Scientists and fishers team up to protect Bolivian river dolphin

Paul Van Damme and Fortuna Vargas Mejía met 28 years ago in Puerto Villarroel, a village in the Bolivian department of Cochabamba. Van Damme was a Belgian marine biologist who found in the lagoons of the Bolivian Amazon “the closest thing to a sea.” Vargas was a native of Cochabamba who had worked as a navigator for 12 years before becoming a fisherman, so he knew well the Amazonian rivers and lagoons that so fascinated the European scientist.

At that time — the 1990s — commercial fishing had just begun to boom in Puerto Villarroel, a municipality located on the banks of the Ichilo River in the Mamoré Basin, which includes three departments of the Bolivian Amazon. “In one day and a night I caught 1,200 kilograms [2645 pounds] [of fish], because there weren’t many of us,” recalled Vargas, who is now 70 years old and has not worked as a fisherman for 15 years.

Until then, the area and its forests had been well preserved and was home to a mainly Indigenous population. People from the Moxo and Yuqui Indigenous groups lived in communities along the banks of the river, living mainly off hunting, fishing and subsistence agriculture. Little by little, people from other parts of Bolivia started to move to the urban center of Puerto Villarroel and its outskirts, leading to it eventually becoming the main and largest commercial port connecting western and eastern Bolivia.

Van Damme was interested in studying how fish species and humans interacted, and Vargas Mejía took him and his team aboard his boat, allowing them to conduct research on the behavior and biological traits of the species living in the region. These investigations eventually led to the study of the bufeo, or river dolphin (Inia boliviensis), a species endemic to the Madera River Basin, the largest population of which is found in Bolivia.

As a predator of small- and medium-sized migratory fish, the river dolphin’s presence is viewed as an indicator of aquatic and riparian habitat health. Put another way: It is very sensitive to any changes in the ecosystem, and its absence or a fall in its numbers are therefore usually due to some kind of alteration in the environment.

Van Damme therefore started to collect data on the river dolphins, and Vargas Mejía helped him with this task.

It didn’t take long for the researchers to identify unsustainable commercial fishing as one of the threats facing the dolphins. However, far from viewing the fishers as a threat, Van Damme saw that as the friendship he had forged with Vargas Mejía had shown, the scientists teaming up with the fishers was the best strategy for the conservation of the animal. Van Damme was convinced that by participating in the scientific investigations, the fishers would come to understand the importance of protecting the river dolphin, and would therefore look after it — and that’s exactly what happened.

To learn more, a team of reporters recently traveled from Puerto Villarroel to Camiaco, inside the Gran Mojos de Beni Municipal Conservation Area, and sailed 450 kilometers (280 miles) along the river with the scientists and fishers in order to follow the most recent counting of the Bolivian river dolphin.

The iconic Bolivian river dolphin

In murky waters such as those of the Ichilo River, the dolphin was often seen shimmying to the rhythm of the waves and then disappearing, and it was a mystery as to where it would rear its head again. Sometimes, when the observation boat passed through warmer and clearer waters, small groups of 4-5 dolphins would appear in groups, showing no signs of fear of the nearby boat and seeming to play with each other. They have been seen using their tails to toss eels “like balls” at each other. Last year, nature photographer Alejandro de los Ríos captured a pair of dolphins with an anaconda in their mouths. It is not known if they were playing with it or about to devour it, but the image was featured in news outlets around the world including the New York Times. Fishers say that when the animal is in a group, there is always one that stands guard to warn the rest of the group of any danger, “like a communication whistle,” as Raúl Vásquez, a 31-year-old who has fished since he was a child, described it.

Until 2006, I. boliviensis was thought to be a subspecies of the Amazonian river dolphin, Inia geoffrensis, but through genetic and morphometric studies, it was identified as an independent species.

This differentiation, however, is still in the process of being recognized internationally. That is why, in the Bolivian Red Book of Vertebrates, it is considered a Vulnerable species, while for the International Union for Conservation of Nature it is listed as Endangered. Van Damme explained that the latter classification corresponds with I. geoffrensis, and efforts are now being made to seek a specific classification for the Bolivian species.

Far from the debate, experts in conservation, biology and ecology have reacted with astonishment to the findings about Bolivia’s only fully aquatic mammal. Details about these aquatic mammals include the fact that males prefer to swim in the middle channel of the river, whereas females tend to swim closer to the banks; they behave differently whether they are in dark or clear waters; the mothers and the whole group take care of the offspring; and not only do they not want their offspring to go near the fishing nets, but they seem to reprimand them when they do so. Such findings are “new and fascinating” information, according to Lila Sainz, wildlife officer for WWF-Bolivia.

According to the Action Plan for the Conservation of the Bolivian River Dolphin (2020-2025), the presence of the dolphin has been reported in nine protected areas across Bolivia. There is also a 10th area, not mentioned in the document, that scientists say is also home to important populations of the dolphin: the Gran Mojos Municipal Conservation Area.

Effective conservation efforts in these protected areas are, therefore, vital for the future of this species. Transmitters placed on individual Bolivian river dolphins by scientists, however, have revealed that the animals tend to migrate long distances, so they are not always found within the confines of protected areas.

“We have to take into account that I. boliviensis moves through rivers, but the other aquatic systems it uses, such as lagoons, meanders, and the surrounding habitat all are also important,” said Gabriel Tavera, a biologist and one of the researchers cited in the action plan. “Furthermore, a number of these protected areas flood with water during the rainy season, meaning the bufeo can also swim through flooded forests,” he added.

Between threats and protection

According to that action plan, the species faces three main threats: hunting and fishing, pollution and the degradation and loss of its habitat.

The first of these, the document claims, happens because the animal’s fat has traditionally been used to alleviate respiratory problems, but also, the animal can accidentally get caught in fishers’ nets and die by drowning; or because it is killed by fishers to avoid losing their nets. Its flesh has also been used by fishers as bait for fish such as tilefish, and it has also even been used on occasion by hunters to practice their shooting.

Despite this, Van Damme and Sainz maintain that the fishers’ close contact with the river dolphins means they can become allies in the fight to protect the species. In fact, though scientists can create conservation plans and strategies, “direct work with the individual citizens in contact with the resource is fundamental, since they are the ones who will decide whether to harvest all the fruits or leave some as seeds [for the future],” Sainz explained.

This was the vision behind the decision, 28 years ago, to include Puerto Villarroel’s fishers in the efforts to protect the species. At the time, Vargas Mejía and a small group of colleagues traveled along the specific stretch of river between the Ichilo and Mamoré rivers, recording the number of fish they caught, their weight, the temperature of the water and other details.

As fishing activities in Puerto Villarroel began to grow, more and more fishers became involved in the initiative because the information gathered allowed them to understand not only what was happening with the dolphin but also with their own activities. “If the quality of the aquatic ecosystems from which the fishermen catch their produce for sale changes, varies or degrades, then, of course, their economic situation is also going to deteriorate,” Sainz said. “One way of monitoring this is through the dolphins themselves, who are indicators of ecosystem health. If the dolphins are doing well, then the aquatic ecosystems are in good health and, therefore, the people who depend on the fish stocks will also be doing well,” she said.

“Paul awakened our interest in closely observing the species of fish that we used to catch. Previous to that, we didn’t really care about their life cycle. We went fishing because there was an abundance of fish, there was plenty. But as the number of fish started to diminish, we became more interested in the research and in working together [with the scientists]. That’s how we got interested in the river dolphin,” said Omar Ortuño, 51, who has worked as a fisher for three decades.

Since 2007, every four years, a team of scientists accompanied by local fishers have crossed 450 km of water, from Puerto Villarroel to Camiaco, in the Gran Mojos Municipal Conservation Area, to find out more about the population trends of the Bolivian river dolphin. For five days or more, a fishing boat becomes an operations center where, at a speed of 10 km (6 mi) per hour, six experts — three at the bow and three at the stern — observe, record and measure distances, temperature and wind fluctuation, among other things.

Strategies for studying the Bolivian river dolphin

In the most recent expedition carried out in September, fisherman Raúl Vásquez was selected as one of the observers for his experience and sighting skills, and 320 individual dolphins were counted, 180 fewer than in 2018. The possible causes for this fall in numbers are still being studied.

“On this trip we realized that the bufeo is found in few habitats. It only uses the river to move from one point to another,” Van Damme said. Most important of all, he added, is that the dolphin needs places that are tranquil and in which it can shelter away from the river’s current. Many of these calm spots are also chosen by fishers for casting their nets when there are no schools of fish arriving, meaning the dolphins and the fishers are competing for the same resource.

To complement these dolphin-counting expeditions, a mobile app called BUFEO was developed in 2021, which works without an internet connection and allows the fishermen to register the presence of the animals. The app also allows the user to send a variety of information to a database, such as the exact location of the dolphin sighting, the date, the weather conditions and whether it might be male, female or a calf.

Nine fishermen are currently using the app, although it wasn’t easy for all of them to adapt to using it. “For me it was a little complicated to drive [the boat while using the app], because I had to start when the river’s water level was low and you have to be careful of the tree logs. It’s the same as driving [a car] on the road. If we are on our phone, we can have an accident,” said Jhonny Mendoza, 31, a fisherman and Vargas Mejía’s son-in-law.

Finally, the scientists also installed a weather station in Puerto Villarroel, which includes a permanent thermometer to measure the water temperature. This was done with the aim of learning about changes to the river’s current that may affect the fish populations, as well as to find out whether the paiche, an introduced species of fish that is very sensitive to low temperatures, can reach this area, which is considered cold, and thereby compete with the Bolivian river dolphin for food.

Although Raúl Vásquez, the fisher who accompanied the team of scientists on their latest expedition, met Van Damme when he was a child, that was the first time in his life that he had participated in the observation of the Bolivian river dolphin. “I learned a lot,” he said, “because I saw that we have to be more careful, at least with the bufeo, [because it’s] a marvelous creature.”

For Vásquez and his wife, Ana Estefanía Carreño, who also lives off fishing, seeing scientific work up close has been an enormous learning opportunity. “I already knew about the bufeo, but now I’ve learned how to look after it. They understand this, they are intelligent and I’d like to teach my children how to do it, too,” she said.

The couple recalled how on one occasion on the Ibare River, two of the dolphins got caught up in their fishing nets. One managed to free itself, but the other was stuck. In the past, Raúl said, he might have chosen to kill it, but instead they chose to free it. “I touched it and it was beautiful. I thought that it would be slippery, but it wasn’t. My husband cut the mesh with a knife and we let it go.” At that point, the woman thought the dolphin’s life was well worth weaving another net.

The next challenges

The next step is to enlist the help of the fishers who live in Camiaco, in the department of Beni. This represents a challenge, given that Gran Mojos — the municipal conservation area that Camiaco is a part of — does not have a list of regulations that establishes what is and isn’t allowed within its borders, and there is also a lack of economic resources to control commercial fishing, the conservation area’s director, Richard Barrios, said.

Furthermore, just as there are fishers in Puerto Villarroel and Camiaco who carry out their fishing activities legally — because they have the correct permits from their governments — there are also others who do not comply with the law, according to fishers from both regions who do things legally. The same fishers have also claimed that those flouting the rules also catch fish during the closed season with larger nets than those established in the Sustainable Fishing and Aquaculture Law.

“Fishing can be balanced with conservation, but it requires intervention on the part of the public authorities, as well as a lot of participation by local people,” Van Damme said. “That’s what we’re working on, trying to get fishermen to act as protectors of their own river. Now many of them are starting to see that the Bolivian river dolphin can be an ally in attracting tourism [to the area],” he added.

Meanwhile, the fishing records kept by the fishers of Puerto Villarroel for the last 28 years has allowed researchers to demonstrate in a study that the construction of the Jirau and San Antonio dams in Brazil has had a much greater “visible and measurable” impact on fish and dolphins than the fishers have. The construction of these dams interrupted the migration of some fish species that the Bolivian river dolphin relies on as sources of food, the study explained.

“Actively involving them in the study has allowed fishermen to be more conscious of the role that the Bolivian river dolphin plays in maintaining an ecological balance in the Ichilo River [which] sustains their livelihoods,” Van Damme said.

This whole process has been part of a three-decades-long effort. Today, the fishers who travel up and down the river in search of the Bolivian river dolphin are the sons and sons-in-law of the fishers who first started working with Van Damme all those years ago.

Banner image: Image courtesy of Carmelo Calderón.

This story was reported by Mongabay’s Latam team and first published here on our Latam site on Nov. 29, 2022.

Related audio from Mongabay’s podcast: Two expert guests discuss the effectiveness of combining traditional Indigenous ecological knowledge and Western science for conservation and restoration initiatives, listen here:

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