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DW
4 days ago
- Science
- DW
Why are oceans getting darker? – DW – 06/06/2025
In the past 20 years more than a fifth of our oceans have been growing darker. What is causing this and how worried should we be? To mark World Ocean Day on June 8, we've repackaged a deep dive that will take you beneath the Baltic Sea to explore how ocean darkening is changing the marine ecosystem, plus the steps we need to take to protect our oceans. Interviewees: Claas Wollna, fisherman from Stralsund Oliver Zielinski, director of the Leibnitz Institute for Baltic Sea Research in Warnemünde Florian Hoffmann, biologist with the World Wildlife Fund in Stralsund Dag Aksnes, marine ecologist at the University of Bergen Maren Striebel, biologist at the Institute for Chemistry and Biology of the Marine Environment in Wilhelmshaven Listen and subscribe to Living Planet wherever you get your podcasts: Got a question for us? Email livingplanet@ And, if you like the show, leave us a rating and review on whichever podcast platform you use – and tell a friend! Transcript: Claas Wollna: That's perch, flounder, pike, zander and whitefish. That's fine, I had worse catch. It's a good morning for fisherman Claas Wollna. He has just come back from the gillnets and now heaves four boxes of catch onto the jetty. Some of the fish are still wriggling. Wollna is the last permanent fisherman in the region of Stralsund, a harbor town on the German coast of the Baltic Sea. Most of his colleagues have given up. Fishing no longer earned them a sufficient income. And that's because their most important fish, the herring, is almost gone. It doesn't reproduce sufficiently. To save the herring from extinction, Wollna is only allowed to catch a meagre 1.3 tons a year. Claas Wollna: I am not against protection of herring at all. I understand that if the stock is poor, it needs to be saved. But that needs to be done in a way that people can survive. Claas Wollna's struggle runs way deeper than mere fishing regulations. And the missing herring is just a symptom of a much a bigger problem. Something's fundamentally wrong with the water ... no, with the sea itself, all along the coast. Not just in the Baltic Sea, but at many coasts around the world. Something has changed. Dag Aksnes: And then we saw that the water down there was very dark. Florian Hoffmann: We could see about an arm's lenght. It wasn't even a meter. You're listening to Living Planet, I'm Neil King. And this deep dive is a literal one. We're about to explore the phenomenon of coastal ocean darkening, also known as coastal browning or brownification. Although 'known' seems to be a bit of an overstatement. A fairly small community of researchers around the world has only just begun to understand where this darkening comes from and how it messes up pretty much everything from seaweed to fishery and even the oceans' ability to help us protect the climate. To get started, we head to another harbor town on the German Baltic Sea coast, Warnemünde, to meet Oliver Zielinski a renowned expert on Coastal Ocean Darkening. Oliver Zielinski: Ocean darkening and specifically coastal ocean darkening refers to how much light gets into the depths of the ocean to a plant or a fish sitting at the bottom of the ocean. It refers to the light within the ocean itself, not as seen from above. From a bird's eye view, an ocean surface can shine brightly and yet be very dark under water. Oliver Zielinski is the director of the Leibnitz Institute for Baltic Sea Research. He has studied the darkening in the Baltic Sea and North Sea for years. However, the problem is a global one. Researchers found the darkening happening in the waters around New Zealand, the US, Singapore, China, Japan and in the Medditerranean Sea. Oliver Zielinski: …that's where we measured darkening of coastal waters. This is where we have long series of measurements and where human interaction with the ocean has been strong. 'Human interaction with the ocean' - we'll save this little bit of what Zielinski just said for later when we talk about what – or who – causes the darkening. Before that, we're taking a little walk with Zielinski to the harbor quay. He wants to show us something. A tool. Oliver Zielinski: I now lower the disk into the water and watch it slowly drift down from the surface. The disk that Zielinski puts in the water, is a Secchi disk, named after its inventor, Pietro Angelo Secchi, a 19th century priest and scientist in Italy. It is white and 30 cm in diameter. A bit like a large pizza plate on a cord. Zielinski is holding the cord with both hands, letting the disk sink down centimeter by centimeter into the water just off the quay. Oliver Zielinski: It is getting harder to see the disk now as the murky water covers it. The important thing is that I now figure out the exact depth at which I can hardly see the disk. If I lift it up a little now, I can see the disk again. That's it. And that is the depth I'll write down. The disk is roughly 2.5 meters under the sea surface. And according to Zielinski, light, as a rule of thumb, reaches down into the water three times as deep. That's ... 7.5 meters then. That sounds pretty deep actually, but it used to be much more. Since 1900, the depth of visibility, or Secchi depth, on the coasts of the Baltic Sea and North Sea has decreased by 3 to 4 centimeters per year. The question is: why did this happen? Oliver Zielinski: The water itself obviously didn't change over the past 100 years. So it's the substances that got into the water, three of them: algae, dissolved matter and sediments. Okay, so here is what we've got so far. Coastal waters around the globe have been getting darker for decades. Meaning that the depth to which light can reach into the water has decreased. And that's because of algae, dissolved matter and sediments. Let's explore what that exactly means – and what harm it does. We're in a speedboat, heading out to a lagoon in the Baltic Sea, east of Stralsund. We're not here on our own of course. Florian Hoffmann: I am Florian Hoffmann, I am a biologist and have been working with the World Wildlife Fund in Stralsund for 10 years. Florian has kindly agreed to take us out for a diving trip. We arrive at the lagoon. But if you're thinking of crystal-clear, turquoise water now, you won't find that here. Quite the opposite. But that's why we're here after all. We drop anchor near a small island, where many plants are supposed to grow on the seabed, like seaweed or crested pondweed, green and lush. The water is not that deep, only 2.5 meters, as the echo sounder on board indicates. You don't need big diving gear for this depth. So, we're already dressed with a wetsuit, now it's time for the flippers and the belt with heavy weights. Florian Hoffmann: I'll start with two weights. I'll go down and then tell you how much you take with you. Because the wetsuit leads to a little buoyancy. Time to spit on the diving goggles, rub the spittle so that the goggles don't fog up, adjust the mouthpiece of the snorkel - and we're ready to go. Hoffmann jumps first. Florian Hoffmann: Visibility is terrible. Let's go take a look for ourselves. The seabed is just a few strong pulls away. Gliding above it, we can only see about an arm's length, beyond that it gets dark. Not dark in the sense of black of course, we are in shallow water after all, more like a fog, a dense and murky mixture of brown and green. What we can see directly in front of us are patches of sand and then again patches of seaweed and other plants. Their stalks seem to pop up out of nowhere and sweep across our arms and face. To be honest, it's a bit of a confusing and uncomfortable environment at first, but after gaining some orientation, much of the murkiness seems to come from masses of small green particles. They float around in the water weightlessly, like artificial snow in one of those kitschy snow globes. Back on the boat, Florian Hoffmann explains what we just saw. The green particles, he says, that's phytoplankton, the basis of all life in the seas and producer of half the oxygen we breathe. So having phytoplankton in the seas is essential. But when there's too much of it, it makes the water foggy as it dies and slowly sinks to the ground. Florian Hoffmann:This means that the light zone decreases. ... We know from older literature that the depths to which you could look down into the water here used to be up to 8 meters. It now has decreased to three or two meters. And that of course makes it a lot harder for sea plants to grow on the seabed here. Hoffmann pulled out a handful of seaweed and brought it back on board. Some of the stalks are covered with small brown stains. The remains of phytoplankton shield the living plants from light even in death. The reason for this mess in the water lies on land, Hoffmann says. When farmers spread too much fertilizer on their fields, it doesn't only make their crops grow. Florian Hoffmann:That overuse of fertilizer leads to increased supply of water bodies with nutrients. That's nitrogen, which is important for photosynthesis, and phosphorus, a component of the DNA, which is also an important building block for life. Florian Hoffmann has brought a clipboard with him, with sheets of paper, showing charts and numbers. Florian Hoffmann:So, these are figures from the Federal Ministry of Environment from 2021. Agriculture accounted for 78% of nitrogen inputs in the Baltic Sea and 51% of phosphorus inputs, while point sources such as sewage treatment plants accounted for another 10% of nitrogen inputs and 20% of phosphorus inputs. Apart from these nutrients and water of course, it's light that makes photosynthesis possible and lets plants grow. Imagine if someone switched off the sun. How long would life on earth survive? The trees, the bushes, insects, birds, mammals, all life. This is a dark thought experiment. But looking at the foggy water underneath our boat out there on the lagoon, the threat seems real enough. If the seaweed doesn't get enough light, it dies. Like here in the lagoon. Spanning more than 500 km² big there used to be giant underwater seaweed lawn here just 70 years ago. Today, the plants have retreated to the shallow edges of the lagoon. This has effects on the whole food chain in the water and beyond. Small fish that are at the start of the chain use seaweed to hide and to spawn. In this part of the Baltic Sea, it's the herring that essentially depends on it as it lays its spawn in the seaweed. The herring population has massively collapsed over the last 10 years. In an unfavorable combination, the fish migrated to the lagoon earlier due to warmer waters – but then failed to find sufficient seaweed there. The problem with that is that the herring is at the beginning of the local marine food web. Less herring means less food for bigger fish, ducks, and less catch for fisherman Claas Wollna, whom we heard at the beginning of this episode. Healthy seaweed is also a real climate superhero. One square kilometer of seaweed captures twice as much CO2 as terrestrial forest and it does this 35 times faster as well. The same goes for other plants in coastal waters. Researchers in New Zealand looked at the health of kelp in a lagoon that had strong inflow of nutrients from agriculture and the city of Auckland. The found that the darkening in that lagoon caused local kelp forests to degrade and fix up to 4.7 times less carbon than they usually would. To mention it a bit in advance: we're not doomed because of Coastal Ocean Darkening. That being said though, our take-away from the diving trip with Florian Hoffmann is that Coastal Ocean Darkening does both harm biodiversity and the climate. Except for one life form that seems to handle the dark waters quite well. As Hoffmann speaks, a handful of common jellyfish floats past the boat, just a little below the sea surface. Jellyfish who consist of 95% water are particularly transparent and small, about the size of a saucer. They have a distinct advantage in the murky water. Dag Aksnes: Jellyfish don't need light to feed. It's a so-called tactile predator. That's Dag Aksnes. Dag Aksnes: I'm a marine ecologist at the University of Bergen. And I have studied mostly fjords but also the ocean. You've likely seen pictures of Norway's majestic fjords. Long and narrow, placed between steep cliffs and several hundred meters deep. At first glance the fjords appear to be lakes, but they are in fact saltwater inlets from the North Sea, mixed with some freshwater from land that gets into the fjords via mighty waterfalls. But we're moving away from the topic... After decades of research, Dag Aksnes has come to know the fjords around Bergen like the back of his hand, both above and below the water's, in the living and non-living world. Until he and his colleagues from the University of Bergen went to a fjord called Lurefjord to check up on the fish population there. They let the trawl net down into the water, started the boat's engine and set off. Dag Aksnes: We would expect, like, at maximum in half an hour to get like 100 kilograms of this fish, which is very abundant also. But, when we trawled in this field, then we actually had to cut the trawl in the water and destroy it because we couldn't have it all up on deck. Instead of a bit of fish – and after just a few minutes – the trawl net was bursting with thousands of big, orange, fluorescent jellyfish. Dag Aksnes: You can trawl them and, actually, in five minutes you can have five tons. So it's a ton per minute. The helmet jellyfish is found all over the world and that's perfectly normal. But not in such large numbers. For the whole fjord, Aksnes estimated the population of jellyfish at 50,000 tons. Or in individuals... Dag Aksnes: Ohhh (laughs). Well if it's 500 grams each, in a ton you will have 2000 and then you have 50,000 tons multiplied by 2,000. Which translates into 100 million jellyfish. But almost no other life. Dag Aksnes: And then we started wondering, why is this jellyfish here and not the fishes? Dag Aksnes: And then we saw that the water down there was very dark. Too dark for visual-hunting fish to see its prey. Meanwhile jellyfish don't need light but use their tentacles to sense prey. Less competition and warmer seas due to climate change help them to spread. Not only in the Lurefjord, which is now also known as the 'jellyfish fjord', but to a smaller extent also in many other fjords along the Norwegian coast. But the reason for the dark water in the fjords is different from the nutrient overflow in the Baltic Sea. Dag Aksnes: So actually, we got a very extended water column with coastal water containing lots of dissolved organic matter which originates from land. And then this question, of course, which we still investigate, is why has this amount of dissolved organic matter which absorbs lights increased. Dissolved organic matter. Small particles of rotten leaves or wood. It gets into the Norwegian fjords via the rivers from all over Northern Europe. And stays in there for decades before it eventually degrades. In the case of Lurefjord, it accumulates more and more due to an exceptionally narrow exit to the sea. The irony here is that the source of all this organic matter is something that we'd usually desire: more nature. Dag Aksnes: The evidence now is that this is because of increased greening in Northern Europe. [...] There are more trees now than a hundred years ago. Much more. This is partly because of change in land use. [...] The other reason is, I believe, warming and also increased precipitation over Northern Europe, which also stimulates greening. [...] More green coverage in Scandinavia and Northern Europe which produces more dissolved organic matter that enters the sea sooner or later. Think of it as a cup of tea. You pour in the water, add a tea bag and watch as the water slowly turns brown. And now think of that cup of tea as a big barrel standing in a garage building, named like a character from a Transformers movie: planktotron. We're at the Institute for Chemistry and Biology of the Marine Environment in Wilhelmshaven. That's another German harbor town – the last one, that's a promise – but this one is situated at the North Sea coast. The planktotrons are 12 large cylindrical tanks made from stainless steel and wrapped with hemp and black foil for insulation. The numbers 1 to 12 are taped on the foil with pink duct tape. Maren Striebel: We can simulate the marine environment on a smaller scale here. We can manipulate nutrients or what we did in the Coastal Ocean Darkening project was to manipulate the light. Maren Striebel is a biologist at the institute. She does research on plankton and was part of the research group of Oliver Zielinski, whom we heard earlier. Maren Striebel: We had three different levels of intensity of input of dissolved organic matter. There was definitely shading at the beginning and an impact on the primary producers, the phytoplankton. We observed a reduction in its biomass, which had an impact on the next trophical stage, i.e. the food web in the water. But then the organic matter degraded over time and the nutrients were used up, so the system returned to its orginial state at some point. The dissolved organic matter waseaten up, so to say, by organisms in the water, which subsequently cleared and brightend up. That's good news. But in another experiment Striebel and her colleagues also added sediment to the water in the planktotrons, or sand, taken from the local beach. And sand doesn't get used up by organism because, well, it's just sand, there are no useful nutrients in it like the organic matter. So the sand stays in the water. Again, think of it as a cup or glass. This time you add a teaspoon of sand and give it a good stir. The water turns murky for some time, before the sand slowly settles at the bottom of the glass. But the seas are no glass of water and the sediment in it is more than a teaspoon. Here's Oliver Zielinski again. Oliver Zielinski: Storms carry more sediment into the water and make the water murky. We will have more storms as a result of climate change. But we also have more sediment in the water because we have coastal erosion due to coastlines and construction work [in the water]. Trawlers stir up the sea ground with their heavy nets. All these things mobilize sediments and make the water cloudy. So the effect of sediment for visibility in the water is very strong. Nature's trick to keep sediment on the seabed is vegetation, like seaweed. It stabilizes the ground with its roots. If the seaweed retreats because of too little light, the seabed becomes even more unstable and the water even murkier. It's a vicious cycle, if you like. Oliver Zielinski: I rather like to tell science in positive narratives. If we manage to grow seaweed again, this will also bind sediment. The water will become clearer and we may be able to go deeper to establish even more seaweed. Speaking of positive narratives, Oliver Zielinski hardly complains as we talk. He has every reason to do so, doesn't he? I mean, people are worried about plastic in the seas or coral bleaching. But darkening water isn't getting that kind of attention. His optimism comes from the fact that darkening is already stagnating in the Baltic Sea in particular, but also in the Mediterranean and North America. In the North Sea, the water has even been brightening again since the 1980ies thanks to regulations around fertilizer use and the ban of phosphate in washing detergents, less nutrients have been entering the North Sea. But with global warming, rainfall and storms will become more extreme, which will lead to more organic matter and sediment being washed into coastal waters, Zielinski says. The best way to stop coastal ocean darkening would therefore be to limit global warming. Oliver Zielinski: Measures are being taken. But the efforts need to be increased, they actually need to be doubled, because climate change is working against us. We have to make an even greater effort to get back to the situation we had [in the coastal waters] before. That's the big picture. Back in the harbor, marine biologist Florian Hoffmanns thinks that very specific, local action is needed too. Florian Hoffmann: Well, trying to use less fertilizer and specifically for what you need. And possibly trying to keep water in the landscape, not pumping it directly into the sea, but letting it flow through a reedbed area where the washed-away nutrients can separate. Today's episode of Living Planet was researched and written by Jonas Mayer. It was narrated and edited by me, Neil King. Our sound engineer was Thomas Schmidt. To download this and past episodes of Living Planet, go to Apple podcasts, Spotify or wherever you get your podcasts. If you like what we do, make sure to hit the subscribe button. We're also available on DW's website, that's You can also find this and other great podcasts on our YouTube channel DW podcasts. Thanks for listening and sharing Living Planet with your friends and family. Living Planet is produced by DW in Bonn, Germany.
Scotsman
29-05-2025
- Health
- Scotsman
Why the food we eat will determine the future of life on Earth
Modern humans' diets are pushing the natural world towards a dangerous breaking point Sign up to our daily newsletter – Regular news stories and round-ups from around Scotland direct to your inbox Sign up Thank you for signing up! Did you know with a Digital Subscription to The Scotsman, you can get unlimited access to the website including our premium content, as well as benefiting from fewer ads, loyalty rewards and much more. Learn More Sorry, there seem to be some issues. Please try again later. Submitting... Sometimes, it hits you in the quiet moments – a walk through a once-bustling woodland now eerily still, the Buddleja 'butterfly' bush with no butterflies, or the absence of bees in a summer garden. The signs are all around us: nature is in trouble. As World Environment Day approaches, I find myself thinking not just about the planet, but about the choices we make every day, especially what we eat. Because behind every meal lies a story, and right now, too many of those stories are ones of loss. Advertisement Hide Ad Advertisement Hide Ad From the depths of the oceans to the peaks of the highest mountains, life on Earth has flourished for billions of years in breathtaking diversity. Wonderfully diverse civilisations have evolved, powered by an abundance of natural riches. The world is now home to more than eight billion people and a multitude of different plants and animals, all with their part to play in the complex web of life. Buying free-range food is one way that we, as consumers, can make a real difference (Picture: Matt Cardy) | Getty Images Huge declines in mammals, birds and fish Yet nature is now in emergency mode and time is running out. To keep global warming below 1.5 degrees Celsius this century, we must halve annual greenhouse gas emissions by 2030. Without action, exposure to air pollution beyond safe guidelines is expected to increase by 50 per cent within the decade and plastic waste flowing into aquatic ecosystems is set to nearly triple by 2040. In the last 50 years, according to WWF's Living Planet report , the total number of mammals, birds, reptiles, amphibians and fish has declined by 73 per cent. It's no exaggeration to say that what happens over the next five years will determine the future for life on Earth. Advertisement Hide Ad Advertisement Hide Ad And the primary reason for all this destruction? Our food. Planet-wide, the way we feed ourselves has become a dominant activity, affecting wildlife and the natural ecosystems on which our existence depends. Nearly half the world's habitable land surface and most human water use is devoted to agriculture. Ghost food waste Industrial agriculture – factory farming – is the most damaging. More than 80 billion farmed animals are produced for food every year, two-thirds of them on factory farms. Before factory farming, animals were out on pasture, turning things we can't eat, like grass, into things we can eat in the form of meat, milk and eggs. Now confined to cages, barren warehouses, or feedlots, they are fed on food crops like corn, wheat, and soya which could otherwise have fed billions of hungry people. This creates ' ghost food waste ', where crops that could alleviate hunger are squandered. The fact is that factory farmed animals are hugely inefficient at converting grain into meat or milk. Much of the food value is lost, making it the biggest single area of food waste on the planet. Advertisement Hide Ad Advertisement Hide Ad But the harm doesn't end there: animal agriculture is responsible for more greenhouse gases than all of the world's planes, trains and cars combined. Yet the global farmed animal population is expected to continue to grow, further stepping up the pressure on a natural world in steep decline. Chemical-doused monocultures As agriculture expands at the expense of dwindling forests, wildlife disappears. This happens even more so when farming and nature part company as with industrial animal agriculture. In this way, meat production has become just another industry, churning out raw materials in a way that is commonly presented as efficient but which, in fact, is grossly wasteful. We seemed to have switched our focus from feeding people to the pursuit of commodity production at any cost. More than half of all the world's food now either rots, is dumped in landfill, or feeds those long-suffering, imprisoned animals. Whole landscapes have been swept away by monocultures – vast, prairie-like carpets of uniform crops. Birds, bees and butterflies, along with the insects and plants they feed on, are in decline. Chemical fertilisers and pesticide sprays have replaced time-honoured natural ways of keeping soil fertile and problem bugs at bay. Advertisement Hide Ad Advertisement Hide Ad Farmed animals have been disappearing from fields and into confinement. Egg-laying hens in battery cages, pigs in narrow crates or barren pens, chickens for meat growing so fast that their legs can barely support their outsized bodies. Nature has been replaced by a horror show. More than enough food for all So, how did this happen? Well, part of the answer is that the food system has become hijacked by the animal-feed industry. Today, more than one-third of the entire global cereal harvest and nearly all of the world's soya is devoted to feeding industrially reared animals – food enough for more than four billion extra people. Paradoxically, we still hear talk of looming global food crises. Yet, the fact that there's already more than enough food for everybody is routinely ignored. The planet is now at a dangerous tipping point but it is not too late to prevent more destruction. What we put on our plate has never mattered more. Eating more plants and choosing organic, pasture-fed or free-range meat, milk, and eggs really can make a big difference for the future of animals, people, and the countryside. Advertisement Hide Ad Advertisement Hide Ad This World Environment Day, let's recognise that the power to change course lies in our hands. By rethinking what we eat and how it's produced, we can help restore balance to our planet.
WIRED
05-05-2025
- General
- WIRED
How Mexico's Fishing Refuges Are Fighting Back Against Poaching
May 5, 2025 8:00 AM Following inaction from the government, fishing communities and conservationists are taking it upon themselves to set up and monitor no-catch zones to combat species depletion caused by overfishing. Community divers and monitors enter the Celestún Fishing Refuge Zone. Photograph: Geraldine Castro It has been two hours since the divers left the coast behind. As they reach their designated GPS points in the Gulf of Mexico, their boats' engines go from roaring to whispering. In pairs, they enter the Celestún Fishing Refuge Zone, one of the largest in Mexico. Their ritual is absolute: put on fins, adjust vests and hoses, clean visors, and load oxygen tanks and weights. For the next few minutes, their lives depend on having carefully prepared their dives to this place of hope. They are here seeking to restore fisheries in decline or on the verge of collapse. This refuge, a no-catch zone established in 2019, covers 324 square kilometers and is monitored by the Yucatán Coast Submarine Monitoring Community Group, a group of community divers and fishers, who are supported by personnel from the Mexican Institute for Research in Sustainable Fisheries and Aquaculture (IMIPAS) and the civil association the Community and Biodiversity (COBI). Their methodology mixes local knowledge with scientific rigor. The problem they face is a global one: Overfishing and environmental degradation are destroying the biodiversity of the oceans, with many countries lacking the will or resources to combat the problem. In 2024, as sea-surface temperatures broke all-time records, the Worldwide Fund for Nature's Living Planet report showed that, over the past 50 years, marine populations worldwide have declined in size by 56 percent. Over a third of current marine populations are overfished. In Mexico, more than 700 marine species are fished in 83 fisheries, which support 200,000 Mexican families. Analysis of Mexico's National Fishing Charter by IMIPAS indicates that 17 percent of the country's fisheries are deteriorated, 62 percent are being exploited at their maximum sustainable level, and 15 percent have no information on their state. When the conservation nonprofit Oceana analyzed the same data, it found that 34 percent of Mexico's fisheries are in "poor condition,' says to Esteban García Peña, Oceana's coordinator of research and public policy. Part of the problem is that, under Mexican law, no one is obligated to look after the health of the country's fisheries; Mexico's General Fisheries Law doesn't obligate the government to take on this responsibility. Oceana has petitioned to change this, and in the face of legislative disinterest, even filed an injunction in 2021 against the Congress of the Union, alleging violations of human rights, such as access to a healthy environment and food. This inspired a proposal to revive Mexico's deteriorated fishing zones, only for it not to be analyzed or approved by Congress, and the project was frozen. In 50 years, the world has lost 56 percent of its marine populations. Photograph:Faced with this uncertainty, communities have taken things into their own hands. Although the government isn't obliged to protect and revive the country's fisheries, people can request for it set up refuge zones to conserve and repopulate marine ecosystems. And so today, there are refuges in Baja California Sur, Quintana Roo, and Campeche, totaling more than 2 million hectares and benefiting, directly or indirectly, 130 species. 'When the first proposal was put forward, it seemed crazy,' says Alicia Poot, an IMIPAS researcher and head of the Regional Center for Aquaculture and Fisheries Research in Yucalpetén. 'Some people think it's closing the sea, but it's not. It is working an area in a sustainable way, with community oversight.' The Limits of Abundance The day before the monitoring begins, the Celestún team gathers under a large palapa. Jacobo Caamal, COBI's scientific diving expert, reviews the plan for the next few days. He jokingly gives practical advice, using coconuts to show how to measure sea cucumbers and sea snails. They talk about sea cucumbers because, although it is not part of Mexican gastronomy, its fishing has brought a lot of profit to this coast. In the Chinese market these creatures can fetch more than $150 per plate. The hype over the echinoderm has driven practices that are harmful to the ecosystem and to the fishermen's health, such as diving using a hookah , a makeshift diving machine that runs on gasoline and pumps oxygen down a tube to divers below the surface. Sanitary towels sometimes stand in as an oil filter, while mint tablets are taken to mitigate the taste of gas. In Celestún, nobody denies the risk of diving with this machine. Many know someone who has had an accident or died from decompression. Until 2012, this area had cucumbers in abundance, but violation of its closed seasons brought the species to the brink of extinction. Divers started going deeper and deeper to hunt them. The situation became untenable. Then, a group of fishermen asked IMIPAS researchers for help to establish an area where the sea could have a chance to recover. Overfishing has depleted other species here too. Leonardo Pech, founder of the refuge and captain of one of the boats during the monitoring trip, has been accompanying IMIPAS researchers for years to evaluate the state of marine species. A couple of decades ago, he says, scallops were fished until they were spent. It was intense and unregulated, Pech recalls. The fishermen knew they had to let the species recover, he says, but not everyone respected this need. Some time later, the same thing happened with the Moorish crab. 'They would cut off both claws. Everywhere you walked by, you'd see dead crab breasts. It was spent.' Then fishing of grouper began. 'There were plenty, big. Now it's gone down and the juvenile is this size,' Pech says, showing its small length with his hands. Predation then reached the octopuses. New fishermen opted to use illegal compressors to dive instead of relying on artisanal fishing, which is done with wooden sticks, string, and bait. With this traditional method, females with young do not take the bait, and that protects the species from overfishing. But diving sweeps up octopuses evenly. In 2023, over 20,000 tons of octopus were caught in Yucatán. The collapse of fisheries doesn't just result in fewer animals and smaller sizes. It also pushes fishermen to go further and further out into the ocean sea and spend more days at sea. They even make unregulated adjustments to their fleet. 'They raise their boats in search of more stability in deeper places, they add huts,' says Poot. Keeping profits higher than their operating costs is a necessity, even if this puts fishermen's lives at risk—for instance when getting caught in storms in in homemade boats. Nancy Gocher, coordinator of Oceana's campaign team, explains that the depletion of marine resources—while partially being driven by overfishing—at the same time violates the fishermen's right to work, their food sovereignty (more than 3 billion people obtain their nutrients from the sea), their identity, and their right to a healthy environment. They are also victims of forces outside of their control. "Fishing communities receive the first impact of the inclemencies aggravated by climate change,' she says. Before applying for the refuge in Celestún, local fishermen and researchers had many conversations. When they saw the fisheries information compiled by the Regional Center for Aquaculture and Fisheries Research, they realized that it was not only the cucumber that needed protection. Species such as red grouper ( Epinephelus morio ) and red octopus ( Octopus maya ) were also listed as overexploited or in decline. So the community agreed to try replenish populations of red grouper, Caribbean lobster ( Panulirus argus ), Mayan octopus, and sea cucumber. Within the delimited area of the refuge, artisanal octopus fishing and the capture of king mackerel ( Scomberomorus cavalla ), Atlantic Spanish mackerel ( Scomberomorus maculatus ), and great barracuda ( Sphyraena barracuda ) is allowed between October and February using 'trolling'—pulling a baited hook behind a boat; diving, sport fishing, and domestic consumption of other species is prohibited. Against the 'Race for Fish' Josué Canul is one of the people under the palapa. 'I was one of the first divers, known for being a poacher fisherman. I have been one of the biggest predators,' he says. For 30 years, Canul dived with hookahs . 'I was their hater,' he says of conservationists—now he the refuge's president. Three years ago, he didn't believe in the project, but he went to one of its meetings. 'I was going to fight,' he admits. But first, he sat down to listen. That day he understood his mistake: it was not a forbidden site, but a workspace. The area was new, and much remained to be done, but the idea captivated him for two reasons: the loss of marine abundance, which he was witnessing, and the promise of a better future. 'I had always wanted, in unison, for the community to say: we don't fish in this area so that it will reproduce and leave some here for us.' In the past, it was said 'that in Celestún they burned your boats, that the most terrible and furtive fishermen lived there,' says Mariana Suasnávar, a climate change specialist at COBI. To think that this community would be the first in the state to take such measures to recover the fisheries was far-fetched. Today, the idea is backed by 66 leaders, men and women. On the left, Josué Canul; on the right, Captain Ángel Novelo. Photograph: Geraldine Castro Dismantling illegal fishing is difficult. Canul says that fishermen justify being poachers because it feeds their families. 'Since we were kids, we have the culture that the more you catch, the more you have. We were never taught to take care,' he says. Andrea Saénz, a marine biologist and environmental economist at the Colegio de la Frontera Sur, calls this phenomenon 'the race for fish,' in which 'whoever gets there fastest gets the treasure.' In her view, this extractivist approach to the sea occurs because there is open access, which leads to thinking: 'If I don't take it out, someone else is going to do it.' Poot points out that fishing refuge zones are a management tool, so that the communities return little by little to good practices. 'That piece motivates them to take care, to teach the new generations how fishing should be, because today it has been distorted,' she says. Early on the dock, the fishermen watch the monitoring group leave. Photograph: Geraldine Castro It's expected that a well-kept fishing refuge will result in larger organisms, greater abundance of fish, and more diversity of species. A desired effect is overflow—that is, for these benefits to be seen beyond the borders of the protection site. Poot explains that, to measure this, it is crucial to establish a baseline of how the site is at the beginning and implement a constant monitoring program. 'If five years go by and you don't notice results, it is possible to extend it longer. Not all areas are equally resilient.' Saénz says there is evidence of recovery with this strategy, but evaluating benefit takes time. 'Experiments to evaluate that the cost of not fishing is offset by larval dispersal are scarce,' she says. She collaborated with COBI on a study on Isla Natividad, off the coast of Baja California Sur, where they collected data over ten years and found that lobster fishing was good at the boundaries of the reserve set up there. Participatory Underwater Science On the day of the monitoring, the divers are dropped on their backs into the sea and descend. For 30 minutes, a buoy tracks their location. Some pairs practice wandering dives, others follow a transect, a sampling line, to systematically collect data. Some describe the type of seabed and its contents every 50 centimeters for 50 meters; others identify, count, and indicate the size of fish. The invertebrate biometry team collects snails and cucumbers to measure them on the boat and, underwater, they record lobsters, octopus, and other organisms. Everyone notes whether the sampling site is inside or outside the refuge, key information for future comparisons. 'It's like taking a picture of the sea,' says Suasnávar. Measuring a sea cucumber. Photograph: Geraldine Castro Esther Yerves, a lawyer and part of a fishing family, returns soaking wet to the boat with a smile: 'It's like entering another world,' she says. She joined the project after seeing the decline of the octopus and today is treasurer of the refuge and a member of the Yucatán Coast Submarine Monitoring Community Group, where 14 women and 12 men from different Yucatecan communities participate. She learned to dive to see with her own eyes if the effort was worth it, and to make her voice heard in the decision-making process. The monitoring group is made up of people involved in the fishing chain with the support of organizations such as COBI, agencies such as IMIPAS, the Secretariat of Sustainable Fisheries and Aquaculture of Yucatán, and the National Commission of Natural Protected Areas. Members have received certifications in open water scuba diving, first aid, and species identification methodologies designed by IMIPAS and COBI. Their work helps to expose the results of sustainable management and to recognize if there is anything to adjust in the management of the area. Esther Yerves, one of the divers who cares for the Celestún fishing refuge. Photograph: Geraldine Castro The Blue Economy Is Also Inland When the team returns to land, they eat, bathe, and rest for a while. They get gas for the next trips, prepare food, and digitize their log sheets. Data capture takes place in a small room with air conditioning, cake, and coffee. From the log sheets jump the marine characters: mackerel scad ( Decapterus macarellus ), yellowtail snapper ( Ocyurus chrysurus ), canané. If someone mispronounces the Latin, they gently correct each other, rehearsing the name out loud with laughter. A copy of Paul Humann's Reef Creature Identification , considered a must-have for divers, biologists, and marine life lovers, is passed from hand to hand, with team members pointing out the species they have already found and those they would like to see soon. In the evenings, Caamal, the scientific diving expert from COBI, sits among the mosquitoes and the noise of filling tanks. There he explains to me that the success of the refuge goes beyond the biological aspects. 'Monitoring biomass and fish is useful, but if the community doesn't participate or know about the project, it loses meaning,' he says. A research article he coauthored emphasizes that protected conservation areas are most effective when combining technical expertise, Western science, and participatory science with local fishermen. On land, they seek to empower fishermen, reduce the gender gap in the local economy, diversify voices in decision making (in Celestún there is a committee of women and another of young people), and strengthen community pride and the defense of the territory. Some groups are organizing against predatory tourism or the care of other coastal ecosystems, such as dunes or mangroves. Alesxia, an experienced diver from Punta Allen in neighboring Quintana Roo, helps with monitoring. Photograph: Geraldine Castro When Canul joined the project, there were pending issues that could not be put off: surveillance and monitoring. But there was no money. Canul is a restless person—his colleagues say that even underwater he keeps talking. It was only a few months after joining the refuge team that he assumed the presidency. Priscila and Maritza, the youngest of the Yucatán monitoring group. Photograph: Geraldine Castro To raise funds, the Celestún group organizes festivals, but now they have won a grant from the United Nations Development Program (UNDP). As a result, they are about to integrate electric motors into their work. Alondra Ramírez, UNDP Mexico Small Grants Programme associate in charge of the energy projects portfolio, explains that, using electric mobility will help reduce the environmental impact of surveillance, monitoring, and fishing. Left: Esther Yerves, ready to dive. Right: Stowing away equipment. Photograph: Geraldine Castro Missing Eyes at Sea In addition to the effort to obtain scientific data, fishermen monitor the area against poaching and look for ways to finance this. Since 2019, there has been no federal budget allocated to fisheries management in Mexico, including the operation of these zones. 'Your budget speaks of your priorities. In the last six-year term, fishing was priority zero. Many of the things that have happened are thanks to the management and organization of civil society,' stresses Saénz. Gocher of Oceana points out that many of the obstacles faced in marine conservation are due to the lack of social fabric. It's known locally who is fishing illegally. 'That they have to ask them not to do it implies a community conflict, but it also opens the opportunity to restore the social fabric. When the community sees results—that there are more resources, that forms of economy are created, such as tourism, that are more sustainable and at their pace—they begin to take care,' Gocher says. 'There are many fishing refuge zones and protected marine areas in which fishermen and fisherwomen make vigilance committees to make sure that fishing is done legally; they take care of everyone's resources,' says Gocher. 'In Mexico, 75 percent of the fisheries are exploited without management plans, which puts the sustainable development and wellbeing of the communities at risk.' Many vigilance groups begin by financing activities out of their own pockets and, as they organize, they look for ways to be reimbursed. For three days, COBI members supported the monitoring. Photograph: Geraldine Castro Against poaching, the refuge team knows that they are swimming against the current, that they must deal with the frustration of taking care of a resource that others steal at night. They know they are at risk for pointing out those who break the rules, even if they are their neighbors. 'Many times we look like clowns when we do surveillance, catch people who do something illegal and the law does nothing to them,' says Canul. During the monitoring, one of the captains notices a boat on the horizon and deduces that they are coming from illegal fishing. He picks up the radio and asks the others what to do; they decide not to interrupt the monitoring. 'We have little data to know how to fight illegal fishing. Inspection and surveillance in Mexico are not robust,' Gocher says. Analysis from Oceana has revealed a reduction in surveillance patrols by the National Commission of Aquaculture and Fisheries. In 2023, 332 maritime patrols and 99 land patrols were recorded, the lowest figures in 15 years. 'There is no information on what happens when someone is caught or a vessel or product is seized. After the complaint, almost no one knows what happens. There is opacity in the data and a high level of impunity,' Gocher says. Mexico is in the process of establishing 14 fishing refuge zones, which would total more than 100,000 hectares of conservation in seven states—mainly in Sonora and Yucatán. This year the peninsular state added two more refuges, one in El Cuyo and another in Chabihau; months ago, the Actam Chuleb refuge was made official, which had been operating as a community marine reserve for years. Due to the growing interest in the refuges, the creation of a National System of Fishing Refuge Zones has been proposed. A consultancy, financed by the World Bank and the French Development Agency, in coordination with the Mexican government, reviewed the idea. Suggestions include incorporating fishing goals as part of the National Development Plan, strengthening community management, creating a national fund, and providing legal security for coastal communities to manage their territory. The vision for recovering the productivity of the sea, says Saénz, is an example of 'coupled scales.' First, work with those who access a maritime territory, then see how they connect with their neighbors, then with currents, and with land-based activities. 'You need a complete understanding of these phenomena.' What is impossible, she assures, is to try to recover a species without listening to the fishermen. Juan Pech has seen marine beauty and also a damaged sea. The diver explains his commitment with an anecdote. Years ago, the man who taught him commercial diving told him where to go to find fish. Juan followed his instructions, but came to a dead site; nothing his teacher described was still there. If he ever has children, he says he doesn't want to tell them about a sea they can't see. This story originally appeared on WIRED en Español and has been translated from Spanish.
