Archive for the Research Category

Nov 7 2014

Meteorologist explains El Niño, likely to develop this winter

Republished with permission of SEAFOODNEWS.COM November 6, 2014
In 1997-1998 abnormally high ocean temperatures off South America caused a collapse of the anchovy fisheries. Anchovies are a vital link in the food chain, and shortages can bring great hardship. Weather extremes associated with the event caused 2,000 deaths and $33 million (€26 million) in property damage. One commentator wrote that the warming event had “more energy than a million Hiroshima bombs”.

As it is not uncommon for an ocean warming to commence around Christmas, the fisherman of Peru call it El Niño, the Christ child. El Niño occurs when the temperature of the equatorial ocean west of South America is above normal, but its effects are more widespread.

Weather patterns in Indonesia and Australasia and the monsoons of southern Asia are affected. East Africa and North America also feel its impact. The heavy rainfall of Indonesia ceases, and droughts and wildfires are common in southeast Asia and Australia. Meanwhile, the mid- Pacific suffers a deluge.

During El Niño, the trade winds – which normally blow towards the west – weaken, allowing warm water from the western Pacific to slosh eastwards. El Niño lasts from a few months to a year or more and occurs about twice each decade, but its period is very irregular. It is linked to a see-saw pattern in which pressure in Tahiti is high when it is low in Darwin and vice versa. Together, this gives us Enso (El Niño southern oscillation).

Since February of 2014, some atmospheric models have been predicting the onset of El Nino, but it never quite materializes.

At the moment, there is evidence of warming along the South American Pacific coast, but that has not yet reached El Nino thresholds, despite disrupting the anchovy fisheries.

The current NOAA forecast says “Similar to last month, most models predict El Niño to develop during October-December 2014 and to continue into early 2015. However, the ongoing lack of clear atmosphere-ocean coupling and the latest NCEP CFSv2 model forecast have reduced confidence that El Niño will fully materialize. If El Niño does emerge, the forecaster consensus favors a weak event. In summary, there is a 58% chance of El Niño during the Northern Hemisphere winter, which is favored to last into the Northern Hemisphere spring 2015.

In Australia the Bureau of Meteorology says  “Weather conditions similar to El Nino will continue amid warming of the Pacific Ocean as thresholds for the event that brings drought to Asia and heavier-than-usual rains to South America may be reached by early next year.

Three of eight climate models may reach El Nino thresholds in January and another two remain just shy of the levels, the Australia’s Bureau of Meteorology said on its website today, maintaining an Oct. 21 outlook. The forecaster kept a watch status, indicating at least a 50 percent chance of a weak to moderate event, it said.

The bureau has pushed back projections for the onset of El Nino as changes to the atmosphere have failed to develop consistently. A weak event will probably develop by year end, MDA Weather Services predicted last month. El Ninos can roil agricultural markets as farmers contend with drought or too much rain. Palm oil, cocoa, coffee and sugar are among crops most at risk, Goldman Sachs Group Inc. has said.

“Sea surface temperatures in the tropical Pacific Ocean have warmed over the past two months, and the Southern Oscillation Index has remained negative, but indicators generally remain in the neutral range,” the bureau said. “The existence of warmer-than-average water in the tropical Pacific sub-surface supports a continuation of the current near-El Nino conditions.”

While sea-surface temperatures are warmer than normal across most areas in the tropical Pacific ocean, it still doesn’t qualify as an El Nino, Kyle Tapley, senior agricultural meteorologist at MDA said in response to e-mailed questions. Some additional warming could lead to the development of a weak El Nino, he said.
Oct 16 2014

Ecosystem-Based Fisheries Management

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NOAA strives to adopt an ecosystem-based approach throughout its broad ocean and coastal stewardship, science, and service programs. The goal of ecosystem-based management is to maintain ecosystems in a healthy, productive, and resilient condition so they can provide the services humans want and need. NOAA Fisheries refers to the ecosystem-based approach to management that is focused on the fisheries sector as ecosystem-based fisheries management (EBFM). While EBFM is directed towards fisheries management, a similar approach, accounting for ecosystem interactions and considerations, can be applied in the management of protected and other trust marine species.

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EBFM is a new way of looking at the management of living marine resources. The traditional management strategy for fisheries and other living marine resources is to focus on one species in isolation. For example, if a particular species’ population was declining, fishery managers might decide to reduce the annual catch limit the following year in an attempt to reduce overexploitation. However, fishing is only one variable that affects a species’ population. Additional elements come in to play, such as interactions with other species, the effects of environmental changes, or pollution and other stresses on habitat and water quality. To more effectively assess the health of any given fishery and to determine the best way to maintain it, fishery managers should take ecosystem considerations into account.

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Videos:

Fisheries in the California Current Ecosystem

Fisheries in the Northwest Atlantic Large Marine Ecosystem


 

 

View the original post here. header_noaa

Oct 15 2014

A Bird’s Eye View: Aerial Surveys of Nearshore Waters Provide Important Information for Managing Coastal Pelagic Fishes

aerialphoto_smAn unretouched aerial photo of a sardine school off Southern California

 

Since August 2012, CDFW’s Coastal Pelagic Species (CPS) Project and the California Wetfish Producers Association have been working together to develop a nearshore aerial survey program for southern California waters. The valuable data collected by the program may be used to set sustainable harvest limits and prevent overfishing of CPS, including Pacific sardine, Pacific mackerel, and northern anchovy.

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A primary focus of the program is developing scientifically rigorous aerial survey methods. Over the first four field seasons, Pacific sardine schools were mostly observed close to shore along either mainland or island coasts. Boat-based groundtruthing confirmed the accuracy of aerial fish identification, and provided critical biological and environmental data.

Map illustrating Pacific sardine observations

Starting in summer 2013, other CPS were quantified including northern anchovy and Pacific mackerel. Both aerial and boat survey methods have been refined to improve data collection efficiency and accuracy, and staff have begun integrating all CPS observations into the program. Information from the aerial surveys will help to increase our understanding of the abundance and distribution of CPS in southern California.sidebar

CDFW coordinates with NOAA Fisheries and other West Coast agencies through the Pacific Fishery Management Council (PFMC) to manage Pacific sardine and other CPS fisheries included in the federal CPS Fishery Management Plan. PFMC uses stock assessments to set sustainable harvest limits that prevent overfishing of CPS populations. Once enough data are collected, CDFW will request that the PFMC include the California aerial survey data in future stock assessments of Pacific sardine and, potentially, other CPS. California aerial surveys would complement other types of surveys currently included in stock assessments, such as the ship-based acoustic surveys and fish egg surveys conducted farther off shore.

For more information about Pacific sardine research and management, please visit CDFW’s Pacific sardine webpage.

 

 


View original post: CDFW Marine Management News

Sep 27 2014

A bigger chance of El Niño returning in 2014, but with little rain

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An image from the Jet Propulsion Laboratory shows a pair of warmer Kelvin waves heading towards the South American coast. NASA/JPL

 

El Niño can’t seem to make up its mind. After climatologists had previously stated that the chances of the warming weather phenomenon occurring this winter were becoming ever slimmer, it seems that there may now be a “glimmer of hope for a very modest comeback,” according to a press release from NASA’s Jet Propulsion Laboratory.

Ocean temperatures in equatorial Pacific had been rising earlier this year — indicating El Niño conditions. But they fell over the summer — dashing hopes for much needed rain.

Satellite images now show that warmer eastward “Kelvin waves” are headed towards the South American coast in the next two months, indicating a resurgent El Niño weather pattern. However, if El Niño triggers a wetter winter, it probably won’t mean drought-busting rain.

“If I was to compare where we are at with El Niño with where we were in ‘97-‘98, which was the Godzilla El Niño, I would call this one the gecko El Niño,” JPL climatologist Bill Patzert tells KPCC. He says El Niños can be small and modest and have little to no impact whatsoever on our rainfall.

NASA scientists will continue to monitor the Pacific for any changes.

Watch NASA video of El Niño forming earlier this year.


View original post: www.scpr.org

Sep 15 2014

Unusual North Pacific warmth jostles marine food chain

September 2014 | Contributed by Michael Milstein

 

Scientists across NOAA Fisheries are watching a persistent expanse of exceptionally warm water spanning the Gulf of Alaska that could send reverberations through the marine food web. The warm expanse appeared about a year ago and the longer it lingers, the greater potential it has to affect ocean life from jellyfish to salmon, researchers say.

“Right now it’s super warm all the way across the Pacific to Japan,” said Bill Peterson, an oceanographer with NOAA’s Northwest Fisheries Science Center in Newport, Ore., who has linked certain ocean indicators to salmon returns. “For a scientist it’s a very interesting time because when you see something like this that’s totally new you have opportunities to learn things you were never expecting.”

Not since records began has the region of the North Pacific Ocean been so warm for so long. The warm expanse has been characterized by sea surface temperatures as much as three degrees C (about 5.4 degrees F) higher than average, lasting for months, and appears on large- scale temperature maps as a red-orange mass of warm water many hundreds of miles across. Nick Bond of the Joint Institute for the Study of the Atmosphere and Ocean at the University of Washington earlier this summer nicknamed it “the blob.”

Indeed, there are three warm zones, said Nate Mantua, leader of the landscape ecology team at the Southwest Fisheries Science Center: The big blob dominating the Gulf of Alaska, a more recent expanse of exceptionally warm water in the Bering Sea and one that emerged off Southern California earlier this year. One exception to the warmth is a narrow strip of cold water along the Pacific Northwest Coast fed by upwelling from the deep ocean.

The situation does not match recognized patterns in ocean conditions such as El Niño Southern Oscillation or Pacific Decadal Oscillation, which are known to affect marine food webs. “It’s a strange and mixed bag out there,” Mantua said.

One possibility is that the PDO, a long-lived El Niño-like pattern, is shifting from an extended cold period dating to the late 1990s to a warm phase, said Toby Garfield, director of the Environmental Research Division at the Southwest Fisheries Science Center. Mantua said the PDO may have tipped into a warm state as early as January of this year.

But both scientists noted that the observed warm temperatures are higher and cover more of the northern Pacific than the PDO typically affects. For all but the Gulf of Alaska, the warm waters appear to lie in a relatively shallow layer near the surface. The cold near-shore conditions in the Pacific Northwest also don’t match the typical PDO pattern.

Warm ocean temperatures favor some species but not others. For instance, sardines and albacore tuna often thrive in warmer conditions. Pacific Coast salmon and steelhead rely on cold-water nutrients, which they may have found recently in the narrow margin of cold water along the Northwest coast. But if the warmth continues or expands Pacific Northwest salmon and steelhead could suffer in coming years.

“If the warming persists for the whole summer and fall, some of the critters that do well in a colder, more productive ocean could suffer reduced growth, poor reproductive success and population declines,” Mantua said. “This has happened to marine mammals, sea birds and Pacific salmon in the past. At the same time, species that do well in warmer conditions may experience increased growth, survival and abundance.”

Peterson recently advised the Northwest Power and Conservation Council that juvenile salmon and steelhead migrating from the Columbia River to the ocean this year and next may experience poor survival.

“The signs for salmon aren’t good based on our experience in the past,” Peterson said, “but we won’t really see the signal from this until those fish return in a few years.” The warm expanse in the Gulf of Alaska is a kind of climatic “hangover” from the same persistent atmospheric ridge of high pressure believed to have contributed to California’s extreme drought, Bond and Mantua said. The ridge suppressed storms and winds that commonly stir and cool the sea surface.

Other factors created the patch of warm water hugging the Central California Coast south to Baja California. A low-pressure trough between California and Hawaii weakened the winds that typically drive upwelling of deep, cold water along the California Coast. Without those winds waters off Southern California’s beaches have stayed unusually warm.

NOAA surveys off California in July found jellyfish called “sea nettles” and ocean sunfish, which the warmer waters likely carried closer to shore, Mantua said. Anglers have reported excellent fishing for warm water species including yellowfin tuna, yellowtail and dorado, also known as mahi-mahi.

Research surveys in the Gulf of Alaska this summer came across species such as pomfret, ocean sunfish, blue shark and thresher shark often associated with warmer water, said Joe Orsi of the Alaska Fisheries Science Center Auke Bay Laboratories in Juneau. He said temperatures in the upper 20 meters of water up to 65 kilometers offshore were 0.8 degrees C (about 1.4 degrees F) above normal in both June and July.

The potential arrival of El Niño later this year would likely reinforce the warming and its effects on marine ecosystems, Bond said. NOAA’s National Weather Service estimates a 65 percent chance El Niño will emerge in fall or early winter.

Mantua noted that fall in California generally brings even weaker winds and weaker upwelling, making it likely that the warm waters off Central California will persist and even expand northward regardless of a tropical El Niño.

mapUnusually warm temperatures dominate three areas of the North Pacific: the Bering Sea, Gulf of Alaska and an area off Southern California. The darker the red, the further above average the sea surface temperature. NOAA researchers are tracking the temperatures and their implications for marine life.

MolaNOAA research surveys in the Gulf of Alaska this summer turned up ocean sunfish, also known as mola, which are often associated with warmer waters.

ThresherSharkThresher sharks were among the species associated with warmer waters that turned up in research surveys in the Gulf of Alaska this summer.


Read original post here.

Sep 13 2014

Eating fish could lower your risk of hearing loss: study

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All it takes is two or more servings per week, and it doesn’t matter what kind you consume. The omega-3 fats in fish help preserve hearing, it seems.

AFP RELAXNEWS | Thursday, September 11, 2014, 12:46 PM
ElenaGaak /shutterstock.com According to recent research, two or more servings of fish per week could reduce women’s chances of hearing loss by as much as 20%.

According to researchers at Brigham and Women’s Hospital in Boston, two or more servings of fish per week could lower women’s risk of acquired hearing loss.

“Consumption of any type of fish (tuna, dark fish, light fish, or shellfish) tended to be associated with lower risk,” says corresponding author Dr. Sharon G. Curhan, MD, of BWH Channing Division of Network Medicine. “These findings suggest that diet may be important in the prevention of acquired hearing loss.”

In the massive cohort study, researchers tracked a total 65,215 women from 1991 to 2009.

Overall, participants self-reported 11,606 cases of incident hearing loss, and data analysis indicates that the women who consumed fish at least twice per week showed a 20% lower risk of hearing loss than the women who seldom ate fish.

Case-by-case observation revealed that higher consumption of each of the aforementioned fish types and increased intake of long-chain omega-3 polyunsaturated fatty acids (PUFA) in the women’s diets showed benefits for hearing preservation.

“Acquired hearing loss is a highly prevalent and often disabling chronic health condition,” says Dr. Curhan. “Although a decline in hearing is often considered an inevitable aspect of aging, the identification of several potentially modifiable risk factors has provided new insight into possibilities for prevention or delay of acquired hearing loss.”

The study was published in the journal American Journal of Clinical Nutrition.


 

Read the original post here.

Sep 9 2014

UN warns on ocean acidification as GHG levels soar

Carbon dioxide emissions in 2013 were largest on record since 1984, says World Meteorological Organization 

Shellfish are vulnerable to acidification, as acid in waters prevents species developing calcium shells  (Pic: NOAA)

Shellfish are vulnerable to acidification, as acid in waters prevents species developing calcium shells (Pic: NOAA)

By Ed King

Current levels of ocean acidification are “unprecedented” and directly linked to rising emissions of carbon dioxide, according to the UN’s World Meteorological Organization (WMO). 

In a greenhouse gas analysis of 2013, released on Tuesday, it said concentrations of CO2 in the air had risen more than any other year since 1984. Methane and nitrous oxide levels also rose.

Carbon dioxide levels in the atmosphere are now 142% higher than 1750, before the industrial revolution.

And the WMO said data showed the warming effect on the world’s climate due to greenhouse gases, known as radiative forcing, had risen 34% between 1990 and 2013.

“Carbon dioxide remains in the atmosphere for many hundreds of years and in the ocean for even longer,” said WMO secretary general Michel Jarraud.

“Past, present and future CO2 emissions will have a cumulative impact on both global warming and ocean acidification. The laws of physics are non-negotiable.”

Jarraud added the latest data should be used as a “scientific base for decision-making”.

World leaders are primed to meet in New York in two weeks for a UN summit to discuss options to reduce emissions of climate warming gases.

This report is the latest evidence of the levels of atmospheric gases burning fossil fuels has released.

A leaked draft of the UN’s IPCC climate science panel syntheses report, due out in November, stressed that “human influence on the climate system is clear”.

Earlier this year the Mauna Loa observatory in Hawaii recorded for the first time in recorded history that concentrations of carbon dioxide in the atmosphere had passed 400 parts per million (ppm).

Report: Alaska fisheries hit by rising acidifiction levels

Equally concerning, WMO scientists said the ability of the biosphere to absorb rising carbon levels had diminished, leaving the oceans to compensate.

“The ocean cushions the increase in CO2 that would otherwise occur in the atmosphere, but with far-reaching impacts,” it said in a press release.

“The current rate of ocean acidification appears unprecedented at least over the last 300 million years, according to an analysis in the report.”

Caused when the oceans suck in CO2, acidification is likely to lead to the decline of corals, algae, molluscs and some plankton, say scientists.

The ocean currently absorbs around a fourth of manmade CO2 emissions. The WMO said if emissions continue to rise, acidification is likely to accelerate until the 2050s.

Earlier this year the IPCC said ocean warming and acidification linked to rising CO2 levels would undermine food production and threaten the world’s poorest people.

Wendy Watson-Wright, executive secretary of the Intergovernmental Oceanographic Commission of UNESCO welcomed the WMO’s focus on oceans in its report.

“The inclusion of a section on ocean acidification in this issue of WMO’s greenhouse gas bulletin is appropriate and needed,” she said.

“It is high time the ocean, as the primary driver of the planet’s climate and attenuator of climate change, becomes a central part of climate change discussions.”


Read the original post at www.rtc.org:

http://www.rtcc.org/2014/09/09/un-warns-on-ocean-acidification-as-ghg-levels-soar/

Sep 4 2014

INNOVATIVE LAB GAUGES ACIDIFICATION EFFECTS ON MARINE SNAILS

Michael Maher working at the NOAA Northwest Fisheries Science Center Mukilteo field station with Mobile Ocean Acidification Treatment Systems (MOATS). Credit: NOAA NWFSC

Carbon dioxide scrubbers like those that clean the air in space stations.

Precision monitors and instruments.

Industrial parts used in wastewater treatment.

Michael Maher’s job was to assemble the pieces into one of the most sophisticated ocean acidification simulation systems yet developed. Ocean acidification is the decrease in ocean pH due to its absorption of carbon dioxide from the atmosphere – carbon dioxide forms an acid when it dissolves in water.

“You have tools available – they may not be designed for this purpose but you can try to make them all work together,” said Maher, a research biologist at NOAA Fisheries’ Northwest Fisheries Science Center in Seattle. “There wasn’t a blueprint or a kit you could order because nobody had really been trying to do this kind of thing before.”

The system that Maher and the ocean acidification research team built in the Science Center’s parking lot has provided new insight into the impacts of future ocean conditions on marine species. Researchers used it to examine what happens to small marine snails from Puget Sound when exposed to both current ocean conditions and the acidified conditions expected in the future. The research is described in a new paper in the online journal PLOS ONE reporting that current West Coast ocean waters are acidified enough to dissolve the shells of the snails, called pteropods.

The finding is not a surprise: Another NOAA-led team reported in April that shells of pteropods in near-shore habitat on the West Coast show signs of dissolution due to acidified waters. What is important about the new research is that it measured the extent of shell damage at escalating carbon dioxide concentrations, each translating to a different degree of acidification, in a controlled laboratory environment said Shallin Busch, a NOAA research ecologist.

The findings are a first step toward using the pteropod species examined in the study as a living barometer or indicator of ocean acidification along the West Coast.

“Our findings are a piece of the puzzle,” said Busch, the lead author of the new paper. “Now we know, yes, pteropods from the North Pacific are sensitive to ocean acidification. Now that we have confirmed their sensitivity, we need to look more closely at how pteropods are responding to current ocean conditions and what may happen in the future as carbon dioxide increases.”

Pteropods provide important nutrition for whales, seabirds and fish such as herring, salmon and mackerel, so changes in their populations could rattle through the marine food chain. Carbon emissions during the industrial era have lowered the average global ocean pH from 8.2 to 8.1, turning oceans slightly more acidic. West Coast waters are naturally acidified compared to other parts of the ocean so they may affect marine life such as pteropods sooner than acidifying waters elsewhere in the world.

The research also demonstrated the capacity of the NWFSC’s ocean acidification system to hold marine life at different carbon dioxide concentrations for extended periods. The system can control temperatures, oxygen levels and light for even more precise management of conditions during experiments.

“They are all dependent on each other – if you change the temperature, the pH will change,” Maher said. The system that carefully manages all the variables is “ a combination of machines and precisions instruments.”

The comprehensive controls allow researchers to isolate acidification as the cause of the shell damage, ruling out other factors that might otherwise be at play in a natural environment.

“There are not a lot of cases where we can definitively say, ‘This change is the result of acidification,’” said research ecologist Paul McElhany, Busch’s colleague at NWFSC. “It’s very hard to disentangle unless you know that’s the only thing changing. Experiments like this provide evidence about the effects of acidification alone.”

Busch said each member of the research team – Maher, McElhany and NOAA Hollings Scholar Patricia Thibodeau – brought individual skills to the research. The team has also developed a smaller and transportable version called a Mobile Ocean Acidification Treatment System, or MOATS that could be carried in the field or aboard research ships.

Thibodeau joined the research team for the summer of 2012 after her junior year at Bowdoin College in Maine. One of her initial tasks was to collect pteropods from Puget Sound by boat at night to stock the experimental system. Pteropods ascend in the water column at night to feed. The vertical movement naturally exposes them to varying carbon dioxide concentrations, which the ocean acidification system can simulate.

Later Thibodeau helped examine the shells of pteropods exposed to different concentrations of carbon dioxide. As with most science experiments where objectivity is paramount, she did not know which ones had been exposed to which concentrations when she rated the extent of damage to each shell.

“Sometimes biology can be so unpredictable, but this had such a clear outcome and relationship, it was very interesting to be a part of,” said Thibodeau, who just began work on her PhD at the Virginia Institute of Marine Science. “There is definitely a human component to the issue because so many of us eat oysters and clams and other species affected by ocean acidification. So what we know and what we do really makes a difference.”

NOAA Hollings Scholar, Patricia Thibodeau collects seawater from Puget Sound for chemistry measurement. Credit: NOAA NWFSC


Read original post at: http://oceanacidification.noaa.gov/WhatsNew.aspx

Sep 3 2014

In massive nod to success of West Coast industry and managers, Monterey Aquarium upgrades 21 species

Copyright © 2014 Seafoodnews.com – Posted with permission from SEAFOODNEWS.COM

SEAFOODNEWS.COM by John Sackton – Sept 3, 2014

In a massive nod to the success of US fishery managers, Monterey Bay Aquarium has upgraded its consumer guide on 21 west coast groundfish and rockfish species.

It now says all of these species – including sable fish, many species of rockfish sold as snapper in California, the various species of flatfish and other bottom trawl fish including Dover sole, petrale sole, starry flounder and sand dabs,  are rated either ‘best choice’ or ‘good alternative’.
“This is one of the great success stories about ecological and economic recovery of a commercially important fishery,” said Margaret Spring, vice president of conservation and science, and chief conservation officer for the Monterey Bay Aquarium.
Although Monterey Bay calls this “the most dramatic turnaround to date’, it actually reflects business as usual for the US fishery management system.
The West Coast groundfish fisheries were declared an economic disaster early in 2000, when landings and fishing income plummeted.  Many species were listed as being overfished, and in some cases bycatch limits on types of rockfish came down to virtually single fish.
“The turnaround in such a short time is unprecedented,” said Jennifer Dianto Kemmerly, director of the Seafood Watch program. “Fishermen, federal agencies and our environmental colleagues have put so much effort into groundfish recovery, and now we’re seeing the results of their work.”

In fact, the credit should go to the Pacific Fisheries Management Council, the Pacific States Marine Fisheries Commission, NMFS, and the industry that worked with them, along with the rationalization program that allowed for effort reductions to make the fishery more economically viable.
Although the Aquarium as an NGO credits the changes to the Magnuson act in 2006, actually the seeds of the recovery were planted much earlier.  The West coast and Alaska fisheries operated with hard TAC’s long before they became mandatory across the entire U.S.

Like other US fisheries management success stories, the recovery of West Coast groundfish and rockfish species relies on two primary principles that have been fully embraced by the seafood industry:
*scientifically set quotas for the total allowable catch, and
*comprehensive bycatch management based on industry formed cooperatives and real time bycatch reporting.

A third factor, beyond anyone’s control, has been the favorable environmental conditions on the West Coast that have allowed for stock recovery once the other two actions were in place.

Unfortunately, where the environmental conditions move against a fishery – as is happening in New England cod, the best fisheries science in the world cannot speed up a recovery.  However, fish history is replete with many species suffering declines to near zero abundance, and then recovering sharply as conditions improve.   Haddock in New England is a prime example, with the biomass recovering to levels not seen seen in 40 years.

In future articles we will document more about how this recovery took place, and the hard work that went into it.  But like the rooster who thought he caused the sun to rise, it is important for buyers to recognize that the rooster – in this case the Aquarium’s Seafood Watch – is announcing an event that was brought about through scientific management  and industry cooperation and discipline.

That is why for the seafood industry, it is great to have the recognition, whether it be MSC or the Aquarium or other recommend lists, but just like the rooster and the sunrise, the accolades are for the work we’ve already done, they are not the cause of the success.


John Sackton, Editor And Publisher
SeafoodNews.com 1-781-861-1441
Email comments to jsackton@seafood.com

Copyright © 2014 Seafoodnews.com

Aug 29 2014

Pacific Ocean acidity dissolving shells of key species

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Pacific Ocean acidity dissolving shells of key species: New research from NOAA sounding alarm bells about climate change

By Paul Rogers/San Jose Mercury News and Will Houston/The Times-Standard

In a troubling new discovery, scientists studying ocean waters off California, Oregon and Washington have found the first evidence that increasing acidity in the ocean is dissolving the shells of a key species of tiny sea creature at the base of the food chain.

The animals, a type of free-floating marine snail known as pteropods, are an important food source for salmon, herring, mackerel and other fish in the Pacific Ocean. Those fish are eaten not only by millions of people every year, but also by a wide variety of other sea creatures, from whales to dolphins to sea lions.

Humboldt State University Oceanography Department Head Jeffrey Abell has conducted several studies on ocean acidification off the coast of Trinidad, most recently in 2010. Abell said that deeper ocean waters are usually more acidic due to bacteria digesting dead organism matter, called detritus, which floats to the ocean floors. This digestion releases carbon dioxide, which reacts with water and causes the ocean to increase in acidity. Abell said Humboldt County’s shoreline is more prone to upwelling events in the late spring, which brings this deep, more acidic water to the surface.

“We don’t see a consistent exposure to acidic waters,” he said. “What we see is in the order of a few times to a dozen times a year during which the organisms, like pteropods, will be exposed to this corrosive water.”

Abell said Trinidad experienced about five of these events in 2007 — lasting no longer than a few days — but that number tripled to 15 episodes in 2010 that sometimes lasted over a week.

If the trend continues, climate change scientists say, it will imperil the ocean environment.

“These are alarm bells,” said Nina Bednarsek, a scientist with the National Oceanic and Atmospheric Administration in Seattle who helped lead the research. “This study makes us understand that we have made an impact on the ocean environment to the extent where we can actually see the shells dissolving right now.”

Scientists from NOAA and Oregon State University found that in waters near the West Coast shoreline, 53 percent of the tiny floating snails had shells that were severely dissolving — double the estimate from 200 years ago.

Until now, the impact on marine species from increasing ocean acidity because of climate change has been something that was tested in tanks in labs, but which was not considered an immediate concern like forest fires and droughts.

The new study, published in the Proceedings of the Royal Society B, a scientific journal based in England, changes that.

“The pteropods are like the canary in the coal mine. If this is affecting them, it is affecting everything in the ocean at some level,” said one of the nation’s top marine biologists, Steve Palumbi, director of Stanford University’s Hopkins Marine Station in Pacific Grove.

The vast majority of the world’s scientists — including those at NOAA, NASA, the National Academy of Sciences and the World Meteorological Organization — say the Earth’s temperature is rising because of humans burning fossil fuels like oil and coal. That burning pumps carbon dioxide into the atmosphere and traps heat, similar to a greenhouse. Concentrations of carbon dioxide in the Earth’s atmosphere have increased 25 percent since 1960 and are now at the highest levels in at least 800,000 years, according to measurements of air bubbles taken in ancient ice and other methods.

Many of the impacts are already being felt. Since the 1880s, when modern temperature records were first taken, the 10 hottest years have all occurred since 1998. Polar ice has melted, forest fires are burning in the West with increasing frequency, and the ocean has risen 8 inches since 1900 at the Golden Gate Bridge.

But what many people do not realize is that nearly a third of carbon dioxide emitted by humans is dissolved in the oceans. Some of that forms carbonic acid, which makes the ocean more corrosive.

Over the past 200 years, the ocean’s acidity has risen by roughly 30 percent. At the present rate, it is on track to rise by 70 percent by 2050 from preindustrial levels.

More acidic water can harm oysters, clams, corals and other species that have calcium carbonate shells. Generally speaking, increasing the acidity by 50 percent from current levels is enough to kill some marine species, tests in labs have shown.

Coastal Seafoods manager Greg Dale said Humboldt County’s oyster industry has actually thrived over the last two years, but rising ocean acidity is “something we watch carefully.”

“If this keeps going, and it means shutting ocean productivity, that’s when things get scary,” Dale said. “The ocean changes every year, but if you change the (acidity), you will lose a great deal.”

Abell said the current ocean acidification levels are not enough to harm the shells of oysters or abalone, which are made of calcite, but are enough to dissolve the shells of pteropods, which are made of aragonite.

“Pteropods are the most sensitive of this process; they’ll be kind of like an early warning system,” Abell said. “The present school of thought is that 50 years from now is when we’ll have to worry about the more sturdy shellfish, such as abalone.”

The new research on the marine snails does not show that increasingly acidic water is killing all of them, particularly older snails. But it is causing their shells to dissolve, which can make them more vulnerable to disease, slow their ability to evade predators and reduce their reproductive rates, the researchers said.

Some of the corrosive water near the shore could be a result of other types of pollution, such as runoff from fertilizer and sewage, said Stanford’s Palumbi, who was not involved in the NOAA research. But because the study found rates of the snails’ shells dissolving in deep water, far from the shore, human-caused carbon dioxide is the prime suspect, he added.

If people reduce emissions of fossil fuels, cutting carbon dioxide levels in the decades ahead, the damage to the oceans can still be limited, he said.

“But if we keep on the emissions profile we have now, by 2100 the oceans will be so harmed it’s hard to imagine them coming back from that in anything less than thousands of years,” Palumbi said.

“We are in a century of choice,” he said. “We can choose the way we want it to go.”


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