From Colombia to Ecuador, Amazonian Fish Face Many Threats

It is six o'clock in the morning on the banks of the Putumayo River in Puerto Leguízamo, an Amazonian municipality in Colombia. Yeison Rodríguez, the legal representative of the local Fishermen's Association, waits patiently for the arrival of his colleagues, who have been fishing all night. He arrived at 5:30 a.m., as he does every day, but today he has not received good news. His colleagues couldn't capture a single fish.

The scene is becoming more and more frequent. At this time of year (late May), he says, the river should be totally overflowing... But it's not happening yet. "Catfish fishing and, in general, in this area, depends a lot on the level of the river. If by July the Putumayo has not reached its top, there is a great probability that this year there will be no high levels either," he explains. It has been three years since the fishermen's most awaited catch hasn't arrived. 

Leguízamo is a territory full of streams, creeks, lagoons, flood zones, and medium and large rivers. The life of the locals takes place among these bodies of water: They are their main transportation system, their source of food and their economic sustenance. They are also key to the lifecycle of fish, acting as breeding or feeding grounds and the place where interactions —which until a few years ago were coordinated with great precision — between terrestrial and aquatic ecosystems take place.

For those who live there, fishing has been part of life. It is the sustenance of their diet, which includes at least 104 species of fish. When there is no work, when a pandemic strikes, when they are hungry, their best ally is the river. But now they are worried that the dynamics are changing, that the big fish are no longer coming up, that they are not abundant. They are worried that nowadays, on any market day, around 10 a.m., the area of the square where they sell their catch is completely empty.

Getting from Puerto Asís, another Colombian Amazon municipality, to Puerto Leguízamo takes almost eight hours by speedboat. The Putumayo River, the 10th largest tributary of the Amazon basin, is the only highway for the trip. People, food, errands, money, cows, inputs and products of "monoculture," as they call everything that has to do, really, with illicit crops, move along it.

The river is also what defines how far Colombia reaches and where Ecuador begins, or, later, Colombia and Peru. Mainly on paper maps, because on a day-to-day basis, the flow between the two shores is as common as crossing from one sidewalk to the other. Rather than separating two countries, what the Putumayo River really does is connect frontiers.

Underwater, one of nature's most impressive journeys takes place: the migration of the great Amazonian catfish, which travels almost 12,000 kilometers, passing through at least five countries in the Amazon basin, without stopping to stamp their passports.

"The history of migratory fish," says César Bonilla, a biologist at the Amazonian Institute for Scientific Research, SINCHI, in Puerto Leguízamo, "is an incomplete story. By having such a long migration, there are parts of the lifecycle of these species that occur in other areas, territories, communities or countries, and that we don't know about."

"We only get a small part of it," he adds. 

Species such as the golden catfish (Brachyplatystoma rousseauxii), which holds the record for the longest freshwater migration in the world, has its breeding grounds in the headwaters of the Andes and the Amazon. Between the Caquetá and Putumayo rivers in Colombia, also called Japurá and Iça, respectively, in Brazil; the Napo in Ecuador; the Marañón in Peru and Ecuador; the Ucayali in Peru; and the Madeira (which joins the Mamoré and Beni in Bolivia, and the Madre de Dios in Bolivia and Peru). From there, the small larvae travel with the current across the width of the subcontinent, until they reach Brazil, where the Amazon River flows into the Atlantic Ocean. But that's only half the journey.

"In this estuary, which is like their nursery, they live for at least two years," explains Edwin Agudelo, leader of the Aquatic Ecosystems Research Group of the SINCHI Institute, from La Pedrera, in Caquetá. One of the most important catfish fishing points in Colombia and the region. In the estuary they reach size and maturity to travel back upstream to the headwaters, which are also the spawning grounds. "Countercurrent migrations can last another two or three years, and are influenced by the river's flood pulse," he adds. Heavy rainfall, which increases the flow, stimulates them to start the climb. When they arrive, a new cycle begins.

And although there are still many questions to be answered, such as what are the exact spawning sites, how do catfish orient themselves to return to the areas where they were born or why do they make such long migrations to reproduce, there are other certainties... Many factors, of human origin, are leading these populations to a possible collapse.

"In that fraction of history that Colombia has reviewed, and that the Sinchi Institute has been investigating for decades, it has become evident that, since 1994, after reaching their peak, the fisheries of the large catfish, which are also indicators of their populations, have collapsed," says biologist Bonilla. A similar situation exists throughout the region. Although each zone has different stories, there are versions that are shared throughout the basin.

These animals, which depend on migration between the Andes and the Atlantic to survive, are increasingly facing a difficult combination: the ecosystems they inhabit are already suffering the consequences of loss of river connectivity, deforestation, pollution, mining, hydrocarbon extraction, climate change and overfishing. When they make it through one zone, they move on to the next, carrying the remnants of these threats in their bodies, and facing some new ones.

Studying and protecting this migration is no easy task. Especially in such an extensive and complex system, which is crossed by different countries, authorities, communities and governments.

Communities affected by fish absence

Linda Bucheli has been fishing since she was a child in the rivers of her native Amazonian province of Orellana, Ecuador. More than 30 years ago, she used to accompany her father on fishing trips on the Payamino, Coca and Napo rivers. At that time, she says, catfish commonly known as pintadillo and lechero were abundant. Now, she says, "it's like finding a needle in a haystack”. They are not easy to catch.

In the Ecuadorian Amazon, fish are the main source of food for nearly 957,000 people. As Ricardo Burgos, a researcher at the Universidad Estatal Amazónica, says, each inhabitant of the banks of the Amazonian tributaries consumes about 18 kilograms of fish per year, while the average Ecuadorian consumes 6 kilograms. Now, that source of protein is harder to come by. "While we used to catch 100 pounds of fish in two or three days... now it takes us six or seven days to bring in 40 or 50 pounds," says Bucheli, who is also the president of the Napo River Fishermen's Association.

The same happens on the other side of the river, in Colombian territory, upstream, in the municipality of Orito, also known as the "Oil Capital of Putumayo." Fernando and Fredy, fishermen from the area, remember how yellow catfish and pintadillo could be easily caught under the Orito River bridge. "Now you see one around there every couple of years."

This is a global phenomenon. The first report on the state of the world's migratory freshwater fish, by the World Fish Migration Foundation and the Zoological Society of London, found that their populations have declined by 76% in the last 50 years. The drop has been most dramatic in Latin America, where populations declined by 84%.

"Thirty years ago, the golden catfish accounted for 62% of the catch in the lower Caquetá," says Carlos Rodríguez, director of the Tropenbos Foundation, which for years has been recording, together with fishermen, the catch and populations of catfish in the Chorro de Araracuara. His archive, full of books and data, shows that 50 tons of fish were caught in 1984 from that point alone. During the fishing boom, between 1995 and 1998, huge quantities of "tabludos" catfish, the locals' word for large fish, were being taken. "At that time we warned that, if conditions continued like this, the fishery was going to collapse... And it fell faster than I imagined," he says.

The changes in catches, the technification of fishing, the installation of refrigerated rooms, the cargo flights that delivered the fish to the interior of the country and the fall of the populations transformed many of the dynamics of the region. "As the catches of large catfish, such as dorado, for example, decreased, other species of medium-sized catfish, with shorter migrations, gained ground in sales," explains ichthyologist Edwin Agudelo. Then, smaller catfish were used and, later on, the migratory scale catfish, such as bocachico or shad, which used to be fished not for sale, but for self-consumption. "Today people eat species that they did not eat before, because the supply of the resource has changed," adds biologist Bonilla, also from SINCHI.

"This has greatly affected the lives and economy of those of us who depend on them," says Yeison Rodríguez, from Puerto Leguízamo.

"Now fish is scarce and expensive. And we would like to find out what is going on. If there was overfishing, if there are very small catches, if they are not spawning or if they are not being allowed to come up from downriver." 

Rules and regulations change from country to country. Linda Bucheli and her colleagues from the Napo River Fishermen's Association have self-imposed "no catch months" and minimum catch sizes to help fish recovery, but that is not an obligation in Ecuador's Amazon. Ecuador, for example, has no regulations regarding fishing on its rivers. Nor is there any official data on how much is extracted from its Amazon region, or about the current state of these species.

Mining and deforestation: what happens on land affects water

The mining boom has spread throughout the Amazon. Several bonanzas, driven by the rising price of gold, have boosted this activity throughout the region. According to the Amazonian Network of Geo-referenced Socio-environmental Information (RAISG) and information compiled by the FCDS, 51 protected natural areas and 29 indigenous peoples have been affected by illegal mining in the Brazilian Amazon. In the Colombian Amazon, six protected areas and 16 indigenous territories are affected.

On the Putumayo River, in the Colombian Amazon, illegal mining is just another activity among the inhabitants, like cattle ranching or coca cultivation. People buy the land to "mine" or to lease it for others to mine. There are specialized geographers who, with a map, show landowners the areas of their farm where they can extract gold. Lorena, an inhabitant of the region whose name has been changed to protect her identity, said that when she bought her land, a geographer pointed out the area with gold. "With what I have in this triangle, I have enough to live on for the rest of my life," she said. With illegal mining she built her house and gave her children an education.

Although in some areas of Caquetá, Guainía and Putumayo alluvial gold is mined with rafts, dredges and backhoes that remove sediments from the river, in others it is done in a more "artisanal" way. "Mining here in Putumayo is mostly illegal. The veins can be found just two meters off the ground and, with the help of a motor pump, the families remove the mud for several days and then make a gutter through which the gold comes down," explains Lorena. According to her, artisanal mining does not use mercury, as in large-scale mining. But the soil is removed and channels are opened during the process. The streams in which they mine are stained with the reddish color of the earth.

In the first half of 2015, during one of the region's mining booms, 65 dredges were documented in the Caquetá River, 25 in the Putumayo River and eight in the Cotuhé River. According to figures from the United Nations Office on Drugs and Crime, 30% of the Colombian territory affected by alluvial gold mining coincides with the presence of illicit crops. In Caquetá and Putumayo, this percentage rises to 80%. "The mainstay of Putumayo is mining and coca. And currently, with the coca crisis, mining is what is providing sustenance," says an inhabitant of the area.

But illegal exploitation and lack of control also have their impacts. The Coca and Payamino rivers, as well as the headwaters of the Napo River in Ecuador, as well as other tributaries in the region, are essential for the reproduction of species such as the golden catfish. And, as in the rest of the Amazon, mining in this area has grown rapidly in the last seven years. In Napo province alone, the area of mining activity increased by 300% since 2015, according to data from the MapBiomas project. In the area of Yutzupino, in the south of the province, it increased 80% in one year.

The Ecuadorian Ministry of Environment, Water and Ecological Transition (MAATE)  reveals that 94 illegal mining sites have been identified in this Amazonian province. On the other hand, this same Ministry has granted environmental permits to 583 metallic and non-metallic mining concessions throughout the Ecuadorian Amazon to operate legally.

The growth of this activity worries researcher Jenna Webb, who has so far conducted the most comprehensive studies on the presence of mercury in fish and Amazonian communities in Ecuador. Although they were published between 2004 and 2016, another similar study has not been conducted since. And at that time, the results were already worrying.

Webb obtained hair and urine samples from members of three Amazonian communities in Napo. The findings of her study showed that women who obtained water from streams or the river had twice as high concentrations of mercury as those who had access to groundwater or rainwater. In the case of men, urine samples showed organic mercury, which is not the mercury that enters through fish. What was found was that those who had worked on the oil spill cleanups had a higher concentration than the other men in the community.

They also analyzed 468 fish samples, where catfish recorded the highest concentrations. The idea is not to cause panic, says the researcher, but to make people understand that these fish that eat others and are part of our diet bioaccumulate mercury.

Another more recent report, by Ricardo Burgos, reveals that 97% of catfish analyzed in the Ecuadorian Amazon exceeded on average up to five times the concentration of mercury in fish recommended by the World Health Organization (WHO) for human consumption. More bioaccumulation was observed in the lower reaches of the watersheds.

Similar studies have been done in Colombia. One of these, which took samples from residents of Puerto Nariño, found mercury concentrations on average 18 and 19 times what the WHO establishes, whose limit is a concentration of one part per million.

"Mercury is a risk to human health, but it can also greatly affect the lifecycle of species, which begin to accumulate these toxic metals and become ill, mutations occur, they lose viability of their eggs and have an inadequate physiological development," adds biologist Edwin Agudelo. As the mobility ranges of migratory fish are wider, in areas where there is no direct mining, the people who consume them can also be affected. "All mercury pathways lead to humans," summarizes researcher Víctor Moreno of the Foundation for Conservation and Sustainable Development (FCDS).

Even if mercury was not used in mining activities, it is also found naturally in soils. Deforestation for land grabbing, mining or hydrocarbon projects removes sediments with chemical elements that, if it wasn't for deforestation, "were neutralized and were not susceptible to becoming organic and being incorporated into the trophic network," says Moreno.

Data from the Ecociencia Foundation show that, in just over five years, 1,660 hectares have been deforested by gold mining in the Ecuadorian Amazon. In Colombia, although deforestation decreased for the first time in ten years, 123,517 hectares were cut down in 2022 alone.

The problem, experts say, is that when vegetation cover is removed, there is no way to retain water in the face of heavy rainfall. The soil dissolves in the rivers. "Sediment saturation is so high that it can obstruct fish gills, generating mortality," explains Silvia López-Casas, PhD in biology and expert in freshwater fish and the Amazon biome. "It's as if we have to breathe in a dusty environment. Especially when we are making an enormous effort during the migratory exercise," she adds.

Hydroelectric plants, a new threat

Globally, only 37% of rivers longer than 1,000 kilometers flow freely throughout their entire length. Dams, increasingly used to produce electricity in the region, interrupt fish migrations and change flood pulses and water cycles.

According to WWF's Amazonia Viva report, in the Amazon biome "there are around 250 proposed dam projects, which could severely alter the hydrology of the entire biome and have catastrophic impacts on migratory fish species". Ecuador alone, which has the smallest portion of the Amazon, has 18% of the active hydroelectric dams. Most of these projects with environmental licenses are located in Napo.

The impacts are already evident. Coca Codo Sinclair, the largest dam in this country, for example, has been associated with a process of erosion that eventually led to the disappearance of the San Rafael waterfall. Members of the Fishermen's Association, such as Linda Bucheli, are some of the communities that have felt the impact of the installation of this project. They relate the reduction in quantity and size of their fish to the impacts of the hydroelectric plant, which are coupled with the aftermath of mining and oil in this area.  Daniel Escobar Camacho, a scientist at the Universidad San Francisco de Quito, explains that the hydroelectric structures act as obstacles along the fish migratory route and, in doing so, separate their populations.

Ricardo Burgos-Morán, of the Universidad Estatal Amazónica, says that hydroelectric projects could help generate more data on these fish, but researchers or universities are not included in their environmental impact studies. As a result, there are almost no complete analyses of the status of the fish in the area.

The specialist fears that with the expansion of these projects, they will become even more of a threat. The Paute-Molino hydroelectric plant, for example, is associated with the disappearance of a catfish of the genus Astroblepus that inhabited Cuenca, which is the westernmost city in the Amazon basin. The power plant, which has a capacity of 1,100 megawatts and is the second largest in the country, is located on the Paute River, 115 kilometers from Cuenca. Since its installation 39 years ago, this species has not been found again.

How to reverse the silent disappearance of migratory freshwater fish? All the people interviewed for this report agree on one thing: concerted and shared management is required to ensure the sustainability of species and ecosystems. "If catfish migrate for thousands of kilometers, the responsibility extends for thousands of kilometers and for the actors that are over these thousands of kilometers," assures Carlos Rodriguez of Tropenbos. "That is the challenge. Re-establishing institutional presence, promoting the organizational capacity of grassroots communities and promoting coordinated actions."  

So far there are no international regulations or agreements to conserve large migratory catfish. Nor is there a program dedicated to monitoring their fishing. There are no integrated statistics on fishing in the different regions along the basin and there are no Amazonian fish in the species conservation treaties, even though they have the longest freshwater migrations on the planet.

On June 12, the Government of Brazil submitted to the UN Environment Program's Convention on Migratory Species the proposal to include the golden catfish in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS).

"It is crucial to establish an integrated commitment among the countries where these species coexist to plan and develop initiatives, actions and strategies to conserve the species, manage and make sustainable use of the fishery resources, in order to achieve environmental, social and economic sustainability in those countries," reads the proposal document.

The meeting of the parties will take place in Uzbekistan between November 23 and 28 of this year (2023). To date, all Amazon countries, with the exception of Colombia and Venezuela, are signatories to CMS. Meanwhile, underwater, migratory fish are silently resisting the threats.

This story was produced with support from the Earth Journalism Network. It was first published in El Espectador and Youtopia on September 4, 2023. It has been lightly edited for length and clarity.

Banner image: An illustration of fish / Credit: Eder Rodríguez for El Espectador.