Ocean Action Hub

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Ocean Acidification Is Frying Fish’s Sense of Smell

9 Aug 2018 - By the end of the century, the ocean is predicted to become two-and-a-half times more acidic, which is bad news for sea life.

9 Aug 2018 - It’s hard to imagine since our sense of smell pretty much disappears underwater, but fish rely heavily on their sniffers to detect predators, find food and locate mates. Lina Zelovich at JSTOR Daily reports that for some fish, that critical sense is being dulled as the acidity of the ocean increases. And with climate change making the seas even more acidic each year, the problem is set to get worse.

The ocean is a pretty good carbon sink, capturing about a quarter of all the CO2 released by humans. While that’s a good thing for slowing climate change, it has big consequences for the ocean ecosystem. Over the last two centuries, the extra CO2 humanity has pumped into the atmosphere has increased ocean acidity by 43 percent. It’s estimated that by 2100 the ocean could be 2.5 times more acidic than it is now.

The carbon dioxide that the sea absorbs undergoes a chemical reaction with the water to create carbonic acid in a process known as ocean acidification. Though the acid is weak, it’s plentiful enough to cause problems, like disrupting the formation of shells in many marine species. An international team of researchers explored the impact ocean acidification has on fish in a new study published this week in the journal Nature Climate Change.

The researchers first looked at juvenile European sea bass, Dicentrarchus labrax, in ocean water with normal carbonic acid levels. Then they examined the fish in water mimicking the acid levels expected by the end of the century. The differences in behavior were striking. The fish swam less and were more likely to “freeze” for five seconds or more, a sign of fishy anxiety. Most importantly, to smell something they had to get much, much closer to it—not the best move if the source of the scent is a potential threat.

“The sense of smell of sea bass was reduced by up to half in sea water that was acidified with a level of CO2 predicted for the end of the century. Their ability to detect and respond to some odors associated with food and threatening situations was more strongly affected than for other odors,” says the study’s lead author Cosima Porteus, a fish physiologist at the University of Exeter in the United Kingdom. “We think this is explained by acidified water affecting how odorant molecules bind to olfactory receptors in the fish’s nose, reducing how well they can distinguish these important stimuli.”

Many animals have genetic resources to help them overcome times of change or stress, like developing more sensory receptors. The researchers wanted to see if the fish might have a toolbox of genes they could use to help them overcome the loss of smell, but nothing of the sort was found.

“One way to smell something better is to have more receptors detecting these smells in order to increase the chance that particular smell will be detected, and therefore increase the expression of these receptors,” Porteus tells Marlene Cimons at Popular Science. “Another way is [for them] to make a slightly different receptor that works better under lower pH. However, we did not find any evidence this was the case.”

In fact, the acid-washed fish produced fewer smell receptors, making it even more difficult for them to detect odors.

It’s likely that acidification won’t just impact sea bass. Porteus says the results should apply to almost all fish including cod, salmon, haddock and other economically important species and may apply to marine invertebrates like lobster as well.

In the next phase, the team will compare the acid levels in today’s ocean to preindustrial times to determine whether fish are already experiencing significant problems with their sniffers. The solution to the problem, like it is for a myriad of problems facing the world, is to tackle carbon emissions head on, whether we can smell them or not.

CONTINUE READING: https://www.smithsonianmag.com/smart-news/ocean-acidification-frying-fis...

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Why the Ocean Needs Wilderness

6 Aug 2018 - A new study finds that only 13 percent of the ocean can be classified as “wilderness.” But what does this even mean?

6 Aug 2018 - Anyone who’s ventured beyond the sight of land or looked down from a jetliner could easily imagine most of the vast ocean as a wilderness, a place that human influence could barely reach, even if we tried. But that is definitely not the case. The impact of human activity on the ocean is pervasive, deep and on the rise. Industrial fishing has reduced fish stocks in coastal waters and in every corner of the high seas; shipping lanes wrap around the globe; agricultural runoff and industrial pollution are impacting coral reefs and creating dead zones; drilling rigs dot coastal shelves; and microplastics are everywhere. A new industry of seafloor mining will likely begin in the near future. And that’s not to mention the impacts of climate change, which are rearranging marine habitats and acidifying the oceans.

But it turns out, there are still some spots left in the ocean that have seen minimal human interference, areas that might be dubbed “wilderness.” Though those areas are disappearing rapidly, they are more important than ever; studies show that areas with minimal human impact are the biological engines of the ocean, preserving biological diversity, acting as breeding grounds for fish stocks and bastions of resilience in our rapidly transforming oceans. Deciding what, exactly, constitutes a wilderness in the ocean, however, is not completely figured out, though some researchers are trying to find an answer.

Wilderness, in the broadest definition of the term, simply means an area uninhabited by humans that is more or less in its natural state. Over the last century, at least in the United States, it’s taken on a legal definition. The 1964 Wilderness Act created a legal designation that keeps some remarkable public lands as untouched as possible. Unlike National Parks, with their visitor centers and traffic-clogged roads, or National Forests, which can sell off tracts of timber and are crisscrossed by logging roads, wilderness areas (most of which are in remote sections of National Parks and Forests) have no roads or concession stands, just footpaths. Most can only be visited on foot, horseback or canoe with off-road vehicles and even bicycles banned. The logic behind the Wilderness Act, though it is still debated, continues to make sense 50 years after its passage—the world needs areas and ecosystems that function without the influence of humans, not only to protect plants and animals, but to give humans the possibility of experiencing a world without Facebook.

It’s relatively easy to look on a map and decide which large tracts of undeveloped forest or desert should be wilderness. But it’s much harder to stare at the ocean and make the same decision. That’s why Kendall Jones of the University of Queensland and colleagues from the Wilderness Conservation Society decided to take a stab at coming up with criteria to identify ocean wilderness. The team looked at global data from 19 human-induced stressors on the ocean to develop a map of wilderness, or areas least affected by us. The threats include different types of fishing, commercial shipping, invasive species and nutrient, light and industrial pollution. When they are all rolled together the team found that just 13 percent of the world’s oceans fit their definition of wilderness. The vast majority of those wild areas are found near the poles and in a portion of the South Pacific. The North Atlantic has no wilderness left at all. If the impacts of climate change, including temperature increases, acidification and other effects, are rolled into the equation, Jones explains, there is simply no wilderness left anywhere. The research appears in the journal Current Biology.

CONTINUE READING: https://www.smithsonianmag.com/science-nature/why-ocean-needs-wilderness...

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Chile Announces Protections for Massive Swath of Ocean With Three New Marine Parks

28 Feb 2018 - The almost 450,000 square miles encompass a stunning diversity of marine life, including hundreds of species found nowhere else.

28 Feb 2018 - Chile’s President Michelle Bachelet signed into law protections for nearly 450,000 square miles of water—an area roughly the size of Texas, California and West Virginia combined. Split into three regions, the newly protected areas encompass a stunning range of marine environments, from the spawning grounds of fish to the migratory paths of humpback whales to the nesting grounds of seabirds.

“The Chilean government has really positioned itself as a global leader in ocean protection and conservation,” says Emily Owen, an officer with Pew Bertarelli Ocean Legacy Project, which has worked for over six years to help make these protected waters a reality. With the new parks, more than 40 percent of Chilean waters have some level of legal protection.

The largest of the three regions is the Rapa Nui Marine Protected Area (MPA), where industrial fishing and mining will be prohibited but traditional fishing remains permissible. At 278,000 square miles, this area encompasses the entirety of the economic zone of Easter Island, safeguarding more than 140 native species and 27 that are threatened or endangered. Notably, it is one of the few marine protected areas in the world in which indigenous people had a hand—and a vote—in establishing the boundaries and level of protection. 

“I like to think of Easter Island as an oasis in the middle of an oceanic desert,” says Owen. The islands themselves are the peaks of an underwater ridge teeming with life. They also provide important spawning grounds for economically significant species like tuna, marlin and swordfish.

The second largest region is 101,000 square miles around Juan Fernández Islands, located some 400 miles offshore Santiago, Chile’s capital. Like Easter Island, these islands are also the peaks of lofty submarine mountains that rise from the deep ocean. But their slopes foster an unusual mix of tropical, subtropical and temperate marine life. All fishing and extraction of resources will be prohibited in this region, which boasts the highest known percentage of native species found in any marine environment. This area joins a small number of waters with complete protection: Only about 2 percent of the oceans are fully protected to date.

Finally, around 55,600 square miles of fully protected waters encompass the kelp forests of Diego Ramirez island, Chile’s southernmost point. Like the trees of a rainforest, the towering lines of kelp support a bustling underwater city and nursery for young sea creatures. These massive photosynthesizers are also believed to lock away a significant fraction of the world’s carbon dioxide.

The Diego Ramirez waters are some of the last intact ecosystems just outside the Antarctic region. “It’s really wild and pristine,” says Alex Muñoz, director for Latin America of Pristine Seas, an initiative from the National Geographic Society that provided scientific support for the creation of the Juan Fernández and Diego Ramirez protected regions.

Finding a Balance

Oceans are the lifeblood of Chileans. With a narrow mainland featuring 4,000 miles of shoreline, the country is one of the world’s major fish exporters, providing $5.7 billion worth of seafood to countries around the world in 2016 alone. But the fisheries have suffered in recent years from overfishing and illegal operations in Chilean waters.

At their peak in 1994, local and industrial fishermen were extracting millions of tons of seafood. But by the early 2010′s disaster was on the horizon, according to a 2013 investigation by Public Radio International. The Jack Mackerel, a particularly popular fish, provides a potent example of this decline. In the mid 1990s, fishermen netted 4.5 million tons of the fish, but by 2012 they caught fewer than 300,000 tons—due in large part to overfishing.

But conservation groups and the Chilean government have been working to reverse the trend. The new protected waters could shelter marine critters and help restore nearby areas through the “spillover” of ocean life outside the park, explains Mary Hagedorn, a research scientist with Smithsonian’s Conservation Biology Institute who was not involved in the park creation. ″The more we can protect these really productive areas, the more we allow spillover and recovery of [other damaged] areas,” says Hagedorn.

“Chile has demonstrated that being a fishing country doesn’t mean that you cannot also be a leader in marine conservation,” adds Muñoz. “It is true that Chile degraded its marine resources in the past, but now it has completely changed its vision and … found the value [of] protecting its oceans.″

Indigenous Voices

The Rapa Nui, who are the native Polynesians of Easter Island, were instrumental to the the creation of these protected zones. Ludovic Burns Tuki, executive director of Mesa del Mar, the organization spearheading the work towards ocean protections, stresses the Rapa Nui’s deep connection to the ocean. Renowned navigators who took to the seas hundreds of years before Europeans, their relationship to the ocean is one of “divine relation,” says Tuki, who has a Rapa Nui and Tahitian background. He explains that the ocean is a connection to the gods, and helps the Rapa Nui navigate the world, supplying food and providing waves for them to surf and dive.

Initially the Rapa Nui strongly opposed the idea of a marine park, fearing that such protections would take these important waters out of local hands. This fear has a historical basis: In 1933, for example, without consulting the Rapa Nui, the Chilean government declared the entirety of Easter Island public lands under the jurisdiction of the national government, meaning land could be leased for sheep farming and resource exploitation without local consent.

So when it came to a marine park, there was little trust that the protections would benefit the Rapa Nui. “There is so much that the state has [done] to my people,” says Tuki, “I understand [the concerns].” He voices the people’s worries over the marine park: “Restriction means I’m going to be a prisoner in my own ocean and my own land.”

Tuki, a avid spear fisherman, was originally of this same thinking. But as he saw fish populations declining, he grew more concerned for the future of his two children. As Tuki explains, “I say to my people: What we are going to decide ... right now, it’s going to be future of the next 50 years of Easter Island.”

It took years of extensive public outreach through weekly local meetings, radio appearances, and work with local schools, to foster a movement among Rapa Nui to protect the waters. But in September of 2017, the Rapa Nui voted with overwhelming support of the marine park.

The protections will prevent industrial fishing and mineral extraction, but still allow the traditional fishing methods of Easter Island’s people. The catch of traditional fisheries is often “not insignificant,” says Hagedorn, but local fishing is often less detrimental than industrial extraction.

Traditional hook and line methods target specific creatures, rather than netting massive swaths of marine life and killing off unwanted catch as is common with industrial vessels. And the goodwill fostered on both sides of the table is worth the compromise, she says. “If you want to improve MPAs, and you want them to be more effective … you have to have that flexibility, you have to have that discourse and respect,” she says.

That was certainly the case for the Rapa Nui, whose support hinged on gaining exclusive fishing rights in the park. And most importantly, the people will also be involved in the management of the newly protected area. In a rare move, elected Rapa Nui officials will have the majority vote on the council tasked with regulating the waters.

Like his ancestors before him, Tuki believes these past and future efforts are merely an act of reciprocity. “This work that I do for the for the ocean of Rapa Nui is to give back what the ocean has given me all these years,” he says. “From the surfing to the diving and the navigation—all these great moments, and all this food that the ocean gives to me, I have to give back. That’s the balance.”

Wins and Losses

As with all marine protected areas, the resulting boundaries represent a compromise between opposing interests. Though conservation groups recommended a much larger area of protections in southern Chile, pressure from the Chilean sea bass industry led to a reduction of the planned park bounds and elimination of proposed protections further north around Cape Horn,  Muñoz explains. “That fishery is completely collapsed,” he says. “But the pressure was so strong the government decided not to protect the Cape Horn area...We’re all sorry about that.”

Still, the protections are an important step in working toward larger-scale conservation of marine resources. The International Union for Conservation of Nature (IUCN) suggests that at least 30 percent of the world’s oceans must be protected to help effectively conserve marine life and cope with the changing climate and pressures from the fishing industry.

Chile has made great strides toward this goal. The new protected regions join the Nazca-Desventuradas Marine Park, which encompasses 115,000 square miles of ocean. “It’s going to be very interesting to see how Chile and other nations can inspire protection,” says Owen. “We can kind of ride this wave, forgive the pun, towards that 30 percent.”

Yet there remains much to consider with the newly protected parks, explains Miriam Fernández, professor at the Pontificia Universidad Católica de Chile and Director of the Center for Marine Conservation. The push to establish a growing number of protected waters has often ignored the pressing issue of enforcing regulations. “For the Chilean government, there were significant advances in meeting international compromises (fraction of the ocean protected), but not significant advances in creating the institution that will assure actual protection, and the substantial funding that it will require,” she writes in an email to Smithsonian.com.

And NGOs, though they work to establish the MPAs, often disappear once the protections are signed into law, says Fernández—just when the region needs them most. Fortunately, Pristine Seas does plan to stick around, helping the government to optimize the use of limited funds and target areas most vulnerable to illegal fishing using advanced satellite imagery techniques.

Tuki is optimistic but realistic about the new protections. “Now, there is a lot of work to do,” he says. “This is only the first step.”

CONTINUE READING: https://www.smithsonianmag.com/science-nature/chile-protects-massive-swa...

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