 2020

Earth’s oceans are hotter than ever — and getting warmer faster

The world’s oceans hit their warmest level in recorded history in 2019, according to a study published Monday that provides more evidence that Earth is warming at an accelerated pace.

The analysis, which also found that ocean temperatures in the last decade have been the warmest on record, shows the impact of human-caused warming on the planet’s oceans and suggests that sea-level rise, ocean acidification and extreme weather events could worsen as the oceans continue to absorb so much heat.

“The pace of warming has increased about 500 percent since the late 1980s,” said one of the study’s authors, John Abraham, a professor of thermal sciences at the University of St. Thomas in St. Paul, Minnesota. “The findings, to be honest, were not unexpected. Warming is continuing, it has accelerated, and it is unabated. Unless we do something significant and quickly, it’s really dire news.”

Abraham and his colleagues found that the rate of ocean warming accelerated from 1987 to 2019 to nearly 4½ times the rate of warming from 1955 to 1986.

According to the study, published Monday in the journal Advances in Atmospheric Sciences, average ocean temperatures in 2019 were 0.075 degrees Celsius (0.135 degrees Fahrenheit) above the 1981-2019 average. While that may seem minuscule, it represents an enormous amount of heat spread out across the world’s oceans, according to the study’s lead author, Lijing Cheng, an associate professor at the Institute of Atmospheric Physics in Beijing.

“The amount of heat we have put in the world’s oceans in the past 25 years equals to 3.6 billion Hiroshima atom bomb explosions,” Cheng said in a statement.

The study, conducted by an international team of 14 scientists, found that oceans have absorbed more than 90 percent of the heat trapped on Earth from greenhouse gas emissions since 1970.

“Oceans are the biggest reservoir of heat and therefore the best indicator of climate change,” Abraham said. “If you want to know how fast the Earth is warming, look at the oceans.”

Scientists are worried by the trend because warmer oceans can increase severe weather and intensify storms.

“It’s like putting weather on steroids,” Johnson said. “We did a study a few years ago that showed Hurricane Harvey in Texas passed over a very warm body of water, and that greatly increased the amount of rainfall.”

Harvey unleashed more than 60 inches of rain over southeastern Texas in 2017, and scientists have said climate change will make storms rainier overall.

Warmer oceans also expand and melt ice, speeding the rise in sea levels and increasing the risk to coastal communities and low-lying infrastructure, said Nick Bond, a professor of atmospheric sciences at the University of Washington in Seattle, who wasn’t involved with the new study. According to the U.N. Intergovernmental Panel on Climate Change, average global sea levels could rise by 0.95 feet to 3.61 feet by the end of the century.

“From Miami Beach to Bangladesh — as sea levels continue to creep up, it’s just going to become less viable to live in these places,” Bond said.

He added that there are other significant societal implications, such as the effect that warming oceans may have on the chemistry and biology of the world’s oceans.

When carbon dioxide is absorbed and mixes with ocean water, chemical reactions make the water more acidic. Some sea creatures and ecosystems, such as corals, struggle with this type of acidification, but Bond said scientists don’t yet know the extent of the potential fallout.

“There are going to be winners and losers, but we don’t know how that will all play out,” he said. “It’s a very complicated system, and we don’t fully understand which species will have to shift their range, which ones may go extinct or which ones may prosper.”

Katie Matthews, chief scientist at Oceana, an ocean conservation organization in Washington, D.C., said ocean warming could have enormous impacts on fisheries around the world, particularly in the tropics.

“The tropics are the areas that have the largest number of people reliant on fish for nutrition, food security and livelihood,” she said. “It’s really unfortunate that the most vulnerable and at-risk populations are going to be the ones most affected.”

The study, which incorporated measurements from the National Oceanic and Atmospheric Administration, used data on ocean temperatures dating to the 1950s. The measurements included recordings of temperatures extending from the sea surface to depths of more than 6,500 feet.

Average ocean temperatures over the years have followed the warming trend, but Abraham said some of the most pronounced warming has taken place in the South Atlantic Ocean, in the Pacific Ocean off the coast of Japan, and in the waters south of Australia.

Abraham said he hopes the findings will spark climate action around the world.

“This isn’t a political issue,” he said. “This is a science issue, and our measurements are telling us that this is a problem and we need to take action.”


Dec 23 2019

California coastal waters rising in acidity at alarming rate, study finds

A commercial fishing boat heads out of Morro Bay. A study released Monday found that waters off the California coast are acidifying faster than the rest of the ocean. (Al Seib / Los Angeles Times)

 

Waters off the California coast are acidifying twice as fast as the global average, scientists found, threatening major fisheries and sounding the alarm that the ocean can absorb only so much more of the world’s carbon emissions.

A new study led by the National Oceanic and Atmospheric Administration also made an unexpected connection between acidification and a climate cycle known as the Pacific Decadal Oscillation — the same shifting forces that other scientists say have a played a big role in the higher and faster rates of sea level rise hitting California in recent years.

El Niño and La Niña cycles, researchers found, also add stress to these extreme changes in the ocean’s chemistry.

These findings come at a time when record amounts of emissions have already exacerbated the stress on the marine environment. When carbon dioxide mixes with seawater, it undergoes chemical reactions that increase the water’s acidity.

Across the globe, coral reefs are dying, oysters and clams are struggling to build their shells, and fish seem to be losing their sense of smell and direction. Harmful algal blooms are getting more toxic — and occurring more frequently. Researchers are barely keeping up with these new issues while still trying to understand what’s happening under the sea.

Scientists call it the other major, but less talked about, CO2 problem.

The ocean covers more than 70% of the Earth’s surface and has long been the unsung hero of climate change. It has absorbed more than a quarter of the carbon dioxide released by humans since the Industrial Revolution, and about 90% of the resulting heat — helping the air we breathe at the expense of a souring sea.

Here in California’s coastal backyard, some of the nation’s most economically valuable fisheries are also the most vulnerable. Scientists for years have worried that the West Coast would face some of the earliest, most severe changes in ocean carbon chemistry.

Many have noted how West Coast waters seemed to acidify faster, but there was little historical data to turn to. Ocean acidification has become a field of research only in recent decades, so information has been limited to what scientists have since started monitoring and discovering.

This study, published Monday in the journal Nature Geoscience, came up with a creative way to confirm these greater rates of acidification. Researchers collected and analyzed a specific type of shell on the seafloor — and used these data to reconstruct a 100-year history of acidification along the West Coast.

“This is the first time that we have any sort of record that takes it back to the beginning of the [last] century,” said Emily Osborne, a NOAA researcher and lead author of the study. “Prior to this, we didn’t have a time series that was long enough to really reveal the relationship between ocean acidification” and these climate cycles.

The study analyzed almost 2,000 shells of a tiny animal called foraminifera. Every day, these shells — about the size of a grain of sand — rain down onto the seafloor and are eventually covered by sediment.

Scientists took core samples from the Santa Barbara basin — where the seafloor is relatively undisturbed by worms and bottom-feeding fish — and used the pristine layers of sediment to create a vertical snapshot of the ocean’s history.

Seen under a microscope, these colorful spots are foraminifera shells taken from the mud of core samples off the California coast. Scientists studied these shells dating back 100 years to measure acidification rates in the ocean. (NOAA)

 

The more acidic the ocean, the more difficult it is for shellfish to build their shells. So using a microscope and other tools, the research team measured the changes in thickness of these shells and were able to estimate the ocean’s acidity level during the years that the foraminifera were alive.

“We can read the deposits like pages in a book,” said Osborne, a scientist for NOAA’s Ocean Acidification Program. “In Santa Barbara, there are just beautifully preserved laminated records of the seafloor that allow us to generate these high-resolution reconstructions.”

Image of a foraminifera shell magnified 650 times by a scanning electron microscope. (NOAA)

 

Using these modern calibrations, the scientists concluded that the waters off the California coast had a 0.21 decline in pH over a 100-year period dating back to 1895 (the lower the pH, the greater the acidity, according to the logarithmic pH scale of 0 to 14 ). This is more than double the decline — 0.1 pH — that scientists estimate the ocean has experienced on average worldwide.

From these records, Osborne could see clear changes whenever El Niño or other climate cycles shifted the ocean’s chemistry more dramatically. The data revealed an unexpected connection to the Pacific Decadal Oscillation, a warming and cooling cycle involving strong winds that pull warmer surface water on or offshore. The swings in upwelling of more nutrient- and carbon-rich waters alleviated or amplified the acidification.

This climate pattern has already been connected to shifts in sea level rise and other effects along the West Coast. More data and better understanding of these connections will help scientists adjust their models as they project what to expect in the future.

So there’s this bottom-up pressure from the oscillation, as well as the top-down stress of carbon dioxide from the atmosphere getting absorbed by surface water, Osborne said. “This makes the extremes even more extreme. It’s like a double whammy for this region of the world.”

Restoring the ocean’s kelp forests and other marine vegetation will help sequester some of this carbon, but ultimately, how much worse this all gets depends on the choices people make in the next decade. Efforts to rein in human-produced greenhouse gases play a significant role in temperature, wind patterns, acidification and how fast the sea will rise.

“While the ocean has served a very important role in mitigating climate change by absorbing CO2 from the atmosphere, there’s a capacity at which the ocean can’t absorb anymore,” Osborne said. “From this study, and so many other published studies, there’s no question that the answer is to curb our carbon emissions.”


Original post: https://www.latimes.com/california/story/2019-12-16/ocean-acidification-california

Sep 25 2019

The Intergovernmental Panel on Climate Change (IPCC) releases its Special Report on the Ocean and the Cryosphere in a Changing Climate

The new IPCC Special Report, released today,  is the first IPCC Report to focus on the role of the ocean in the global climate and the effects of climate change on the ocean. Ocean acidification is extensively covered throughout the report. A few OA-relevant excerpts from the Summary for Policymakers are cited below:

OBSERVED CHANGES AND IMPACTS

Observed Physical Changes

A2.5 The ocean has taken up between 20–30% (very likely) of total anthropogenic CO2 emissions since the 1980s causing further ocean acidification. Open ocean surface pH has declined by a very likely range of 0.017–0.027 pH units per decade since the late 1980s, with the decline in surface ocean pH very likely to have already emerged from background natural variability for more than 95% of the ocean surface area. {3.2.1; 5.2.2; Box 5.1; Figures SPM.1, SPM.2}

Observed Impacts on Ecosystems

A5.3 Eastern Boundary Upwelling Systems (EBUS) are amongst the most productive ocean ecosystems. Increasing ocean acidification and oxygen loss are negatively impacting two of the four major upwelling systems: the California Current and Humboldt Current (high confidence). Ocean acidification and decrease in oxygen level in the California Current upwelling system have altered ecosystem structure, with direct negative impacts on biomass production and species composition (medium confidence). {Box 5.3, Figure SPM.2}

A6.4 Warm-water coral reefs and rocky shores dominated by immobile, calcifying (e.g., shell and skeleton producing) organisms such as corals, barnacles and mussels, are currently impacted by extreme temperatures and ocean acidification (high confidence). Marine heatwaves have already resulted in large-scale coral bleaching events at increasing frequency (very high confidence) causing worldwide reef degradation since 1997, and recovery is slow (more than 15 years) if it occurs (high confidence). Prolonged periods of high environmental temperature and dehydration of the organisms pose high risk to rocky shore ecosystems (high confidence). {SR1.5; 5.3.4, 5.3.5, 6.4.2.1, Figure SPM.2}

PROJECTED CHANGES AND RISKS

Projected Physical Changes

B2.3 Continued carbon uptake by the ocean by 2100 is virtually certain to exacerbate ocean acidification. Open ocean surface pH is projected to decrease by around 0.3 pH units by 2081–2100, relative to 2006– 2015, under RCP8.5 (virtually certain). For RCP8.5, there are elevated risks for keystone aragonite shell-forming species due to crossing an aragonite stability threshold year-round in the Polar and sub-Polar Oceans by 2081–2100 (very likely). For RCP2.6, these conditions will be avoided this century (very likely), but some eastern boundary upwelling systems are projected to remain vulnerable (high confidence). {3.2.3, 5.2.2, Box 5.1, Box 5.3, Figure SPM.1}

B2.4 Climate conditions, unprecedented since the preindustrial period, are developing in the ocean, elevating risks for open ocean ecosystems. Surface acidification and warming have already emerged in the historical period (very likely). Oxygen loss between 100 and 600 m depth is projected to emerge over 59–80% of the ocean area by 2031– 2050 under RCP8.5 (very likely). The projected time of emergence for five primary drivers of marine ecosystem change (surface warming and acidification, oxygen loss, nitrate content and net primary production change) are all prior to 2100 for over 60% of the ocean area under RCP8.5 and over 30% under RCP2.6 (very likely). {Annex I: Glossary, Box 5.1, Box 5.1 Figure 1}

Projected Risks for Ecosystems

B5.3 Warming, ocean acidification, reduced seasonal sea ice extent and continued loss of multi-year sea ice are projected to impact polar marine ecosystems through direct and indirect effects on habitats, populations and their viability (medium confidence). The geographical range of Arctic marine species, including marine mammals, birds and fish is projected to contract, while the range of some sub-Arctic fish communities is projected to expand, further increasing pressure on high-Arctic species (medium confidence). In the Southern Ocean, the habitat of Antarctic krill, a key prey species for penguins, seals and whales, is projected to contract southwards under both RCP2.6 and RCP8.5 (medium confidence). {3.2.2, 3.2.3, 5.2.3}

B5.4 Ocean warming, oxygen loss, acidification and a decrease in flux of organic carbon from the surface to the deep ocean are projected to harm habitat-forming cold-water corals, which support high biodiversity, partly through decreased calcification, increased dissolution of skeletons, and bioerosion (medium confidence). Vulnerability and risks are highest where and when temperature and oxygen conditions both reach values outside species’ tolerance ranges (medium confidence). {Box 5.2, Figure SPM.3}

B6.1 All coastal ecosystems assessed are projected to face increasing risk level, from moderate to high risk under RCP2.6 to high to very high risk under RCP8.5 by 2100. Intertidal rocky shore ecosystems are projected to be at very high risk by 2100 under RCP8.5 (medium confidence) due to exposure to warming, especially during marine heatwaves, as well as to acidification, sea level rise, loss of calcifying species and biodiversity (high confidence). Ocean acidification challenges these ecosystems and further limits their habitat suitability (medium confidence) by inhibiting recovery through reduced calcification and enhanced bioerosion. The decline of kelp forests is projected to continue in temperate regions due to warming, particularly under the projected intensification of marine heatwaves, with high risk of local extinctions under RCP8.5 (medium confidence). {5.3, 5.3.5, 5.3.6, 5.3.7, 6.4.2, Figure SPM.3}

The full Report, as well as the Summary for Policymakers are available here.


Originally published: https://news-oceanacidification-icc.org/

Aug 6 2019

NOAA Releases 2018 Status of Stocks With New Emphasis on Environmental Impacts

The words “overfishing” and “overfished” are still used to describe seafood species with too high of a catch rate or too low of a population, but for the first time NOAA’s “Status of the Stocks 2018”, released last Friday, attributes impacts from global warming as causing changes in the sustainability status of fish stocks. It may be time to find new adjectives.

The bottom line for the report is the list, titled “Overfishing and Overfished Stocks As of December 31, 2018.” The good news in the 2018 report is that seven stocks came off the Overfishing List. But zero came off the Overfished List, five stocks were added to the Overfising List and eight stocks were added to the Overfished List.

The operative terms were defined by Alan Risenhoover, director of NOAA’s Office of Sustainable Fisheries, noted in Friday’s press conference.

“ ‘Overfishing’ is the rate of harvest, or the number of fish removed per year: one percent, ten percent, etc.,” Risenhoover said. “ ‘Overfished’ means that over time, overfishing creates a non-sustainable stock status for those species. It refers to overall population size.”

But it was environmental conditions that were listed as significant reasons for adding species to the lists, not what the fleets were doing.

“The total number of stocks listed as overfished increased, due to a number of factors including those outside the control of domestic fisheries management,” the report noted.

“The eight stocks added to the 2018 overfished list illustrate numerous challenges inherent in fisheries management,” the report author wrote.

“Environmental change, habitat degradation, and international fishing contributed to the status of the eight new overfished stocks. For example, relatively warm water conditions may be impacting the growth and reproduction of the cold-water Saint Matthew Island blue king crab. This stock has never been subject to overfishing and directed fishing for this crab has been prohibited since 2016.

“Warm ocean conditions, including the warm “Blob” in the northeast Pacific Ocean, reduced the number of spawning coho salmon returning to their natal rivers, and both Chinook and coho salmon have been impacted by habitat degradation caused by drought and lack of sufficient water for spawning,” the report noted.

“During the past 5 years, several of the fisheries for these salmon stocks have been declared fishery disasters under the MSA by the Secretary of Commerce due to factors beyond the control of fishery managers.”

NOAA partners with regional councils to manage the nation’s fisheries stocks, and works closely with other international bodies to manage stocks that are highly migratory and harvested globally. All management bodies use similar scientific principles to maintain sustainable populations, but very few include impacts of global warming or environmental changes, although almost all managers are aware of those impacts.

Managing fisheries on an ecosystem basis, rather than each species or species stock alone, was put into place by most U.S. management agencies in recent years. In Alaska, the effort to expand that to include weather systems, Arctic ice conditions, and stock migrations are underway.

Part of the problem is keeping up with rapidly changing warming ocean temperatures, especially in the north Atlantic and north Pacific. The nation’s most abundant fishing grounds in the Bering Sea are being impacted harder and sooner than many other productive areas because of the recent lack of sea ice and Arctic warming.

There are no models of how fisheries stocks react to these fundamental environmental shifts because the shifts have not happened on the current scale. Managers are aware of migration changes that may help some species and hurt others, depending on food availability, predators, and environmental conditions.

It is the biggest challenge NOAA Fisheries has faced perhaps in its history — how to manage stocks in a rapidly changing ocean.

For 2018, 43 fish stocks are on the Overfished List, with 28 on the Overfishing List. New England has the most Overfished species, with 15; the North Pacific has the least with 2 (St. Matthew Island and the Pribilof Island blue king crab stocks.)

After 9 years in a rebuilding plan with strict management, including a prohibition on landings, Gulf of Maine smooth skate was declared rebuilt in 2018.

“The renewed fishing opportunity and market for barndoor skate wings, following its rebuilt status, may lay the market foundation for a smooth skate fishery in the future,” the report noted.

Photo Credit: NOAA Fisheries

Peggy Parker
SeafoodNews.com
1-781-861-1441
peggyparker@urnerbarry.com


Original post: SeafoodNews.com — reposted with permission.