Arquivo da tag: Ecologia marinha

Ocean’s Largest Dead Zones Mapped by MIT Scientists (Eco Watch)

MIT scientists have generated an atlas of the world’s ocean dead zones.
Oxygen-deficient zones intensity across the eastern Pacific Ocean, where copper colors represent the locations of consistently lowest oxygen concentrations and deep teal indicates regions without sufficiently low dissolved oxygen. Jarek Kwiecinski and Andrew Babbin

By Olivia Rosane – Jan 26, 2022 12:11PM EST

When you think of the tropical Pacific, you might picture a rainbow of fish ribboning their way between pinnacles of coral, or large sea turtles swimming beneath diamonds of sunlight. But there are two mysterious zones in the Pacific Ocean where life like this cannot survive. 

That is because they are the two largest oxygen-deficient zones (ODZ) in the world, which means they are a no-go zone for most aerobic (oxygen-dependent) organisms. Two Massachusetts Institute of Technology (MIT) scientists recently succeeded in making the most detailed atlas to date of these important oceanic regions, revealing crucial new facts about them in the process. The new high-resolution atlas was described last month in the journal Global Biogeochemical Cycles

“We learned just how big these two zones in the Pacific are, reducing the uncertainty in the measurement, their horizontal extent, how much and where these zones are ventilated by oxygenated waters, and so much more,” Andrew Babbin told EcoWatch in an email. Babbin is one of the atlas’s two developers and Cecil and Ida Green Career Development Professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “Being able to visualize in high resolution the low oxygen zones really is a necessary first step to fully understanding the processes and phenomena that lead to their emergence,” he said.

Natural Dead Zones

Oxygen-deficient zones can also be referred to as hypoxic zones or dead zones, as the National Oceanic and Atmospheric Administration explains. They can be caused by human activity, especially nutrient pollution. For example, the world’s second-largest dead zone is in the Gulf of Mexico, and is largely caused by the runoff of nitrogen and phosphorus from cities and factory farms.

The new atlas focuses on two naturally-occurring ODZs in the tropical Pacific, however. One is located off the coast of South America and measures about 600,000 cubic kilometers (approximately 143,948 cubic miles), or the equivalent of 240-billion Olympic swimming pools, MIT News reported. The second is around three times larger and located in the northern hemisphere, off the coast of Central America. 

Both natural and anthropogenic ODZs have something in common: too many nutrients. In the case of the Pacific ODZs, Babbin said, those nutrients build up because of wind patterns that push water offshore. 

“Deeper water then upwells to fill in this void, bringing higher nutrients to the surface,” Babbin told EcoWatch. “Those nutrients stimulate a massive amount of growth of phytoplankton, akin to how we fertilize crop lands and even our potted plants at home. When those phytoplankton then sink, heterotrophic bacteria act to decompose the organic material, consuming oxygen just like humans do to respire our food.” 

However, because of where these zones are located, it takes a long time for oxygen-rich waters to reach the area and replenish what the bacteria gobble up.

“In essence, the biological demand of oxygen outpaces the physical resupply,” Babbin concluded. 

While these specific zones aren’t caused by human pollution, understanding them is still important in the context of human activity. ODZs can emit the greenhouse gas nitrous oxide, and there is a concern that the climate crisis may cause them to expand.

“It’s broadly expected that the oceans will lose oxygen as the climate gets warmer. But the situation is more complicated in the tropics where there are large oxygen-deficient zones,” atlas co-developer Jarek Kwiecinski told MIT News. “It’s important to create a detailed map of these zones so we have a point of comparison for future change.”

A ‘Leap Forward’ 

The new atlas improves on previous attempts to measure the Pacific ODZs because of the amount of information it incorporates and the approach it took to measuring the oxygen content of the water. Instead of relying on direct measurements of the water’s oxygen content, the atlas designers looked for places in the water where the oxygen content did not change no matter the depth. They interpreted the lack of change as an absence of oxygen.

“This new approach, compiling tens of thousands of profiles and over 15 million individual measurements, is a leap forward in the representation of these climate critical regions,” Babbin and Kwiecinski wrote in Global Biogeochemical Cycles. 

The data Babbin and Kwiecinski used for the atlas was gathered by research cruisers and robotic floats over a period of more than 40 years, MIT News reported. Scientists have typically dropped bottles to various depths and measured the oxygen content of the water collected by the bottle. However, this measurement is not entirely accurate because the plastic from the bottle itself also contains oxygen. 

To avoid this problem, the team behind the atlas instead looked at data from sensors attached to the bottles or to robotic platforms, which allowed them to track oxygen content as the sensors descended through the water column. 

“This method then allows us to get around a bias that exists in the absolute data to only look at whether oxygen is increasing, decreasing, or staying the same,” Babbin said.

The result is a high-resolution atlas that maps the volume, shape and borders of the two ODZs, as well as places where the oxygen-deprived waters are thicker or thinner. They found that the lack of oxygen is more concentrated towards the middle, while more oxygen-rich waters enter towards the edges. 

Now that the atlas is complete, Babbin hopes to use it to plan more research in the area. Specifically, he intends to study the metabolism of the bacteria in the zones in order to better assess nitrous oxide pollution. But the atlas was not just designed to further one team’s research. 

“We hope the atlas will be used by everyone!” Babbin said. “We can anticipate oceanographers and climate scientists to use it to plan expeditions or relate some of their data to a broad atlas/compilation. We hope climate modelers might use it to validate their models that try to reproduce the extent of low oxygen in their models. We further think that this compilation will act as a comparison point against which future measurements can be compared to finally reveal how these zones respond in the face of a changing climate.”

If you are interested in checking it out, the atlas is available from the Biological and Chemical Oceanography Data Management Office (BCO-DMO), and the data can be downloaded from the Woods Hole Open Access Server.

Correction: A previous version of this article incorrectly stated that anaerobic organisms were oxygen-dependent. Aerobic organisms are oxygen-dependent. This page has been updated.

Linking Social Science, Ecology to Solve the World’s Environmental Problems (Science Daily)

Dec. 16, 2013 — Researchers from the ARC Centre of Excellence for Coral Reef Studies (CoECRS) at James Cook University are engaging social science to help solve some of the world’s biggest environmental problems.

Dr Christina Hicks, an interdisciplinary social science fellow at the ARC CoECRS, holds a joint position with the Center for Ocean Solutions at Stanford University in the USA.

Dr Hicks says more powerful economic interests, such as tourism, currently drive coral reef management. Little thought is given to community needs such as food or wellbeing. This results in conflict.

Dr Hicks explains to improve long-term coral reef management, “human values need to be considered in decision-making.”

Dr Nick Graham, a senior research fellow at the ARC CoECRS, adds that humans play an essential role in ecology, but different people have different priorities. He says these priorities need to be considered when managing natural environments.

For example, in a recent co-authored paper for the journal Global Environmental Change, Dr Hicks and Dr Graham, along with Dr Joshua Cinner, measured and compared how managers, scientists and fishers prioritized specific benefits from coral reef ecosystems. This in effect highlighted key areas of agreement and conflict between the three different stakeholder groups.

Dr Graham says the lack of ‘ownership’ of reef resources for fishers, who depend on fish for their food and livelihoods, underlies a main area of conflict. But the paper also indicated that managers might be well placed to play a brokering role in disagreements.

“Communities that are engaged and recognized are more likely to trust and support their management agencies,” adds Dr Hicks. She explains that governments who consult local communities in order to develop co-management plans generally reduce conflict and see increased livelihood as well as ecological benefits (such as a rise in fish stocks) in their area.

Examples of successful co-management arrangements exist in coral-reef nations such as Papua New Guinea and Kenya.

Journal Reference:

  1. Christina C. Hicks, Nicholas A.J. Graham, Joshua E. Cinner.Synergies and tradeoffs in how managers, scientists, and fishers value coral reef ecosystem servicesGlobal Environmental Change, 2013; 23 (6): 1444 DOI:10.1016/j.gloenvcha.2013.07.028

Has a marine mammal conservation program become too successful? (Slate)

Great White Sharks Are Back

By |Posted Tuesday, July 2, 2013, at 4:05 PM

Great white shark.

Today, a great white shark sighting is more likely to elicit curiosity than fear. Cape Cod sharks even have their own advocacy group. Photo by Steven Benjamin/iStockphoto/Thinkstock

When a tourist from Colorado was bitten by a great white shark last summer while swimming off Cape Cod, an excited media made predictable comparisons to the 1975 blockbuster Jaws. The 50-year-old man, who was fortunate to survive with bites to his legs but with all his limbs still attached, was the first human to be attacked by a shark in Massachusetts waters since 1936. As more sighting reports poured in, 2012 became Cape Cod’s “Summer of the Shark.”

We all love a good shark scare, but in this case the coverage wasn’t completely exaggerated. In 1974, when Jaws was filmed just off the cape on Martha’s Vineyard, great white sharks—known to marine biologists simply as white sharks—were rare, with one or two spotted in New England waters each year. In 2012, there were more than 20 confirmed sightings at Cape Cod beaches, and so far this summer two beaches have been closed temporarily after the sharks’ telltale dorsal fins were seen just offshore. Scientists have now tagged 34 great whites off of Cape Cod, and the data show the minivan-size fish sticking to a clear migration pattern—down south or out to sea in the winter and, like the Kennedys, back to the cape every summer.

Jaws aside, these sharks are not hunting unsuspecting vacationers. They’re after seals, which have soared in population in recent years thanks to a national conservation effort that has proven enormously successful—some might say too successful. The shark resurgence comes down to simple food chain economics, but it also shows how wildlife conservation can sometimes have weird and unpredictable consequences.

Seals have a tendency to hang around boats and snatch fish from nets, and for centuries people fishing off New England would kill any seal they saw. Between the late 19thcentury and the early 1960s, the state of Massachusetts offered a bounty of up to $5 for every pinniped slaughtered. By 1972, harbor seals, once common on Cape Cod, were becoming rarer, and gray seals were all but wiped out. But that year Congress passed the Marine Mammal Protection Act, a law that forbids the killing, capture, or harassment of whales, dolphins, polar bears, manatees, seals, and similar animals—creatures that commercial hunting and other human activity had taken, in some cases, to the brink of extinction.

The act has been a tremendous success. In March 2011, a one-day count of gray seals in Massachusetts waters found 15,756 of them, compared to 5,611 in 1999. The National Oceanic and Atmospheric Administration estimates that the gray seal population in the Western Atlantic grew annually between 6 and 9 percent during the past three decades. Today, seals haul out and lounge on some beaches in enormous numbers, and it’s common to see them swimming alone or in pairs up and down the Atlantic side of Cape Cod. That’s a lot of shark bait. One recent afternoon at Nauset Light Beach, part of the Cape Cod National Seashore, I stood on the sand with a group of beachgoers watching a sleek brown head bobbing just past the breakers. Having been warned by prominent signs not to swim near seals, none of us were going near the water. “Does this mean there are sharks out there?” one woman asked, in a tone that revealed both anxiety and fascination.

Tourism is Cape Cod’s main industry, with domestic visitors spending some $850 million in 2011, and locals worry that if anyone were to be killed or badly hurt by a shark, tourists might start to avoid cape beaches. In an effort to educate people about shark safety, beach authorities have erected notice boards, and towns are using a $50,000 state grant to print brochures with helpful shark safety tips—chief among them, “Avoid swimming near seals.” Looking to South Africa, which has been dealing with great white sharks for years, Cape Cod officials have talked about setting up a system for shark detection, perhaps by using spotter planes or installing more acoustic buoys to track tagged sharks. But so far there isn’t enough funding for a major effort.

Seals are taking the blame for luring sharks, and at the same time the old resentment is flaring up among some fishermen, who say seals are harming the cape’s struggling fishing industry. Gordon Waring, a seal specialist at the NOAA, cautions that marine biologists don’t actually know how seals interact with fisheries, and so far there is no sign that they are eating more than their habitat can support. But it is clear that seals are attracted to fishing boats and piers, and fishermen who watch seals stealing fish from their nets justifiably resent the greedy creatures, which the Marine Mammal Protection Act says can’t even be shooed away (that would be “harassment”). Fish stocks, particularly of cod, are down, and while that’s mostly due to other factors such as decades of overfishing, seals are a visible target for blame. There has even been talk of a seal cull, and a Nantucket-based group calling itself the Seal Abatement Coalition is lobbying Congress to remove gray seals from the list of species covered by the Marine Mammal Protection Act. Seal culls are already a regular occurrence in Canada, which has historically had much larger seal populations.

That might all sound like we’re headed for a return to the era when seals were shot on sight and sharks stalked and killed to protect swimmers, but in truth there are heartening signs that humans’ relationship with ocean life off Cape Cod will be better this time around. While a horror movie starring an animatronic shark could once keep people out of the water all summer, today, a great white sighting is more likely to elicit curiosity than fear. Cape Cod sharks even have their own advocacy group.

Gray seal hanging around at the Chatham Fishing Pier.Seals have a tendency to hang around boats and snatch fish from nets. Courtesy of Amy Crawford

“As tragic as a shark attack is, it would be more tragic not to have sharks in our oceans,” says Cynthia Wigren, who last summer helped found the Atlantic White Shark Conservancy, a Cape Cod group (with an adorable smiling shark logo) that raises money for education and research. Greg Skomal, a shark biologist with the Massachusetts Division of Marine Fisheries, has been leading an effort to tag great whites and study their migration patterns. He sees the sharks’ return as an indication that the marine ecosystem off New England is returning to normal, with sharks playing a crucial role as apex predators. That’s great news, ecologically speaking. But as he points out, “That does not take into consideration the negative impacts that can occur with the restoration of a natural ecosystem.”

Sharks are not the brightest animals in the sea. Humans are not a preferred prey animal, but sharks looking for seals sometimes get confused. Given that their primary way of interacting with the world is to use their mouths (in a way, maybe they are the “mindless eating machines” of the Jaws trailer), a shark may give a human swimmer a good “gumming,” Skomal says, before realizing it hasn’t found a seal. “If sharks wanted to eat humans, we’d have a hell of a lot more shark attacks,” Skomal says. “These are instinctive wild animals, and they make mistakes every now and then. It’s extremely rare, but nonetheless they make mistakes.”

While a great white shark’s honest mistake can still be terrifying—just ask that tourist who got bitten last summer—sharks’ public image seems to be evolving as conservationists educate people about the need to protect vulnerable species and as our understanding of nature becomes more sophisticated. We may be learning to adapt to nature, rather than forcing it to adapt to us.

Nowhere is that more apparent than in Chatham, a 300-year-old fishing village on the elbow of Cape Cod that has found itself at the epicenter of the wildlife resurgence. InJaws, small town leaders tried to cover up shark attacks, fearing they would be bad for business. But Lisa Franz, director of Chatham’s Chamber of Commerce, says the opposite has been true—at least so long as no one has been seriously hurt. While the local fishing industry is struggling, other businesses are capitalizing on people’s curiosity about sharks and the seals they feast on. Shark T-shirts and stuffed toys are flying off gift shop shelves, and there’s talk of making Chatham an ecotourism destination.

“When the first shark hits the newspapers, we get busier earlier,” says Keith Lincoln, who runs a Chatham cruise business that specializes in seal tours. His “office,” parked recently in a lot at the Monomoy National Wildlife Refuge, is a Honda Odyssey with an inflatable shark strapped to the roof—“a hit with the tourists,” he says. But while passengers might say they want to see sharks, Lincoln is not sure they know what they’re getting into. He has seen great whites swimming near the beach, their huge forms casting dark shadows on the sand below. “We usually don’t tell people,” he says. “They leave here all brave, but when they see a fish that’s as big as the boat, they’re not so brave.”

Then again, he might just need a bigger boat.

Watch Discovery Channel’s joking take on the shark frenzy for seals here.

The Worst Marine Invasion Ever (Slate)

I could not believe what I found inside a lionfish.

By Christie Wilcox |Posted Monday, July 1, 2013, at 7:00 AM

A Lionfish swims in a display tank in the aquarium on the United Arab Emirate of Sharjah on August 6, 2008.

A lionfish in an aquarium. Photo by Alexander Klein/AFP/Getty Images

“Do you know what this is?” James Morris looks at me, eyes twinkling, as he points to the guts of a dissected lionfish in his lab at the National Ocean Service’s Center for Coastal Fisheries and Habitat Research in Beaufort, N.C. I see some white chunky stuff. As a Ph.D. candidate at the Hawaii Institute of Marine Biology, I should know basic fish biology literally inside and out. When I cut open a fish, I can tell you which gross-smelling gooey thing is the liver, which is the stomach, etc.

He’s testing me, I think to myself. Morris is National Oceanic and Atmospheric Administration’s pre-eminent scientist studying the invasion of lionfish into U.S. coastal waters. He’s the lionfish guy, and we met in person for the first time just a few days earlier. We’re processing lionfish speared by local divers, taking basic measurements, and removing their stomachs for ongoing diet analyses. Not wanting to look bad, I rack my brain for an answer to his question. It’s not gonads. Not spleen. I’m frustrated with myself, but I simply can’t place the junk; I’ve never seen it before. Finally, I give up and admit that I’m completely clueless.

Close-up on the insides of an obese North Carolinian lionfish.

Close-up on the insides of an obese North Carolinian lionfish. Photo by Christie Wilcox

“It’s interstitial fat.”


“Fat,” he says firmly. I look again. The white waxy substance hangs in globs from the stomach and intestines. It clings to most of the internal organs. Heck, there’s got to be at least as much fat as anything else in this lionfish’s gut. That’s when I realize why he’s pointing this out.

“Wait … these lionfish are overweight?” I ask, incredulous.

“No, not overweight,” he says. “Obese.” The fish we’re examining is so obese, he notes, that there are even signs of liver damage.

Obese. As if the lionfish problem in North Carolina wasn’t bad enough.

Though comparing invasions is a lot like debating if hurricanes are more devastating than earthquakes, it’s pretty safe to say that lionfish in the Atlantic is the worst marine invasion to date—not just in the United States, but globally. Lionfish also win the gold medal for speed, spreading faster than any other invasive species. While there were scattered sightings from the mid-1980s, the first confirmation that lionfish were becoming established in the Atlantic Ocean occurred off of North Carolina in 2000. Since then, they have spread like locusts, eating their way throughout the Caribbean and along every coastline from North Carolina to Venezuela, including deep into the Gulf of Mexico. When lionfish arrive on a reef, they reduce native fish populations by nearly 70 percent. And it’s no wonder—the invasive populations are eight or more times as dense than those in their native range, with more than 450 lionfish per hectare reported in some places. That is a lot of lionfish.

These alien fish didn’t just come here on their own. Early guesses as to how the lionfish arrived ranged from ships’ ballast water to the coastal damage caused by Hurricane Andrew, but now scientists are fairly sure that no ships or natural disasters are to blame. Instead, it’s our fault. Pretty, frilly fins made the fish a favored pet and lured aquarists and aquarium dealers into a false sense of security. We simply didn’t see how dangerous these charismatic fish were—dangerous not for their venom, but for their beauty. We have trouble killing beautiful things, so instead we choose to release them into the wild, believing somehow that this is a better option when, in actuality, it’s the worst thing we can do. Released animals rarely survive in the harsh real world, but it’s even worse when they do. Pet releases and escapees have become problematic invaders all over the country, from the ravenous pythons in Florida to the feral cats of Hawaii. In the case of lionfish, multiple releases from different owners likely led to enough individuals to start an Atlantic breeding population. Rough genetic estimates suggest that fewer than a dozen female fish began what may go down in history as the worst marine invasion of all time.

Lots, and lots, of lionfish caught by the Discovery Diving crew on one day.

Lots and lots of lionfish caught by the Discovery Diving crew on one day. Courtesy of Discovery Diving

In North Carolina, the lionfish invasion can be seen at its worst. Offshore, where warm waters from the Gulf Stream sweep up the coast, the lionfish reign. Local densities increased 700 percent between 2004 and 2008. I got to witness the unfathomable number of lionfish firsthand when I dove with the crew of Discovery Diving, a local scuba shop, to compete in North Carolina’s inaugural lionfish derby. I’ve never seen so many lionfish in my life. I didn’t get more than 20 yards from my starting point before I saw hundreds—literally, hundreds. My spear couldn’t fly fast enough to catch them all. On the last day of the tournament, a six-diver team bagged 167 lionfish from one site in two dives, and they didn’t even make a dent in the population on that wreck site. Morris estimates that more than 1,000 lionfish are at this site. Let me tell you, this is what an invasion looks like. An ecological cascade has been set in motion by these Indo-Pacific fish, and scientists are frantically gathering data, learning as much as they can to understand the extent of the damage lionfish will inflict, and figuring out the best responses to protect these fragile marine ecosystems.

Despite the destruction, it’s hard not to be impressed by these colorful aliens. Part of me holds lionfish in the highest regard, with a sort of evolutionary awe. They’re an incredible fish. Given complete creative freedom, I cannot imagine a way to design a marine species more suited to dominance. Sure, they might not be at the top of the food chain like sharks or killer whales, but what they lack in size they make up for in adaptability and reproductive output. The key to their Darwinian success is that they grow fast, mature early, and breed year-round. A single female can release upward of 2 million eggs annually that become larvae capable of floating along currents for more than a month, dispersing for hundreds to thousands of miles. They’ll eat whatever they can get their mouths around, which happens to be any fish or invertebrate just a hair smaller than they are, and they can grow to more than 18 inches long. That means young fish and crustaceans of any species that live where lionfish do are potential targets. And, to top it all off, they are armed with a formidable set of long, sharp venomous spines capable of inducing incapacitating pain. Not surprisingly, nothing seems inclined to eat them. They’re known for their cavalier attitude toward divers, ignoring our presence or possessing the gall to approach us head on, even in the face of a spear. Their cocky resolve is admirable. It’s abundantly clear that these fish fear nothing, not a hungry grouper, not the largest of reef sharks, not even the most effective predators on the planet—us.

Christie Wilcox cutting open a lionfish to remove its stomach.

The author cuts open a lionfish to remove its stomach. Photo by NOAA intern Dave Matthews

Of course, we are perhaps the only animal that lionfish should be fearful of, the only species potentially capable of controlling lionfish populations. Scientists, managers, fishermen, and locals from Venezuela to North Carolina are rallying behind “Eat Lionfish” campaigns. Lionfish tournaments have become annual events in some of the most heavily hit areas of the Caribbean and Atlantic. The Reef Environmental Education Foundation released a lionfish cookbook in 2010 to spur culinary interest and inform fishermen and chefs how to clean and prepare this new delicacy. But even with a serious fishery throughout the invasive range, we will likely never evict lionfish from their new homes. Studies have suggested that we’d need to fish more than a quarter of the mature lionfish every month to stunt population growth, let alone reverse it. Our best hope is to keep local populations low enough to protect key commercial and ecological species, a mission that is proving to be harder and harder as we realize just how much lionfish eat.

We’ve always known that lionfish are formidable predators. As slow-moving fish, they have to be pretty effective hunters to get away with such flamboyant looks. After all, it’s not like their prey won’t see them coming. They practically advertise their presence, waving around their frilly, striped fins with a level of arrogance usually reserved for apex predators. In their native range, young fish run from the sight. But in the Atlantic, native fish have never seen such a bizarre-looking predator. They don’t realize that this colorful display is a warning, not only of their potent venom but also of a nearly insatiable appetite. They don’t flee, and they get eaten. And in North Carolina, the lionfish are eating so well they’ve become fat. No, not fat. Obese.

As James Morris and I measured and sliced 247 fish last month, he explained that we have to monitor their diets to understand how lionfish may impact native fish.

So far, more than 70 different species have been found in the stomachs of invasive lionfish, but detailed data on what they regularly eat in many different areas and throughout the year hasn’t been collected—yet. That’s one of the questions Morris is in the process of answering, and that’s what I helped him with while I was in North Carolina collecting samples for my own research on lionfish venom.

The coast of North Carolina is renowned for its seafood. Cold waters from the north and the warm Gulf Stream converge at Cape Hatteras, creating some of the richest fishing grounds on the Eastern Seaboard. More than 60 million pounds of fish and shellfish are pulled out of its waters every year, worth upward of $1 billion to commercial fishermen. Lionfish are eating a lot of something, and if these gluttons are eating key commercial species, there could be a negative ripple effect on the local economy.

Vermilion snapper pulled from a lionfish's stomach.

Vermilion snapper pulled from a lionfish’s stomach. Courtesy of NOAA

One species Morris is particularly concerned about is the vermillion snapper. One of the smallest of the species often labeled as red snapper, vermilion snapper are the most frequently caught snapper along the southeastern United States. Because of their popularity, vermilion snapper populations are closely monitored, and their harvest has been managed in a variety of ways, including limited entry systems, annual quotas, size limits, trip limits, and seasonal closures. So far, government assessments say that the populations are not overfished, but fisheries-watch organizations such as the Monterey Bay Aquarium aren’t convinced. What we know for certain is that vermillion snapper are among the most heavily managed fish in North Carolina, and all of our efforts will be for naught if the lionfish are getting to them first.

So far, it’s not looking good.

I personally pulled vermillion snapper out of lionfish guts last month, along with tomtates and various other reef fish. It’s estimated that lionfish in the Bahamas eat upward of 1,000 pounds of prey per acre per year. Given that lionfish feed largely on small fishes, this equates to hundreds of thousands of individual fish consumed per year by lionfish per acre. But all the interstitial fat I saw suggests that the North Carolinian fish aren’t just eating until they’re full; they’re overindulging on the rich diversity of seafood that North Carolina has to offer. Though lionfish can go weeks between meals, when they don’t have to, they won’t. Scientists have observed lionfish eating at a rate of one to two fish per minute, and their stomachs can expand 30 times their size to accommodate lots of food. To become obese, fish eat upward of 7.5 times their normal dietary intake, which means the abundant North Carolina lionfish could be eating as much as 7,000 pounds of prime North Carolina seafood per acre every year—seafood that we’d much prefer ended up on our plates instead.

In 2010 scientists named the lionfish invasion one of the top 15 threats to global biodiversity. In the three years since, the invasion has only worsened. The only solution is to fight fire with fire, or in this case, pit our bottomless stomachs against theirs. We really do have to eat them to beat them.

Unfortunately, developing a fishery for lionfish isn’t as straightforward as it sounds. They don’t tend to bite hooks and live in complex habitats like reefs and wrecks that can’t be fished with large nets. To catch them, people have to get in the water and spear them one by one—an expensive and tedious way to fish. For lionfish fisheries to turn a profit, demand will have to be high and constant. So far, only a handful of local restaurants have taken the bait, enticing locavores with a truly sustainable menu option. Their business alone isn’t enough, though, to really drive a market.

That’s even assuming that lionfish are completely safe to eat. Recently, the Food and Drug Administration raised flags about lionfish—but not because of their venom. They are concerned that lionfish may contain ciguatoxin, a common tropical poison that causes somewhere between 50,000 and 500,000 cases of ciguatera fish poisoning every year. Ciguatera isn’t unique to lionfish; the disease occurs in tropical waters worldwide. The small lipid ciguatoxins that cause it are made by dinoflagellates, microscopic algaelike animals that live on and near reefs. Animals don’t really break down ciguatoxin, so it bioaccumulates up the food chain, thus large predators that eat high on the food web are most likely to have dangerous levels of ciguatoxin. In areas where the disease is endemic, species such as groupers and barracuda are simply too risky to consume and are often avoided by fishermen. The FDA is concerned that lionfish should also be included on that list, meaning that in areas such as the Virgin Islands, lionfish would be permanently off the menu. Their press release stated that more than a quarter of lionfish sampled contained unsafe ciguatoxin levels, and it issued a warning against eating them.

To other scientists, including myself, the news is baffling. I haven’t seen the actual data (because the FDA has yet to release them), but such high numbers just seem unbelievable. Thousands of lionfish are eaten every year after tournaments, and there hasn’t been a single case of ciguatera from a lionfish. If so many are dangerous, why hasn’t anyone gotten sick? And even if some areas do have ciguatoxic lionfish, surely other areas are safe. After all, we can still eat grouper and other predators from much of the Atlantic and Caribbean. Lionfish shouldn’t be more ciguatoxic than other reef fish—not unless their diet is very, very different.

One of the tough things about ciguatoxin is that we don’t have reliable, direct tests for it. There is a diverse set of indirect assays, all with different methods, different detection levels, and different specificities. All of this makes it hard to compare studies done by different labs and hard to ensure accuracy. Top that off with a species that has never been tested for ciguatoxin before, and things get really messy. This is where my research comes in.

Lionfish possess potent venom that activates sodium channels on the surface of nerve cells, causing a massive influx of calcium. This leads to the release and depletion of the neurotransmitter acetylcholine. This happens to be the exact same thing ciguatoxin does. Which, to me, raises a very important question: What if lionfish venom is getting into ciguatoxin assays? Are venom compounds causing false positives? The venom itself, though excruciating in the form of a sting, is harmless on the plate. Unlike ciguatoxin, it’s readily degraded by heat, so if it is venom and not ciguatoxin causing positive tests, lionfish may be safer to eat than the FDA data suggest. Hopefully, the samples I collected on this trip to North Carolina—where ciguatoxin isn’t an issue—will provide some answers.

James Morris pulling a lionfish's stomach for gut content analyses.

James Morris pulling a lionfish’s stomach for gut content analyses. Courtesy of NOAA

Until we know more, though, promoting fisheries is a potentially dangerous management strategy, at least in certain areas. Some governments have stepped in to promote hunting even without a formal fishery plan, in an attempt to protect their reefs’ future. But many of the small, developing countries in the Caribbean simply don’t have the resources to fund large-scale lionfish removal efforts. For them, steady fisheries would be the only way to get fishermen to catch lionfish instead of currently lucrative species such as grouper.

While we wait to see whether we can drum up the demand, the lionfish are making themselves comfortable. They’re embedding themselves in already fragile ecosystems, restructuring food webs, and pushing reefs toward irreversible ecological cascades. They’re exploring new habitats, discovering the rich resources provided by seagrass meadows and mangroves, even travelling miles inland and upstream in Florida. They’re taking over reefs, wrecks, and rocky territory from the surface to more than 800 feet deep, and they’re gorging themselves on whatever young fish happen to live there. They are, quite literally, growing fat off of our inaction.

That’s not to say there is no hope. Yes, we’re going to have to learn to live with the lionfish. We’re going to have to accept their presence in the Atlantic, Caribbean, and Gulf of Mexico, but we can use science to arm us against this invasion. In the quiet lab in North Carolina, Morris isn’t just studying fish. He’s preparing us for battle. In this endless war with a formidable foe, knowledge truly is power. The power to predict. The power to pre-empt. The power to fight back and save the species we value most. The power to educate and rally reinforcements to drive back invaders. The more we know about the lionfish, the better our strategies will be to deal with them and future invaders and the better our chances of success. The lionfish caught us by surprise, but Morris isn’t going to let them stay one step ahead. Even if we can’t eradicate these gluttonous fish, we may be able to manage them and minimize the damage they do to our precious marine ecosystems.

Considering it’s our fault that lionfish are here in the first place, it’s really a war against ourselves: against our bad habits, against our casual disregard for the ecosystems that protect and sustain us, against the attitudes and mindsets that led to such a devastating invasion to begin with. It’s a war that, as a nation, as a species, we cannot afford to lose. And one thing is for certain: With so much at stake, it’s going to be a bloody one.

Zonas costeiras em debate (Ministério do Meio Ambiente)

Leila Swerts aponta problemas das áreas litorâneasMartim Garcia/MMA. Leila Swerts aponta problemas das áreas litorâneas

Ações do Programa Nacional de Gerenciamento Costeiro são apresentadas em seminário realizado nesta quinta-feira na Câmara dos Deputados


A proteção dos ecossistemas marinhos e das áreas costeiras do país está em pauta no Congresso Nacional. A Câmara dos Deputados realiza, nesta quinta-feira (11), o seminário “25 Anos da Constituição Federal e a Proteção dos Ecossistemas Costeiros e Marinhos”. O encontrou tem o objetivo de promover o diálogo entre os diversos órgãos governamentais e a sociedade civil sobre os impactos e alterações que a zona litorânea do país tem sofrido, além de propor alternativas e soluções para o problema.

Muitas das ações relativas ao tema são definidas no âmbito do Grupo de Integração do Programa Nacional de Gerenciamento Costeiro (GI-Gerco), formado por representantes do governo federal, da academia, do Ministério Público Federal (MPF) e do terceiro setor. Segundo a coordenadora da Gerência Costeira da Secretaria de Extrativismo e Desenvolvimento Rural Sustentável do MMA, Leila Swerts, a participação de segmentos diferenciados garante a efetividade do processo.

Os riscos à zona costeira foram mencionados pela coordenadora durante o debate realizado na manhã desta quinta-feira. De acordo com a coordenadora, 24% da população do país vivem nessas regiões e os problemas vão desde o crescimento desordenado aos efeitos causados pelas mudanças climáticas. “Está havendo um adensamento dessas áreas e, por isso, estamos trabalhando pelo aumento de pautas relacionadas à gestão costeiras dentro do colegiado”, explicou Leila, que integra o comitê executivo do GI-Gerco.


Entre os projetos do MMA para a preservação da zona costeira está o Sistema de Modelagem Costeira (SMC), desenvolvido em parceria com a Espanha. Criado originalmente pelo país europeu, a iniciativa consiste em uma base de dados que permite o monitoramento das linhas de praias. O objetivo é fazer uma plataforma nos mesmos moldes em território nacional para qualificar o planejamento e a tomada de decisões destinadas ao litoral brasileiro.

O diretor do Programa Marinho da Conservação Internacional (CI), Guilherme Dutra, destacou a importância do uso da tecnologia nesse processo. “É necessário medir e estudar o que está ocorrendo com os oceanos e precisamos ter acesso a essas informações, ou seja, de pactos pela governança, pelo planejamento e pela sustentabilidade”, defendeu Dutra, que representou a sociedade civil no Painel Governamental do evento.

Ocean’s Future Not So Bleak? Resilience Found in Shelled Plants Exposed to Ocean Acidification (Science Daily)

Apr. 12, 2013 — Marine scientists have long understood the detrimental effect of fossil fuel emissions on marine ecosystems. But a group led by a UC Santa Barbara professor has found a point of resilience in a microscopic shelled plant with a massive environmental impact, which suggests the future of ocean life may not be so bleak.

This shows cells of the coccolithophore species Emiliania huxleyi strain NZEH under present-day, left, and future high, right, carbon dioxide conditions. (Credit: UCSB)

As fossil fuel emissions increase, so does the amount of carbon dioxide oceans absorb and dissolve, lowering their pH levels. “As pH declines, there is this concern that marine species that have shells may start dissolving or may have more difficulty making calcium carbonate, the chalky substance that they use to build shells,” said Debora Iglesias-Rodriguez, a professor in UCSB’s Department of Ecology, Evolution and Marine Biology.

Iglesias-Rodriguez and postdoctoral researcher Bethan Jones, who is now at Rutgers University, led a large-scale study on the effects of ocean acidification on these tiny plants that can only be seen under the microscope. Their research, funded by the European Project on Ocean Acidification, is published in the journal PLoS ONE and breaks with traditional notions about the vitality of calcifiers, or creatures that make shells, in future ocean conditions.

“The story years ago was that ocean acidification was going to be bad, really bad for calcifiers,” said Iglesias-Rodriguez, whose team discovered that one species of the tiny single celled marine coccolithophore, Emiliania huxleyi, actually had bigger shells in high carbon dioxide seawater conditions. While the team acknowledges that calcification tends to decline with acidification, “we now know that there are variable responses in sea corals, in sea urchins, in all shelled organisms that we find in the sea.”

These E. huxleyi are a large army of ocean-regulating shell producers that create oxygen as they process carbon by photosynthesis and fortify the ocean food chain. As one of Earth’s main vaults for environmentally harmful carbon emissions, their survival affects organisms inside and outside the marine system. However, as increasing levels of atmospheric carbon dioxide causes seawater to slide down the pH scale toward acidic levels, this environment could become less hospitable.

The UCSB study incorporated an approach known as shotgun proteomics to uncover how E. huxleyi‘s biochemistry could change in future high carbon dioxide conditions, which were set at four times the current levels for the study. This approach casts a wider investigative net that looks at all changes and influences in the environment as opposed to looking at individual processes like photosynthesis.

Shotgun proteomics examines the type, abundance, and alterations in proteins to understand how a cell’s machinery is conditioned by ocean acidification. “There is no perfect approach,” said Iglesias-Rodriguez. “They all have their caveats, but we think that this is a way of extracting a lot of information from this system.”

To mirror natural ocean conditions, the team used over half a ton of seawater to grow the E. huxleyi and bubbled in carbon dioxide to recreate both present day and high future carbon levels. It took more than six months for the team to grow enough plants to accumulate and analyze sufficient proteins.

The team found that E. huxleyi cells exposed to higher carbon dioxide conditions were larger and contained more shell than those grown in current conditions. However, they also found that these larger cells grow slower than those under current carbon dioxide conditions. Aside from slower growth, the higher carbon dioxide levels did not seem to affect the cells even at the biochemical level, as measured by the shotgun proteomic approach.

“The E. huxleyi increased the amount of calcite they had because they kept calcifying but slowed down division rates,” said Iglesias-Rodriguez. “You get fewer cells but they look as healthy as those under current ocean conditions, so the shells are not simply dissolving away.”

The team stresses that while representatives of this species seem to have biochemical mechanisms to tolerate even very high levels of carbon dioxide, slower growth could become problematic. If other species grow faster, E. huxleyi could be outnumbered in some areas.

“The cells in this experiment seemed to tolerate future ocean conditions,” said Jones. “However, what will happen to this species in the future is still an open question. Perhaps the grow-slow outcome may end up being their downfall as other species could simply outgrow and replace them.”

Journal Reference:

  1. Bethan M. Jones, M. Debora Iglesias-Rodriguez, Paul J. Skipp, Richard J. Edwards, Mervyn J. Greaves, Jeremy R. Young, Henry Elderfield, C. David O’Connor. Responses of the Emiliania huxleyi Proteome to Ocean AcidificationPLoS ONE, 2013; 8 (4): e61868 DOI:10.1371/journal.pone.0061868