Hunting, Fishing Cause Dramatic Decline in Amazon River Dolphins
By Claire Asher
Populations of two species of river dolphin in the Amazon are halving every decade, according to the results of a twenty-two year survey.
The Amazon rainforest is home to the Amazon river dolphin, or Boto (Inia geoffrensis) and the Tucuxi (Sotalia fluviatilis). But the results of a long-term study published in PLoS ONE show that both of these once abundant aquatic mammals are now in rapid decline in the Brazilian Amazon, likely due to hunting and fishing.
Vera da Silva from the Instituto Nacional de Pesquisas da Amazônia, in Manaus, Brazil, and colleagues conducted monthly surveys of river dolphins in the Mamirauá Reserve in Amazonas state between 1994 and 2017. They found steep declines in both species over the last two decades, with Boto populations halving every ten years and Tucuxi every nine years—some of the most severe declines seen in cetaceans since the moratorium on commercial whaling came into effect in the 1980s.
"Data from over 22 years of monitoring … revealed a precipitous decline of [Boto] in the last two decades," said da Silva. "Before 2000, the population was quite stable."
Boto Amazon river dolphins (Inia geoffrensis). According to researchers, Boto populations are halving every ten years in the study area. Image courtesy of Associação Amigos do Peixe-Boi (AMPA)
The IUCN Red List categorizes both species as "data deficient," meaning that there is insufficient information to determine their conservation status; the murky waters of the Amazon river make them difficult to study. But the authors say that applying the IUCN Red List Criteria to their data would result in the species being listed as Critically Endangered, having suffered greater than 90 percent declines since 2000 (the Boto declined by 94 percent, and the Tucuxi by 97 percent in the study area, according to the researchers).
"In my opinion, the real importance of this paper is it shows that populations in their study site have a negative growth trend, and [the research] does it with quantitative information," said Elizabeth Campbell, a conservation scientist at ProDelphinus Peru, a conservation NGO based in Lima, Peru who was not involved in the current research. Although other studies have attempted to estimate population trends for these enigmatic creatures, "this is the only study that has had a constant presence for 20+ years, through different seasons, in [the same] area," she said.
Finding these illusive creatures requires patience and an eagle eye: "The Botos and Tucuxis come to the surface to breathe every 1-2 min," explained da Silva, which provides a brief window of opportunity to spot the creatures, before they disappear back into the muddy waters.
The scientist said that when they first began their surveys, the dolphins were plentiful. "When we started our work with these dolphin populations in 1994, we were astonished by the number of animals in the area," da Silva said. "It was impossible to go out by boat without seeing dolphins."
A Boto surfaces in the Marañón River, Peru. Difficult to detect in Amazonia's murky waters, both species are listed as "Data Deficient" by the IUCN. But researchers maintain that if region-wide surveys were conducted both species would end up being listed as Critically Endangered. Clara Ortiz-Alvarez
Over the years, the team not only counted the numbers of dolphins, it also captured and marked some, allowing the researchers to identify individuals in the field. As time passed, they started noticing huge scars from harpoon and machete injuries on the river dolphins they caught. Interviewing local fishermen confirmed the team's suspicions: "Botos were being hunted for bait, and in large numbers," said da Silva.
Around the turn of the millenium, catches of commercially important catfish known as Piracatinga or Mota (Calophysus macropterus) in Colombia were shrinking, so new fisheries began to spring up in Brazil to meet market demand.
By 2011, subsistence fishermen had shifted toward becoming commercial fishermen in the Brazilian state of Amazonas, as they hauled in 4.4 million kilograms (9.7 million pounds) of catfish each year. Part of their success could have been due to the bait they used. "They started using caiman meat," said da Silva, but soon found that Boto carcasses from entanglement with fishing gear were a more effective bait. "Dolphin meat lasted longer and [the catfish] preferred Boto carcasses," she said.
The supply of accidentally-killed Botos was soon exceeded by demand, and the fishermen started actively hunting them.
River dolphin leaping. Amazon river dolphins had been considered resilient compared to their Asian relatives. But this latest study shows that South America's river dolphins may also be headed toward oblivion unless action is taken to reduce hunting, fishing and other pressures on both species.F. da Silva VM
The dolphins were abundant at the time, and their high densities in small river inlets and bays, combined with their natural curiosity, made them easy targets, da Silva explained. The Brazilian government placed a five-year moratorium on fishing for piracatinga in 2014, but the practice still continues illegally.
Botos are found throughout both the Amazon and Orinoco river basins. In the wet season, the dolphins leave river channels and swim out into the flooded forests to search for prey among the roots and trunks of partially submerged trees.
Although legally protected in the Amazon, poor enforcement has meant that the species is still routinely entangled in fishermen's nets and gear, as well as deliberately hunted for fat and blubber. Some fishermen see the dolphins as a nuisance—competing with them for fish and damaging their equipment—and so kill them intentionally. "Fisherman do not like Botos because they damage the fish and the fishing gear," said da Silva.
In contrast to Boto, the survey showed that Tucuxi have been declining consistently since at least the mid-1990s. Unlike the Botos, Tucuxi don't enter the flooded forests to feed, but instead stick to the main river channels and tributaries. The species is smaller and faster-moving than the Boto, and is generally considered friendly and not a pest by local fishermen, making it less vulnerable to deliberate hunting. However, gear entanglement remains a serious threat, particularly because fishing nets are often set at the mouths of river channels where the Tucuxi tend to congregate.
Boto swimming in the Rio Amazonas, Brazil in 2016. A lack of political will, drastic cuts to the Brazilian environmental ministry budget, and continued illegal dolphin hunting and fishing are putting these aquatic mammals at risk.Martha de Jong-Lantink on Visualhunt.com / CC BY-NC-ND
The decline of both species is significant for aquatic ecology. River dolphins are a key part of the Amazonian ecosystem—Botos are known to feed on 43 different species of fish, most of which live near the river bottom, while Tucuxis feed on at least 28 species, mostly small schooling fish found higher in the water column. Many of these fish are commercially exploited, too, putting the dolphins in direct competition with local fishermen.
"The takeaway message for me is that fisheries interaction with river dolphins is probably the most significant threat these species face," said Campbell, adding that "populations are decreasing faster than we could expect."
Mamirauá Sustainable Development Reserve, where the study was conducted, is a 4,300 square-mile (11,000 square-kilometer) protected area—one of the largest in the Brazilian Amazon. Within the reserve, where commercial fishing is banned, mortality of dolphins is primarily the result of accidental deaths from subsistence fishing. However, some Botos travel up to hundreds of kilometers, straying outside the reserve where they may encounter other threats, including direct hunting, commercial fishing gear and pollution from agricultural run-off and mining.
One danger: toxic mercury, often used in mining to separate gold from soil and rock, accumulates in river sediments and can cause problems for top predators, like river dolphins, that consume large quantities of pollutants in the fish they prey on. The mercury bio-accumulates in increasing, eventually deadly, amounts in the dolphins' fat.
Amazon river dolphins had been considered resilient compared to their Asian relatives, the endangered Ganges river dolphin (Platanista gangetica) and the critically endangered Baiji (Lipotes vexillifer), which many conservationists believe may be extinct in the wild. Da Silva and colleagues' latest study shows that South America's river dolphins may also be headed toward oblivion.
Tucuxi swimming. Brazil's struggling economy means that fishermen are likely to try to increase their catches, even if that means illegally using dolphins for bait, or killing them either by accident or intentionally.Mike LaB on Visualhunt / CC BY-NC-ND
If Amazon basin dolphins are to survive, the Brazilian government needs to take the first step of strengthening existing protections and improving enforcement, da Silva said. "Controlling the fisheries catching catfish and preventing fishermen setting nets at the entrances of rivers, lakes and channels," would be a good start, she said.
Implementing dolphin protections and preventing illegal hunting in the flooded forests of the Amazon would be challenging, but is possible, da Silva said. But Brazil's environment ministry has seen draconian budget cuts (51 percent in 2017 alone) under the Temer administration, so it lacks the staff, equipment and fuel needed to monitor remote Amazonian regions. And as in many countries, there is currently a lack of political will to pass and enforce strong environmental legislation. Meanwhile, Brazil's struggling economy means that fishermen are likely to try to increase their catches, even if that means illegally using dolphins for bait, or killing them either by accident or intentionally.
"Fisheries in the Brazilian Amazon are not well controlled and quantified," da Silva said. And there is no sign that that reality will change soon.
Reposted with permission from our media associate Mongabay.
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What Is PTSD?<p><a href="https://theconversation.com/veterans-refugees-and-victims-of-war-crimes-are-all-vulnerable-to-ptsd-130144" target="_blank">PTSD</a> can occur when someone is exposed to extreme exposure traumatic experience. Typically, the trauma involves a threat of death, serious injury, or sexual violence. Along with war veterans, it happens to refugees; to victims of gun violence, rape and other physical assaults; and to survivors of car accidents and natural disasters like earthquakes or tornadoes.</p><p>PTSD can also happen by witnessing trauma or its aftermath, often the case with <a href="https://www.psychiatry.org/patients-families/ptsd/what-is-ptsd" target="_blank">first responders</a> and <a href="https://www.psychologytoday.com/us/blog/the-many-faces-anxiety-and-trauma/202006/invisible-wounds-the-frontline-heroes" target="_blank">front-line workers</a>.</p><p>All this adds up to tens of millions of Americans. Up to 30% of combat veterans and first responders, and 8% of civilians, <a href="https://www.ptsd.va.gov/professional/treat/essentials/epidemiology.asp" target="_blank">fulfill the diagnostic criteria for PTSD</a>. And that criteria is not easily met: symptoms of PTSD include nightmares, flashbacks, intrusive trauma memories, difficulty sleeping, avoidance of reminders of trauma, negative emotions, and what we call "hyperarousal symptoms."</p>
Fireworks Can Trigger Flashbacks<p>Hyperarousal, a core component of PTSD, occurs when a person is hyper-alert to any sign of threat – constantly on edge, easily startled and continuously screening the environment.</p><p>Imagine, for instance, stepping down the stairs in the dark after hearing a noise; you're worried an intruder might be downstairs. Then a totally unpredictable loud sound explodes right outside your window.</p><p>For people with PTSD, that sound – reminiscent of gunfire, a thunderstorm or a car crash – <a href="https://theconversation.com/veterans-refugees-and-victims-of-war-crimes-are-all-vulnerable-to-ptsd-130144" target="_blank">can cause</a> a panic attack or trigger flashbacks, a sensory experience that makes it seem as if the old trauma is happening here and now. Flashbacks can be so severe that combat veterans may suddenly drop to the ground, the same way they would when an explosion took place in combat. Later, the experience can trigger nightmares, insomnia or worsening of other PTSD symptoms.</p><p>Those of us who set off fireworks need to ask ourselves: Are those few minutes of fun worth the hours, days, or weeks of torment that will begin for some of our friends and neighbors – including many who put their lives on the line to protect us?</p>
Who Else Is Affected?<p>Millions of others, though not diagnosed with PTSD, may similarly be affected by fireworks. <a href="https://adaa.org/about-adaa/press-room/facts-statistics" target="_blank">One in five Americans</a> have an anxiety disorder, many with symptoms of hyperarousal. Also impacted are those with autism or developmental disabilities; they find it difficult to cope with the noise, or just the drastic change from life routines. Then there are people who have to work, holiday or not: nurses, physicians and first responders, who have to be up at 4 a.m. for a 30-hour shift.</p><h3>How to Reduce the Negative Impact</h3><p>There are ways to reduce how fireworks affect others:</p><ul><li>For those with PTSD, the unexpected nature of fireworks is probably the worst part. So at least make it as predictable as possible. Do it in designated areas during designated times. Don't explode one, for instance, two hours after the designated time window. And avoid setting them off <a href="https://www.theguardian.com/society/2018/jul/04/fireworks-ptsd-fourth-of-july-veterans-shooting-survivors" target="_blank">on the 3rd</a>. People are less prepared then.</li><li>If you're aware that a veteran or trauma survivor lives in the neighborhood, move the noise as far as possible from their home and give them prior warning. Consider putting a sign in your front yard noting the time you'll set the fireworks.</li><li>Remember, it doesn't have to be super loud to make it fun. Consider using <a href="https://thehill.com/opinion/energy-environment/504964-its-time-for-silent-fireworks" target="_blank">silent fireworks</a>. And you don't have to be the one who lights the fireworks. Simply enjoy watching while your city or township does it safely.</li></ul>
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By Jeff Berardelli
For the past year, some of the most up-to-date computer models from the world's top climate modeling groups have been "running hot" – projecting that global warming may be even more extreme than earlier thought. Data from some of the model runs has been confounding scientists because it challenges decades of consistent projections.
International Effort to Evaluate Climate Models<p>For the past 25 years the international community has been evaluating and comparing the world's most sophisticated climate models produced by various teams at universities, research centers, and government agencies. The effort is organized by the World Climate Research Programme under the United Nations World Meteorological Organization.</p><p>Climate models are complicated computer programs composed of millions of lines of code that calculate the physical properties and interactions between the main climate forces like the atmosphere, oceans, and solar input. But models also go a lot further, incorporating other systems like ice sheets, forests, and the biosphere, to name a few. The models are then used to simulate the real-world climate system and project how certain changes, like added pollution or land-use changes, will alter the climate.</p><p>Every few years there is a new comprehensive international evaluation called the Coupled Model Intercomparison Project (CMIP). In the sixth such effort, known as CMIP6 and now under way, experts are reviewing about 100 models.</p><p>Information gleaned from this effort will act as a scientific foundation for the U.N.'s Intergovernmental Panel on Climate Change (IPCC) next major assessment report, scheduled for release in 2021. The goal of the report – the sixth in 30 years – is to inform the international community about how much the climate has changed, and, importantly, how much change can be expected in coming decades.</p>
A Conundrum Emerges<p>Over the past year, the CMIP6 collection of models being reviewed threw researchers an unexpected curveball: a significant number of the climate model runs showed substantially more global warming than previous model versions had projected. If accurate, the international climate goals would be nearly impossible to achieve, and there would be significantly more extreme impacts worldwide.</p><p>A foundational experiment in every report addresses "sensitivity": If you double levels of carbon dioxide (CO2) that were in the air before the Industrial Revolution, how much warming do the models show? This doubling is not expected for a few more decades, but it is a quick way to communicate the critical role of greenhouse gases in changing the climate.</p><p>The amount of CO2 in the atmosphere has increased by 35% since the 1800s because of the burning of fossil fuels. As a result, global temperatures have already increased by more than 2 degrees Fahrenheit.</p><p>In the first IPCC assessment report, published in 1990, the answer to that question about the impact of doubling carbon dioxide gave a fairly wide range of results – between 2.7-8 degrees F of global warming. Since then, four more assessments issued six to seven years apart reached nearly the exact same conclusion on sensitivity.</p><p>But that sensitivity may, for the first time, change significantly in next year's assessment. Why? Because starting last year, numerous models in the CMIP6 collection displayed even bigger spikes in temperature upon doubling of CO2 concentrations. We're in serious trouble if the climate sensitivity falls in the mid or upper range of the previous assessments. But if the new, higher estimates are correct, the impacts on civilization would be catastrophic.</p>
In the above CarbonBrief interactive visualization, the bars offer a comparison in the range of sensitivity in the CMIP5 models (gray) and CMIP6 models (blue).
New and Encouraging Evidence Is Emerging<p>At first, scientists were uncertain whether the new model runs were on to something, so the international modeling community dug in to produce multiple studies. The results are not yet conclusive, but a gradual collective sigh of relief seems to be materializing.</p><p>"Evidence is emerging from multiple directions that the models which show the greatest warming in the CMIP6 ensemble are likely too warm," explains Dr. Gavin Schmidt, director of NASA's Goddard Institute for Space Studies.</p><p>For example, <a href="https://www.earth-syst-dynam-discuss.net/esd-2020-23/" target="_blank">a study</a> released April 28 evaluated the past performance of the models making up the CMIP6 ensemble. The team assigned weights to each model based upon historical performance of their warming projections, weighing the poorer performing models less. By doing so, both the mean warming and the range of warming scenarios in the CMIP6 ensemble decreased, meaning the warmest models were the ones with weaker historical performance. This result supports a finding that a subset of the models are too warm.</p><p>That conclusion is supported by another new study evaluating one particular model – the Community Earth System Model (CESM2) – that showed greater warming. Using that model, the researchers simulated the climate in the early Eocene era, about 50 million years ago, when rainforests thrived in the Arctic and Antarctic. The CESM2 simulated a historical climate that seems way too warm compared with what is known about that era from geological data, indicating that the model is likely also too warm in its future projections.</p><p>Two other recent studies of the CMIP6 models being evaluated use clever analysis methods to <a href="https://www.google.com/url?q=https://www.earth-syst-dynam-discuss.net/esd-2019-86/&sa=D&ust=1589209938203000&usg=AFQjCNHYwFB-1KqndGfJ4sXdrrm9DpbLaQ" target="_blank">narrow the range</a> of future warming projections and also <a href="https://www.google.com/url?q=https://advances.sciencemag.org/content/6/12/eaaz9549&sa=D&ust=1589209938203000&usg=AFQjCNEhKY1YZ19qgjSZ_hJM14JmzqXOXw" target="_blank">reduce the projected warming</a> of the CMIP6 models by 10 to 15%.</p><p>Through the intensive research spurred by the CMIP6 climate-sensitivity curveball, scientists have been able to turn a confounding challenge into a confidence builder, providing even greater certainty than they had before in both the abilities of the climate science community and in the computer models used. Moreover, the experience has helped unearth uncertainties remaining in the modeling process.</p><p>Experts conclude much of this uncertainty probably lies in the complexity of clouds. "We have been looking as a community at why the models with greater warming are doing what they are doing – and it's tied to cloud feedbacks in the southern mid-latitudes mostly," explains Schmidt.</p><p>In fact, <a href="https://advances.sciencemag.org/content/6/26/eaba1981" target="_blank">a new study</a> addressing the increased sensitivity was published in Science Advances stating, "Cloud feedbacks and cloud-aerosol interactions are the most likely contributors to the high values and increased range of ECS [sensitivity] in CMIP6."</p>
Understanding the Complexity of Clouds<p>It's long been known in climate modeling circles that cloud processes and interactions are a potential weak link for climate modeling. That reality has been brought front and center by the urgent challenges posed during this CMIP6 evaluation period, but the current evaluation of models also provides an opportunity for discovery and improvement.</p><p>Cloud complexity comes from the reality that clouds have a multitude of sizes, altitudes, and textures. Some clouds cool Earth by providing shade, reflecting sunlight back into space. Others act like a blanket, trapping heat and warming the world.</p><p>Given that about <a href="https://www.nasa.gov/vision/earth/lookingatearth/icesat_light.html" target="_blank">70% of the globe</a> is covered by clouds at any given time, it's no surprise that they play an integral role in regulating the climate. The challenge is to figure out which types of clouds will increase, which will decrease, and what the net effect will be on cooling or warming as the climate changes.</p><p><a href="https://www.nature.com/articles/s41561-019-0310-1" target="_blank">One study</a> last year reached an alarming conclusion: Left unchecked, the release of CO2 into the atmosphere may lead to a tipping point where shallow low clouds disappear – leading to runaway, catastrophic warming of nearly 15 degrees F. While scientists see that outcome as only a remote possibility, it drives home the urgent need to better understand clouds.</p><p>"We have a saying at NOAA: It isn't rocket science – it's much, much harder than that," quips Dr. Chris Fairall, ATOMIC's lead investigator. "One of the major problems for modeling is there is not clean separation of scales." The photo below is one that Fairall took from the NOAA P-3 aircraft.</p>
Investigating the Secrets of Clouds<p>To address the urgent question about the dynamics and role of clouds in a warming world, NOAA and European partners launched their ongoing research effort unprecedented in scale. The U.S. contribution, ATOMIC – short for Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign – is an international science mission that was featured recently on "<a href="https://www.cbsnews.com/video/study-aims-to-examine-links-between-climate-change-and-clouds/" target="_blank">CBS This Morning: Saturday</a>."</p>
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