Archive for the View from the Ocean Category

Feb 26 2019

Environmental Impact Displacement in Fisheries & Food

A recent policy perspective paper in Conservation Letters, Lewison et al. 2019 (open access), summarized several examples of environmental impact ‘displacement,’ an important policy concept with implications for fisheries and food.

Examples of environmental impact displacement

Environmental impact displacement is when a conservation policy designed to reduce impact in one area, displaces it to another area, sometimes making the overall problem worse. Researchers cite sea turtle bycatch in swordfish fisheries as an example of displacement in fisheries: U.S. Pacific swordfish fishing was curtailed to protect sea turtles caught as bycatch. However, lower U.S. catch increased foreign swordfish demand which ended up killing more sea turtles as foreign swordfish fisheries had higher rates of bycatch.

ProPublica and the New York Times recently published a long exposé about how a U.S. policy meant to reduce carbon emissions (by increasing biofuel use) raised demand for palm oil in Southeast Asia, which actually increased emissions and jumpstarted the palm oil/biodiversity crisis (this example is also cited in Lewison et al.).

The viral Ocean Cleanup Project is another example of environmental displacement; the crowdfunded campaign was trying to remove marine debris from the great Pacific garbage patch by sweeping a giant net-like object across the ocean. However, if it had worked as intended (it broke), it would have killed many more organisms than the trash it was trying to remove from the ocean.

Environmental displacement in fisheries & food

The concept of environmental impact displacement is important to consider in fisheries management and marine conservation. The swordfish case above is a good example of displacement in individual fisheries, but there are other areas of fishery management that should consider environmental impact displacement. For example, no-take marine protected areas often increase fishing pressure outside the area being protected, nullifying the protection. In some cases, displacing fishing pressure benefits the ecosystem, but often it does not.

Zooming out in scale raises larger systemic questions about food: Consider fisheries and marine conservation as part of a broader, global system of food and ecological preservation. A legitimate argument can be made that fulfilling fishery potential and consuming more seafood is good for the planet—it provides low-carbon, low-impact protein.

As the developing world continues to acquire wealth, global demand for animal-protein will continue to rise. The more seafood that is eaten in place of cow, the better, since bovine farming is the largest driver of rainforest and biodiversity loss on the planet. Not only is seafood the lowest-impact animal protein, several kinds of seafood (e.g. farmed bivalves and wild-caught pelagics) are among the lowest impact foods of any kind.

Solutions to environmental displacement

Lewison et al. 2019 outline ways to reduce environmental impact displacement that can be applied to fisheries management and global food systems. The first step, researchers state, is explicitly considering displacement in policy design, scoping, and evaluation. Fishery managers should evaluate and understand the biological, economic, and social outcomes of proposed policies to avoid issues like accidentally increasing turtle bycatch across the world or raising fishing pressure in an area surrounding an MPA.

Other ways to avoid displacement include:

  • Think large-scale to consider all economic/biological/social relationships
  • Enact both demand-side and supply-side policies
  • International trade agreements and cooperation as a holistic approach to global conservation

Conservation groups should consider the global food system and environmental impact displacement in their advocacy; policy makers and natural resource managers should consider environmental impact displacement in their decision-making processes. Conservation will be more effective with a larger, broad approach—particularly with fisheries and food. Lewison et al. 2019 is open access and available here.


Original post: https://sustainablefisheries-uw.org/environmental-impact-displacement/

Feb 25 2019

Methane bubbling up from ocean floor provides a surprising food source for crabs, Oregon State University research shows

Oregon State University researchers have documented tanner crabs feeding at a methane seep site off British Columbia. Tanner crabs are also known as ‘snow crabs’ and sold as food. It is the first time a commercially harvested species has been known to feed at methane sites.The methane shouldn’t cause any health concerns and, in fact, it may provide an alternative energy source for seafloor-dwelling marine species. [Oregon State University]

 

Climate change will result in less ocean-borne food falling into the deep sea, scientists say. But that likely won’t be a problem for tanner crabs, according to a recent discovery by Oregon State University researchers.

The long-legged orange crabs — one of three species that crabbers harvest and sell as snow crabs — vigorously feed at methane seeps, where the gas bubbles up from the ocean floor.

“The thinking used to be that the marine food web relied almost solely on phytoplankton dropping down through the water column and fertilizing the depths,” OSU Marine Ecologist Andrew Thurber said in a statement. “Now we know that this viewpoint isn’t complete and there may be many more facets to it.”

Thurber co-authored a study that the journal Frontiers in Marine Science just published. The study details how scientists found tanner crabs in eating frenzies around a methane seep in the floor of the Pacific Ocean off British Columbia. It is one the first times that a commercially harvested seafood has been found to rely on methane seeps.

Methane seeps appear to be serving up food to seafloor-dwelling species, such as tanner crabs. This would be a hedge against climate change because nearly all models predict less food will drop into the deep sea in coming years.

“Tanner crabs likely are not the only species to get energy from methane seeps, which really haven’t been studied all that much,” Thurber said. “We used to think there were, maybe, five of them off the Pacific Northwest coast and now research is showing that there are at least 1,500 seep sites — and probably a lot more. … They are all over the world, so the idea that they may provide an energy source is quite intriguing.”

Researchers first noticed tanner crabs bunching up around methane seeps in 2012 off the British Columbia coast. The crabs sifted through sediment at the bubbling seeps. Mats of bacteria form around the seeps and the crabs munch on those.

Underwater video shows methane building up below tanner crabs hanging out at seeps and eventually flipping them. The entertaining video drew researchers to wonder why the crabs were gathered around the seeps in the first place.

OSU teamed up with scientists from the University of Victoria in Canada. The National Science Foundation in the U.S. provided support for the study.

Off the Oregon Coast, Pacific sole and black cod have been seen near methane seeps. Like the crabs, the fish are harvested.

But seafood lovers need not worry about what their food is eating. Researchers say methane seeps create nontoxic environments.

Sarah Seabook, the lead author of the study and a Ph.D. candidate at OSU, said scientists examined the guts and tissues of tanner crabs to confirm they were feeding around methane seeps.

″… We can apply these new techniques to other species and find out if the use of methane seeps as a food source is more widespread than just tanner crabs,” she said in a statement.


Original post: https://www.registerguard.com/news/20190225/methane-bubbling-up-from-ocean-floor-provides-surprising-food-source-for-crabs-oregon-state-university-research-shows

Jan 15 2019

Understanding Ocean Acidification Impacts to California’s Living Marine Resources – Ocean Science Trust

Helping the State visualize what’s at stake as oceans acidify



Now Available: http://www.oceansciencetrust.org/wp-content/uploads/2019/01/OST-OA-Impacts-Infographic-Final.pdf

A summary of the latest research on ocean acidification (OA) impacts to important species and ecosystems in California, from crab to squid, rockfish to urchins. This tool provides a tangible illustration of our current knowledge to support decision-makers in prioritizing efforts and resources to address OA impacts.

Ocean Science Trust, working closely with scientists at UC Davis Bodega Marine Lab, the Ocean Protection Council (OPC) and other partners, undertook this synthesis to help identify data gaps and prioritize where to allocate resources to further increase understanding of OA impacts to California fishery resources.

OVERVIEW: UNDERSTANDING OA RISKS TO CALIFORNIA’S LIVING MARINE RESOURCES

Ocean acidification is a complex issue that has the potential to alter marine food webs and ecosystems in California, with direct and indirect impacts to valuable marine fisheries and the aquaculture industry. Currently, state agencies working to understand the risks OA poses to coastal species, ecosystems, and human communities – an essential step to helping those at risk prepare for what’s at stake as coastal oceans continue to acidify.

VISUALIZING IMPACTS OF OA TO LIVING MARINE RESOURCES IN CALIFORNIA

As a first step towards illuminating potential natural resource management solutions, Ocean Science Trust worked closely with scientists at UC Davis Bodega Marine Lab, the Ocean Protection Council and other partners to demonstrate the potential impacts of OA on important species and ecosystems in California. We undertook a synthesis of current scientific understanding and developed communications material for use by resources managers. The species included in the synthesis represent a diverse subset of species considered as ocean climate indicators, commercially, recreationally, and/or ecologically important. This list was selected by the project team and vetted and augmented by OPC, CDFW, and aquaculture representatives.

WORKSHOP: DEFINING OCEAN ACIDIFICATION HOTSPOTS IN CALIFORNIA

Building on this assessment, Ocean Science Trust hosted a workshop in November 2018, to help managers and decision-makers incorporate OA impacts information into relevant management decisions, prioritize efforts to address these impacts, and determine where to allocate resources to further increase understanding. This workshop brought together managers, policy makers, and scientists to better understand the concept of OA hotspots, ensure it is usable by state decision-makers, and identify key gaps in data and information that inhibit action.

 

Findings from this work may also:

  • Help identify research and data gaps to understanding OA impacts to California’s fishery resources
  • Inform species selection for a modeling exercise to identify species vulnerability thresholds
  • Provide the groundwork for a quantitative OA or climate vulnerability assessment for California or the West Coast

Originally posted: http://www.oceansciencetrust.org/

Dec 28 2018

Global warming today mirrors conditions leading to Earth’s largest extinction event, UW study says

A melting iceberg floats along a fjord leading away from the edge of the Greenland ice sheet near Nuuk, Greenland, in 2011. By this century’s end, if emissions continue at their current pace, humans will have warmed the ocean about 20 percent as much as during the Permian extinction event, newly published research says. (Brennan Linsley / The Associated Press)

 

If humans continue to pump greenhouse gases at our current rate, “we have no reason to think it wouldn’t cause a similar type of extinction,” said Curtis Deutsch, a UW professor and author of the research.

More than two-thirds of life on earth died off some 252 million years ago, in the largest mass extinction event in Earth’s history.

Researchers have long suspected that volcanic eruptions triggered “the Great Dying,” as the end of the Permian geologic period is sometimes called, but exactly how so many creatures died has been something of a mystery.

Now scientists at the University of Washington and Stanford believe their models reveal how so many animals were killed, and they see frightening parallels in the path our planet is on today.

Models of the effects of volcanic greenhouse-gas releases showed the earth warming dramatically and oxygen disappearing from its oceans, leaving many marine animals unable to breathe, according to a study published Thursday in the peer-reviewed journal Science. By the time temperatures peaked, about 80 percent of the oceans’ oxygen, on average, had been depleted. Most marine animals went extinct.

The researchers tested the model’s results against fossil-record patterns from the time of the extinction and found they correlated closely. Although other factors, like ocean acidification, might have contributed some to the Permian extinction, warming and oxygen loss account for the pattern of the dying, according to the research.

By this century’s end, if emissions continue at their current pace, humans will have warmed the ocean about 20 percent as much as during the extinction event, the researchers say. By 2300, that figure could be as high as 50 percent.

“The ultimate, driving change that led to the mass extinction is the same driving change that humans are doing today, which is injecting greenhouse gases into the atmosphere,” said Justin Penn, a UW doctoral student in oceanography and the study’s lead author.

Curtis Deutsch, a UW associate professor of oceanography and an author of the research, said if society continues to pump greenhouse gases at our current rate, “we have no reason to think it wouldn’t cause a similar type of extinction.”

Massive eruptions

The earth 252 million years ago was a much different place. The continents as we know them today were still mostly one landmass, named Pangea, which looks like a chunky letter “C” on a map.

The climate, however, resembled Earth’s now, and researchers believe animals would have adapted many traits, like metabolism, that were similar to creatures today. Nearly every part of the Permian Ocean, before the extinction, was filled with sea life.

“Less than 1 percent of the Permian Ocean was a dead zone — quite similar to today’s ocean,” Deutsch said.

The series of volcanic events in Siberia that many scientists believe set off the mass extinction “makes super volcanoes look like the head of a pin,” said Seth Burgess, a geologist and volcanologist with the United States Geological Survey.

“We’re talking about enough lava erupted onto the surface and intruded into the crust to cover the area of the United States that if you looked at the U.S. from above was maybe a kilometer deep in lava,” he said.

Burgess, who has researched the Siberian Traps volcanic events but did not work on the new Science paper, said scientists believe magma rising from the earth released some extinction-causing greenhouse gases.

In addition, sills of magma still inside the earth heated massive deposits of coal, peat and carbonate minerals, among others, which vented even more carbon and methane into the atmosphere.

“That’s how you drive the Permian mass extinction, by intruding massive volumes of magma into a basin rich in carbon-bearing sediments,” he said.

The UW and Stanford research “takes the next step in figuring out why things died at the end of the Permian,” Burgess said. “It couples what we think was happening in the climate with the fossil record, and it does it elegantly.”

Animals couldn’t breathe

It took a supercomputer more than six months to simulate all the changes the volcanic eruptions are suspected of causing during the Permian period. The computer models go into remarkable detail — simulating things like clouds, ocean currents and marine plant life — in describing what temperatures and conditions were like on Earth.

The researchers knew that surface temperatures rose about 10 degrees Celsius in the tropics because of previous scientific analysis of the fossilized teeth of eel-like creatures called conodonts.

To run their model, researchers pumped volcanic greenhouse gases into their simulation to match temperature conditions at the end of the Permian period.

As temperatures climbed toward the 10-degree mark, the model’s oceans became depleted of oxygen, a trend scientists are evaluating in today’s oceans, too.

To measure how rising temperatures and less oxygen would affect animal species of the Permian period, the researchers used 61 modern creatures — crustaceans, fish, shellfish, corals and sharks. The researchers believe these animals would have similar temperature and oxygen sensitivities to Permian species because the animals adapted to live in similar climates.

Warming’s effects were twofold on the creatures, the researchers found. In warmer waters, animals need more oxygen to perform bodily functions. But warm waters can’t contain as much dissolved oxygen, which means less was available to them.

In other words, as animals’ bodies demanded more oxygen, the ocean’s supply dropped.

In their model, the researchers were able to quantify the loss of habitat as species faced increasingly challenging ocean conditions. Surface-temperature rise and oxygen loss were more substantial in areas farther from the equator. Extinction rates also increased at higher latitudes.

Animals in the tropics were already accustomed to warmer temperatures and lower oxygen levels before the volcanic eruptions shifted the climate, according to the research. As the world warmed, they could move along with their habitat.

Marine creatures that favored cold waters and high oxygen levels fared worse: They had nowhere to go.

“The high latitudes where it’s cold and oxygen is high — if you’re an organism that needs those kind of conditions to survive, those conditions completely disappear from Earth,” Deutsch said.

In modern oceans, warming and oxygen loss have also been more pronounced near the poles, researchers said, drawing another analogue between the shift in climate some 252 million years ago and what’s happening today.

“The study tells us what’s at the end of the road if we let climate [change] keep going. The further we go, the more species we’re likely to lose,” Deutsch said. “That’s frightening. The loss of species is irreversible.”


Original post: https://www.seattletimes.com/

Evan Bush: 206-464-2253 or ebush@seattletimes.com; on Twitter: @EvanBush.

Dec 2 2018

‘Get the balance back’: Amid seal and sea lion boom, group calls for hunt on B.C. coast

Quickest way to reverse declining salmon stocks is to introduce a harvest: Pacific Balance Pinnipeds Society

Greg Rasmussen · CBC News · Posted: Dec 01, 2018 1:00 AM PT

For the first time in decades, a small-scale seal hunt is taking place on Canada’s West Coast — all in the hopes that it leads to the establishment of a commercial industry to help control booming seal and sea lion populations and protect the region’s fish stocks.

In early November, a group called the Pacific Balance Pinnipeds Society (PBPS) started using First Nations hunting rights as part of a plan to harvest 30 seals. The society plans to test the meat and blubber to see if it’s fit for human consumption and other uses.

“We can look at opening up harvesting and starting a new industry,” said Tom Sewid, the society’s director and a commercial fisherman. “Since the [West Coast] seal cull ended in the 1970s, the population has exploded.”

Sewid, who is a member of the Kwakwaka’wakw First Nation, points out that Indigenous people have hunted the animals for thousands of years. Recent decades with little or no hunting have been an anomaly, he said, pointing to research that shows seal numbers are even higher now than in the 1800s.

Out go the nets, in come the sea lions

What’s become an ongoing battle between humans and sea lions played out on a recent nighttime fishing expedition, when Sewid and a crew of commercial fishermen set out in a 24-metre seine boat to fish for herring off the coast of Parksville, B.C.

The crew’s goal was to catch about 100 tonnes of herring, which rise to the surface to feed after dark. But the faint barking of sea lions was soon heard over the thrum of the boat’s diesel engine.

“All them sea lions out there are all happy — [they’re] all yelling, ‘Yahoo, it’s dinner time!'” Sewid said.

Once the crew spotted the herring, they let out hundreds of metres of net, while a smaller boat helped to circle it around the huge mass of fish. The crew then closed the bottom of the net, capturing the herring.

 

Watch sea lions pillage fishermen’s nets:

Many Sea Lions are caught in fishing nets, as they try to feed. 0:27

 

But the catch also provided some uninvited visitors with a captive dinner: Dozens of sea lions jumped over the floats holding up the net and started to gorge.

“These guys, it’s just a buffet for them,” said Sewid, as the bodies of the sea lions glistened in the boat’s floodlights. “Just like pigs at a trough.”

Sewid said the sea lions have learned there’s an easy meal to be had whenever they see or hear the fishing boats.

“They’re not afraid of us. They’ve habituated themselves to seeing that humans and fishing equates easy access to food, which is not right,” he said. “The animal kingdom is not supposed to be like that.”

Restarting a banned hunt

The hunting of seals and sea lions — which are collectively known as pinnipeds — has been banned on the West Coast for more than 40 years. It’s one reason their numbers have exploded along the entire Pacific coastline of North America.

According to one study, the harbour seal population in the Salish Sea is estimated at 80,000 today, up from 8,600 in 1975. The study also says seals and sea lions now eat six times as many chinook salmon as are caught in the region’s commercial and sports fisheries combined.

That adds up to millions of tonnes of commercially valuable fish.

Sewid’s group is proposing to cull current populations of harbour seals and sea lions by half, which would see thousands of the animals killed each year.

Tom Sewid is leading the effort to secure what he calls a sustainable harvest of seals and sea lions along the B.C. coast. (Greg Rasmussen/CBC)

The society’s small-scale “test” harvest is taking place between B.C.’s southern Gulf Islands and as far north as Campbell River, on Vancouver Island. It’s being carried out under the provisions of the Aboriginal Fisheries Strategy, which gives some First Nations harvesting and management rights for food and ceremonial purposes.

Testing the meat to see if it’s safe for human consumption is a first step in a plan to eventually gain permission for what the PBPS envisions as a sustainable, humane commercial hunt, which would largely be carried out by coastal First Nations.

“All the meat that’s in there, you’re looking at the high-end restaurants [that would sell it],” Sewid said. “The hides can also be used.”

Seal blubber is particularly valuable, he said, because it can be rendered down into an oil that’s in demand because of its high Omega-3 fatty acid content.

 

Watch fishing crew struggle to free sea lions entangled in their nets:

Watch as fishing crew struggles to free sea lions trapped in their nets. 0:49

 

One of the biggest hurdles facing the group is convincing the federal Department of Fisheries and Oceans to open a commercial hunt on the West Coast.

The seal hunt that takes place in the Atlantic and Arctic is controversial, and has long been subject to protests and fierce opposition from animal rights groups. The group expects a West Coast harvest to also face fierce confrontations.

Canadian Inuit have been waging a counter-campaign, highlighting the importance of the animal and the longstanding tradition of their hunt.

Most Canadian seal products are also banned in Europe and a handful of other countries, but the society says demand is strong in Asia.

Supporters and opponents

The PBPS does have a growing list of supporters, including 110 First Nations groups, a number of commercial fishing organizations, and some sectors of B.C.’s economically important sport fishing sector.

However, one key player, the Sport Fishing Institute of B.C., opposes a large commercial hunt, fearing it would generate public outrage and might not achieve the goal of enhancing fish stocks.

The institute’s director, Martin Paish, says the group sees some value in targeting some seals and other fish predators at specific times of year in a number of key river systems; he believes a limited hunt would help protect salmon stocks and boost the billion-dollar-a-year B.C. sport fishing industry.

“Our goal is to use predator control in a careful manner to improve chinook [salmon] production where it is needed,” said Paish.

Carl Walters is a fish biologist and UBC professor who supports cutting B.C.’s population of seals and sea lions by half. (Nic Amaya/CBC)

Fisheries scientist Carl Walters, a professor emeritus with UBC, believes culling the regions sea lions and seals could dramatically boost salmon stocks. He points to numerous studies showing how pinniped populations have been increasing, while salmon numbers have been plummeting.

“They’re killing a really high percentage of the small salmon shortly after they go into the ocean, about half of the coho smolts and a third of the chinooks,” he said.

Advocates of a hunt are also pitching it as a way to help B.C.’s endangered southern resident killer whales, which feed mainly on salmon.

“The thing that would benefit southern resident killer whales is to see improved survival of small chinook salmon — and I think the only way we can achieve that is by reducing seal numbers,” Walters said.

Peter Ross, from the Coastal Ocean Research Institute, says there would be little benefit to salmon from a seal and sea lion cull. (Nic Amaya/CBC)

Others disagree, including Peter Ross, the vice-president of research and executive director of the Coastal Ocean Research Institute.

“Killing of seals and sea lions is not going to have any positive impact for any salmon populations in coastal British Columbia,” he said.

While a few localized populations of salmon might benefit from a cull, Ross said climate change, habitat destruction and overfishing are all bigger factors in the overall decline of stocks.

Other subspecies of orcas, however, feed mainly on seals, so a hunt would reduce their access to prey.

Back on the boat, Sewid concedes a hunt would be controversial — but he firmly believes it’s necessary.

“All the indicators are there,” he said. “It’s time to get the balance back.”

The fishing crew from the Western Investor are shown harvesting herring in November. But they say they are being hampered by dozens of sea lions in their nets almost every night. (Nic Amaya/CBC)


Original post: https://www.cbc.ca/news/canada/british-columbia/seal-hunt-b-c-1.4921610

Nov 11 2018

Major Disease Outbreak Strikes California Sea Lions

preamble —

This article stated:  The National Oceanic and Atmospheric Administration announced in January that California sea lions had reached carrying capacity—the number of individuals their environment can sustainably support—in 2008.

The expected symptoms of a population of mammals at carrying capacity include reduced reproductive output, decreased growth and survival of young animals, delayed sexual maturity, increases in disease or parasites and decreased size and survival of adults.   There have beenrecent increases in California sea lion pup mortality and reduced pup growth rates, as well as increased incidence of leptospirosis observed in central California and Oregon, leading to the suggestion that the population is approaching carrying capacity (McClatchieet al. 2016).


Leptospirosis afflicts sea lions on a semi-regular cycle, but warming waters and migrating fish could make the marine mammals more susceptible

Princepajaro, a male California sea lion, swims in a pool during treatment for leptospirosis at The Marine Mammal Center in Sausalito, CA. When a leptospirosis outbreak occurs, the Center’s scientists study the disease to learn more about what causes an outbreak and how we can improve treatment for infected animals. (Bill Hunnewell / The Marine Mammal Center)

Shawn Johnson knew it was coming.

“Last fall, we saw a few cases,” he said. “And that was a warning signal, so we were prepared—well, we weren’t prepared for this level of an outbreak.”

Over the past month, Johnson, director of veterinary science at the Marine Mammal Center, just north of San Francisco, and his team have been getting an average of five sick California sea lions a day. The animals have leptospirosis, a bacterial infection that affects their kidneys, causing fatigue, abdominal pain and, more often than not, death.

As of October 16, Johnson’s team had seen 220 sea lions with the disease, which made it the center’s second largest outbreak. Since then, the center reported 29 more sea lions have been rescued and 10 of those died due to leptospirosis. More than a dozen animals are still awaiting diagnosis. The number of cases has started to slow, but if historical trends hold up, Johnson expects this outbreak to eventually surpass 2004’s record of 304 cases of sea lion leptospirosis.

The Marine Mammal Center in Sausalito, CA, is responding to an outbreak of a potentially fatal bacterial infection called leptospirosis in California sea lions. The pictured sea lion, Glazer, is seen curled up with his flippers folded tightly over his abdomen prior to his rescue by trained Center responders in Monterey. The posture exhibited is known as “lepto pose,” and is often an indication the sea lion is suffering the effects of the disease. (The Marine Mammal Center)

 

All told, about 70 percent of the sea lions the team tried to save have died.

Leptospirosis outbreaks among sea lions occur at fairly regular intervals, but changing ocean conditions—warmer waters and relocating fish—are affecting how the disease strikes populations along the Pacific Coast. The threats aren’t new, but they’re threatening in slightly new ways. Changes in marine conditions appear to be affecting the population’s resiliency to this disease and others. While researchers scramble to save sick sea lions today, they are also studying what this year’s outbreak can tell us about how sea lions will fare down the line.

The good news is that sea lions are fairly mobile and resilient animals. And until recently, their populations were booming. The National Oceanic and Atmospheric Administration announced in January that California sea lions had reached carrying capacity—the number of individuals their environment can sustainably support—in 2008.

Since then, though, their numbers have fluctuated. A “blob” of unusually warm and long-lasting water moved in along the West Coast from 2013 to 2015, causing widespread algal blooms that spread a neurotoxin called domoic acid throughout the marine food chain. Sea lions with elevated levels of the toxin suffered brain damage, resulting in strokes and an impaired ability to navigate, ultimately killing most of the afflicted individuals.

The warm water also sent fish and smaller marine life out to search for cooler environments, meaning the sea lions had to travel farther to find food. The combination of more distant hunting and impaired navigation led to record numbers of stranded pups—many taken in by the Marine Mammal Center—as well as a dip in the sea lion population during those years.

California sea lion Yakshack is one of 220 patients at The Marine Mammal Center in Sausalito, CA, that has been rescued so far this year impacted by a bacterial disease known as leptospirosis. The Center has been at the forefront of research on leptospirosis in marine mammals and has published a number of scientific papers on the disease dating back to 1985. (Bill Hunnewell / The Marine Mammal Center)

 

But the warm water conditions also led, ironically, to a decline in cases of leptospirosis during that time. Over the past decade, scientists have determined that the disease, which spreads via a parasite, is endemic to the population. Some animals carry the disease and don’t get sick, but they do excrete the parasites in their urine, which is how it spreads to other individuals. When sea lions haul out on a pier or beach, they freely roll around in each other’s pee.

When the blob of warm water appeared, sea lions had to swim farther to find food and had less time to haul out and be social, Johnson says, meaning less time sitting around in each other’s pee and parasites—and fewer cases of leptospirosis. But the lack of the disease a few years ago led to consequences today. Sea lions that get leptospirosis and survive develop antibodies that fend off the parasite in the future, says Katie Prager, a veterinarian researcher at UCLA’s Lloyd-Smith Laboratory who collaborates with the Marine Mammal Center. These antibodies, however, cannot be inherited by offspring.

“It’s not something that can be passed on,” Prager says. “Antibodies are something that the pup has to develop on its own.”

The warm waters meant fewer sick sea lions, but it left the population very vulnerable. Now the disease is back with a vengeance.

“A lot of the animals are now naive to that bacteria and their immune systems haven’t been exposed to that,” says Alissa Deming, a veterinarian researcher at Dauphin Island Sea Lab in Alabama who previously studied sea lion diseases at the Marine Mammal Research Center. “There is a group of animals that haven’t seen this before.”

The risk, according to the researchers, is that continued domoic acid outbreaks could result in a vicious cycle—fewer cases of leptospirosis produce unexposed populations, and then major outbreaks flare up like we are seeing this year.

“This is a great example of how environmental change has so much impact on a wild species—all the way from where they eat, where they migrate and how their diseases change over time, just based on a few degrees’ increase,” Johnson says.

California sea lion Herbie lays on his pen floor during treatment for leptospirosis at The Marine Mammal Center in Sausalito, CA. Veterinarians can usually identify leptospirosis in a patient even before laboratory tests confirm a diagnosis because of the infection’s distinctive symptoms in California sea lions, which include drinking water and folding the flippers over the abdomen. (Bill Hunnewell / The Marine Mammal Center)

 

The first documented case of a marine mammal suffering from the domoic acid toxin was in 1998, and the events are now increasing in frequency—so much so that the spread of domoic acid has become a yearly sign of the changing seasons around San Francisco Bay. “The days are getting shorter, pumpkin spice lattes are here and once again, it’s time for that other Bay Area rite of fall: worrying about the levels of toxins in local Dungeness crabs,” begins a recent San Francisco Chronicle article on the influence of the toxin on the start of crabbing season.

Sea lions don’t wait for permission from the Department of Public Health before they start eating crabs, though.

To exacerbate the issue even more, an El Nino event is predicted over the coming months, meaning warmer ocean waters off the West Coast and possibly more algal blooms and toxins. Already, Southern California waters—where researchers have found some of the highest concentrations of diatoms that produce domoic acid—have had record high temperatures this year.

NOAA has even deemed the recent warm-water years a “climate change stress test” for West Coast oceans. The agency said the conditions “may offer previews of anthropogenic climate change impacts projected for the latter part of the 21st century.”

If this has been a test, sea lions might not have passed, says Robert DeLong, a scientist with NOAA’s Alaska Fisheries Science Center. DeLong has been studying California sea lions for decades at their breeding grounds, Channel Islands off Santa Barbara. He says the species should be pretty resilient in the face of climate change, but the rate of warming waters is proving a major challenge.

Volunteers from The Marine Mammal Center in Sausalito, CA, release California sea lions Bogo (left), Brielle (center), and Biggie (right) back to the wild near Bodega Bay. All three sea lions were treated for leptospirosis at the Center’s Sausalito hospital. Many different animal species, including humans and dogs, can become infected with Leptospira through contact with contaminated urine, water or soil. The Center has a number of safety protocols in place to prevent transmission to veterinarians and volunteers working with sea lion patients. (Bill Hunnewell / The Marine Mammal Center)

 

The center of the West Coast sea lion population is around Baja California, so the species has adapted to warmer water than is currently being seen farther north up the coast. “They have that capability to live in warmer water,” DeLong says. And unlike, say, coral reefs, sea lions are very mobile, able to swim long distances to find suitable habitats.

But while males can chase food far up north, during the breeding season females are tied to a small radius around the rookery. If there is less food available there because fish have moved to cooler waters, it could present a major problem for sea lion mothers and their pups.

“So if this is what climate change looks like, and this period is an adequate proxy, if that’s really the case, then sea lions may not do as well as we would think,” DeLong says.

There are still signs of hope. Sea lions are increasingly moving north to new breeding grounds off the San Francisco Bay, for instance. The limiting factor is time.

“If the environmental changes are slow enough to adapt, they’ll be able to move and will probably move farther up the coast,” Johnson said. “If changes are slow enough, I could see them being able to adapt.”


Original post: https://www.smithsonianmag.com/

 

Nov 8 2018

Quantifying sensitivity and adaptive capacity of shellfish in the Northern California Current Ecosystem to increasing prevalence of ocean acidification and hypoxia

The severity of carbonate chemistry changes from ocean acidification is predicted to increase greatly in the coming decades, with serious consequences for marine species-­ especially those reliant on calcium carbonate for structure and function (Fabry et al. 2008). The Northern California Current Ecosystem off the coast of US West Coast experiences seasonal variations in upwelling and downwelling patterns creating natural episodes of hypoxia and calcite/aragonite undersaturation, exacerbating global trends of increasing ocean acidification and hypoxia (OAH) (Chan et al. 2008) (Gruber et al. 2012). The goal of these experiments was to identify thresholds of tolerance and attempt to quantify a point at which variance in responses to stress collapses. This study focuses on two species: Cancer magister (Dungeness crab) and Haliotis rufescens (red abalone). These species were selected for this study based on their economic and ecological value, as well as their taxonomic differences. Respirometry was used as a proxy for metabolic activity at four different scenarios mimicking preindustrial, upwelling, contemporary upwelling, and distant future conditions by manipulating dissolved oxygen and inorganic carbon (DIC) concentrations. Both species showed a decrease in mean respiration rate as OAH stressors increase, including an effect in contemporary upwelling conditions. These results suggest that current exposure to ocean acidification (OA) and hypoxia do not confer resilience to these stressors for either taxa. In teasing apart the effects of OAH as multiple stressors, it was found that Dungeness crab response was more strongly driven by concentration of dissolved oxygen, while red abalone data suggested a strong interactive effect between OA and hypoxia. Not only did these two different taxa exhibit different responses to a multiple stressors, but the fact that the Dungeness crab were secondarily impacted by acidification could suggest that current management concerns may need to be focus more strongly on deoxygenation.

Gossner H. M., 2018. Quantifying sensitivity and adaptive capacity of shellfish in the northern California current ecosystem to increasing prevalence of ocean acidification and hypoxia. MSc thesis, Oregon State University, 104 p. Thesis.


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

Nov 8 2018

Alterations to seabed raise fears for future

The ocean floor as we know it is dissolving rapidly as a result of human activity.

Normally the deep sea bottom is a chalky white. It’s composed, to a large extent, of the mineral calcite (CaCO3) formed from the skeletons and shells of many planktonic organisms and corals. The seafloor plays a crucial role in controlling the degree of ocean acidification. The dissolution of calcite neutralizes the acidity of the CO2, and in the process prevents seawater from becoming too acidic. But these days, at least in certain hotspots such as the Northern Atlantic and the southern Oceans, the ocean’s chalky bed is becoming more of a murky brown. As a result of human activities the level of CO2 in the water is so high, and the water is so acidic, that the calcite is simply being dissolved.

The McGill-led research team who published their results this week in a study in PNAS believe that what they are seeing today is only a foretaste of the way that the ocean floor will most likely be affected in future.

Long-lasting repercussions

“Because it takes decades or even centuries for CO2 to drop down to the bottom of the ocean, almost all the CO2 created through human activity is still at the surface. But in the future, it will invade the deep-ocean, spread above the ocean floor and cause even more calcite particles at the seafloor to dissolve,” says lead author Olivier Sulpis who is working on his PhD in McGill’s Dept. of Earth and Planetary Sciences. “The rate at which CO2 is currently being emitted into the atmosphere is exceptionally high in Earth’s history, faster than at any period since at least the extinction of the dinosaurs. And at a much faster rate than the natural mechanisms in the ocean can deal with, so it raises worries about the levels of ocean acidification in future.”

In future work, the researchers plan to look at how this deep ocean bed dissolution is likely to evolve over the coming centuries, under various potential future CO2 emission scenarios. They believe that it is critical for scientists and policy makers to develop accurate estimates of how marine ecosystems will be affected, over the long-term, by acidification caused by humans.

How the work was done

Because it is difficult and expensive to obtain measurements in the deep-sea, the researchers created a set of seafloor-like microenvironments in the laboratory, reproducing abyssal bottom currents, seawater temperature and chemistry as well as sediment compositions. These experiments helped them to understand what controls the dissolution of calcite in marine sediments and allowed them to quantify precisely its dissolution rate as a function of various environmental variables. By comparing pre-industrial and modern seafloor dissolution rates, they were able to extract the anthropogenic fraction of the total dissolution rates.

The speed estimates for ocean-bottom currents came from a high-resolution ocean model developed by University of Michigan physical oceanographer Brian Arbic and a former postdoctoral fellow in his laboratory, David Trossman, who is now a research associate at the University of Texas-Austin.

“When David and I developed these simulations, applications to the dissolution of geological material at the bottom of the oceans were far from our minds. It just goes to show you that scientific research can sometimes take unexpected detours and pay unexpected dividends,” said Arbic, an associate professor in the University of Michigan Department of Earth and Environmental Sciences.

Trossman adds: “Just as climate change isn’t just about polar bears, ocean acidification isn’t just about coral reefs. Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth’s climate history.”

“This study shows that human activities are dissolving the geological record at the bottom of the ocean,” says Arbic. “This is important because the geological record provides evidence for natural and anthropogenic changes.”

McGill University (via SienceDaily), 29 October 2018. Article.


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

Oct 29 2018

Coastal Pacific Oxygen Levels Now Plummet Once A Year

40-year crabber David Bailey says hypoxic water can show up like the flip of a switch, “If there are crabs in the pot, they’re dead. Straight up.” — Kristian Foden-Vencil/Oregon Public Broadcasting

 

Scientists say West Coast waters now have a hypoxia season, or dead-zone season, just like the wildfire season.

Hypoxia is a condition in which the ocean water close to the seafloor has such low levels of dissolved oxygen that the organisms living down there die.

Crabber David Bailey, who skippers the Morningstar II, is rattled by the news. He remembers a hypoxia event out of Newport, Oregon, about a decade ago. He says it shows up “like a flip of a switch.”

“It shows up like a flip of a switch,” he says.

“If there are crabs in the pot, they’re dead. Straight up,” Bailey says. And if you re-bait the pots, “when you go out the next time, they’re blanks, they’re absolutely empty. The crabs have left the area.”

A hypoxia event will kill everything that can’t swim away—animals like crabs, sea cucumbers and sea stars.

“We can now say that Oregon has a hypoxia season much like the wildfire season,” says Francis Chan, co-chair of the California Hypoxia Science Task Force.

“Every summer we live on the knife’s edge and during many years we cross the threshold into danger – including the past two years,” Chan says. “When oxygen levels get low enough, many marine organisms who are place-bound, or cannot move away rapidly enough, die of oxygen starvation.”

The hypoxia season hits Oregon, Washington and California waters in the summer and can last from a few of days to a couple of months. Some years it only affects a few square miles of ocean; other years it’s thousands of square miles.

Video taken by the Oregon Department of Fish and Wildlife in 2006 showed dead marine life littering the sea floor.

“These reefs that used to be full of rockfish, they were all gone and a lot of the marine life: the sea stars, the sea cucumbers. They were dead,” says Chan.

The question now is: Why is this happening?

“One of the more fundamental reasons is that the ocean is warmer now and warmer water holds less oxygen,” says Chan. “And then the second part is that a warmer surface ocean, it acts as an insulating blanket.”

So that blanket stops colder low-oxygen water from rising up and mixing with oxygen in the surf.

Scientists say climate change is behind this. The ocean has been absorbing nearly all the rising heat from greenhouse gas emissions, and it’s projected to grow even warmer in coming decades.

Other factors may be contributing too. Oregon State University oceanographer and co-chair of the Oregon Coordinating Council on Ocean Acidification and Hypoxia Jack Barth, thinks higher temperatures are also slowing ocean currents. If we could see under the waves, he says, there’d be a lot more concern.

Oregon State University oceanographer Jack Barth deploys a glider that will spend weeks at sea collecting data on everything from dissolved oxygen levels to temperature. “When we used to think about hypoxia in the ocean, we think about little areas. But now what we’re looking at is…out in the ocean, there’s low oxygen…all along the coast,” he says.

Kristian Foden-Vencil/Oregon Public Broadcasting

“As an analogy, think about the summer when the skies were filled with smoke. Covered the whole Pacific Northwest,” Barth says. “When we used to think about hypoxia in the ocean, we think about little areas. But now what we’re looking at is…low oxygen all along the coast.”

Barth is collecting data to draw the first hypoxia maps of Oregon’s coast.

“We’re actually seeing real interest from the fishing community. They know how to look at our data and say, ‘Where are the layers in the ocean? Where is the high and low oxygen?'” Barth says.

Barth also notes that the crabbing and the oyster industries were ahead of the curve. “They were among the first to notice that the ocean just off our coast is changing and was affecting their livelihoods,” Barth says. “And they have been working with scientists ever since.”

Deep Pacific waters 50 miles off the coast have always been hypoxic. And it’s hardly surprising. The water down there take decades to slowly flow thousands of miles from Japan to the west coast — all the while separated from oxygen in the air.

But in 2002, fishers started to notice hypoxic waters moving closer-in — to just a couple of miles off the coast.

Back then, Francis Chan had just finished his Ph.D and was looking for a research subject. State fish and wildlife biologists started to call him to say crabbers were calling them, saying their crabs were dead. The crabbers also noticed strange behavior, like octopuses climbing up ropes.

Chan went out to sample the water and found extremely low levels of dissolved oxygen across tens of square miles. Four years later it happened again, but across a larger area and with lower oxygen levels.

“Hypoxia is something we rarely saw throughout the 20th century,” Chan says, “but have seen almost annually since the year 2002.”

The National Oceanic and Atmospheric Administration just issued a grant for about 40 new oxygen sensors to be distributed among crabbers so they gather data where they put their pots. Crabbers say they’re happy to hand over the data, but they’re not so sure about revealing the locations — favorite crabbing spots are a closely held secret.


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

Sep 26 2018

Sardines

The little things

Consider the sardine. The small fish sits at the base of the ocean’s food web. Cold currents welling up in the Pacific and Atlantic oceans nurture schools of billions of the creatures, their populations waxing and waning in decades-long global cycles. Entire industries and ecosystems have been built upon the little swimmers.

Not that they get much credit. Sardines are ground up into animal meal, rendered into oil or bait, and stuffed unceremoniously into cans for mass consumption.

But their star is on the rise. Trendy, delicious, and aesthetically irresistible, sardines have begun to garner public adoration once again. In Portugal, the city-wide celebration of Santo António, Lisbon’s patron saint, wouldn’t be complete without a fresh sardine, grilled on a street corner with a splash of lemon. In fact, Portugal has elevated the sardine to the pinnacle of its culinary culture, prizing them equally at home or on a white tablecloth. And finally, the rest of the world is catching on.

But just as they’re ready to swim back into our lives again, the fish may be leaving for cooler waters. Climate change is threatening the species’ ancestral homes. Let’s dive in.

By the digits

300 AD: Date to which scientists have ocean sediment cores tracking population fluctuations of Pacific sardines

30 years: Age at which canned sardines are still excellent to eat

7 km (4.3 miles): Length of shoals of fish in the South African sardine run, which rivals in biomass East Africa’s great wildebeest migration

0.323 kg (0.71 lb): Weight of the heaviest sardine on record

15 years: Oldest recorded age of a live sardine

Sardine populations have been rising and falling for thousands of years. An average cycle is approximately 55-60 years. But combination of overfishing in some regions and natural cycles means catches have been falling since the 1990s.

 

Wait, what’s a sardine again?

Sardines are not just one, but at least 21 species of cold-water loving fish. Silds, sprats, herring and pilchards are all classified as sardines, depending on whether one is fishing in the Mediterranean, North Sea, Pacific or elsewhere.

Sardines live fast, but they don’t die young. The oldest can live for 15 years, reaching 90% of their adult length (about 27 cm) within a year. They swim with their mouths open, gorging on tiny phytoplankton and zooplankton in the water column. Within a few years, females can spawn 400,000 to 1 million eggs annually (to match their fecundity, hens would need to lay almost 5,000 eggs.)

That’s good news, because sardines are the all-you-can-eat buffet of the sea. They are the key forage species for predators including fish, squid, marine mammals, and seabirds. Not to mention humans: Fishery experts estimate every major sardine fishery in the world is already fully exploited.

Reuters/Lucy Nicholson

 

The fish that filled a thousand factories

The ancient Greeks and Romans loved sardines, and the first modern sardine factory opened in Setúbal, Portugal in 1880. The country is the fish’s greatest champion on the continent, and celebrates St. Anthony’s Day (June 13th) by grilling fresh sardines on every street corner.

Sardines are typically washed, cleaned, and steamed before being packed in oil or water. Styles vary. Olive oil is preferred in Portugal, Spain, and Morocco. Soybean oil is common in the US, herring oil in Norway, while some prefer water, mustard or tomato sauce. Sardine scales are suctioned off to make cosmetics, lacquers, and artificial pearls.

Today the industry is almost gone from the US. The value of sardines consumed once routinely exceeded that of Maine lobsters in the 1960s. But by 2005, per capita sardine consumption had fallen to 0.1 pounds per year in the US (compared to 16 pounds for all seafood and 220 pounds of meat), and has yet to recover. California’s famed canneries, immortalized in John Steinbeck’s Cannery Row, declined from about 51 in 1948 to just one in 1968—today there are zero. Maine’s last cannery closed in 2010.

Reuters/Nacho Doce

How do I eat them?

Sardines were once considered finer than lobster. Oscar Wilde’s son even opened a sardine tasting club in 1930s London. The finest specimens ended up in European pantries next to foie gras and caviar.

Demand for protein during WWII transformed them into lunchbox food for workers and soldiers in the US, takng the shine off the species’ reputation. Human consumption has been declining ever since.

But all is not lost. A cadre of “sardinistas” around the world are resurrecting the culinary glory days of the sardine. (They happen to be great for you: full of protein, essential fats, and amino acids, vitamins, and minerals.)

The classic preparation is to grill up fresh sardines rubbed with olive oil, garlic, and parsley and splash on a bit of red wine vinegar and lemon juice. There’s also sardelosalata, a version of a classic caviar, and no shortage of inventive things to do with the canned ones.

Staying out of hot water

Sardines may not be sticking around. Stocks have recently plummeted by almost 80% off the coast of Portugal and Spain, grounding their fleets for months (a 15-year ban is being contemplated). The US just shut down the west coast sardine fishery for the fourth straight year after a 97% collapse in sardine populations since 2006.

The reason? Natural cycles in the oceans, for the most part. But now global warming is set to take over. As soon as ocean temperatures rise above sardines’ preferred 10 to 15°C, they leave, says Francisco Chavez, a biological oceanographer at the Monterey Bay Aquarium Research Institute.

For now, natural cycles are the primary factory in sardines’ boom and bust cycles. “It’s not going to be that way in the future,” Chavez says. “In maybe 20 years, climate change will be the dominant player.” When that happens, sardines will head to the poles, leaving their traditional fishing grounds, and the countries that rely on them, high and dry.

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Original post: https://qz.com/emails/quartz-obsession/1400071/