The Arapaima gigas, a giant fish species, has invaded the Amazon region of Bolivia, reaching weights of up to 200 kg. This poses a threat to local wildlife, yet it is also a valuable resource for fishermen.
No one knows exactly when the Arapaima gigas first arrived in Bolivia. Many experts believe that they escaped from fish farms in Peru, where they are native. From there, they spread into the rivers of Bolivia, as reported by BBC on December 28.
Arapaima gigas is one of the largest freshwater fish species in the world. (Photo: Sergio Ricardo de Oliveira).
This is one of the largest freshwater fish species in the world, capable of reaching lengths of up to 4 meters and weighing over 200 kg. It is estimated that each year, Arapaima gigas invades 40 km deeper into the rivers of the Amazon. Their size and voracious appetite make them a serious threat to native fish, according to Federico Moreno, director of the Aquatic Resource Research Center at Beni Autonomous University.
“They are territorial fish. They dominate a water area and scare native species away. This is one of the serious issues. Other species flee from predators and move to other waters, which are much farther away and very difficult to access,” Moreno stated.
Arapaima gigas is an opportunistic feeder, according to biologist Fernando Carvajal, an expert on this species. “In their early years, they grow at a rate of 10 kg per year. This means they eat a lot of fish,” he said.
Unlike other predatory fish such as piranhas, Arapaima gigas has small, not very sharp teeth. However, this does not prevent them from eating piranhas and many other fish, along with plants, mollusks, and birds. Arapaima gigas consumes everything like a giant vacuum cleaner, and they instill fear in any fish that might try to prey on them.
Carvajal noted that there is currently no solid data on the impact of Arapaima gigas, but fishermen report that the populations of some native species are declining. “In the next one or two decades, Arapaima gigas will spread to all potential areas where this species can live. We know that in the world, most cases of invasion are harmful to nature. Invasive species are considered the second-largest cause of biodiversity loss, after habitat destruction,” he warned.
However, for local fishermen, the presence of Arapaima gigas also brings significant benefits. Fisherman Guillermo Otta Parum stated that he initially felt concerned but quickly recognized their potential. “When I brought the first fish home, I would give customers small pieces to try and experience the flavor,” Parum said. Currently, they have become a popular dish throughout Bolivia.
The challenge for fishermen is finding Arapaima gigas in the vast Amazon region. This species has a lung-like organ and must frequently surface to breathe air, so they prefer calm waters. They thrive in lakes and lagoons but will migrate if they sense danger.
Scientists like Moreno hope that fishing will help control the population of Arapaima gigas. “Keep hunting them, keep fishing. This could maintain a balance among different species,” he said.
