The list of fish species in Brazil has just been updated. An article published this Monday (16) in the specialized scientific journal Zoological Journal of the Linnean Society with the description of two new species of fish from the Brazilian Amazon brings data on the biology, morphology and distribution area of the animals. But, depending on the accelerated pace of Amazon deforestation, the new members may have their days numbered.
This is because the species known as Poecilocharax callipterus and Poecilocharax rhizophiluswere found by a team of Brazilian scientists in just two locations on the Juma River, a tributary of the Madeira River, in the state of Amazonas, between the municipalities of Apuí (455 km from Manaus) and Novo Arapuanã (227 km from the capital of Amazonas). ).
Because they are tiny animals—the largest of them, P. callipterusis 3 cm long, and the P. rhizophilusconsidered a dwarf species, is 2 cm long — the environmental impact caused by forest fires and the transformation of the Amazon rainforest into pasture can put the little fish at risk of extinction.
The research, led by Brazilian scientists Willian Ohara, from the Federal University of Rondônia, Murilo Pastana, a postdoctoral fellow at the Smithsonian Museum of Natural History, in Washington, DC (USA) and Priscila Camelier, a professor at the Federal University of Bahia, in Salvador, is a great contribution to the knowledge of the world’s tropical fish fauna.
It all started in 2015, with an expedition between the team from the Museum of Zoology of the University of São Paulo, where Pastana was doing his doctoral research, and the Federal University of Rondônia, with the aim of mapping areas not yet explored in the Madeira River, the second largest river in the Amazon basin and possessing the greatest biodiversity of fish ever known in the world.
On the first trip, the scientists found, photographed and collected the two animals in two different locations. The biggest species, P. callipterus, characterized by a unique coloration that differentiates it from the others for the genus, was found in an area of the Canada stream, in the Juma River. The animal lives in dark waters, with a high concentration of decaying leaves — hence the black color.
Already P. rhizophilus was collected in two places, in the Paredão waterfall, also in the Juma River, but living close to trees with aquatic roots (igarapés), hence its name (“rizo”, from the Greek, root, and “philos”, to like). The animal is so small that it can even hide in the holes between the roots, explains Ohara.
According to the ichthyologist (fish specialist), it is likely that there are still other species to be discovered in the region, since for these animals, falls, waterfalls and other geographic barriers can lead to speciation. “Probably the presence of these species there is related to this waterfall, and there may be others yet to be discovered,” he said.
However, the speed with which scientists are able to study and describe a new species is always infinitely lower than the speed with which deforestation advances, says Ohara. “The south of Amazonas, north of Mato Grosso and Rondônia have always been part of the so-called arc of deforestation, but this region of Apuí, unfortunately, in recent years has seen deforestation increase mainly through speculation [de terra] and because of the outflow of beef,” he said.
This could be seen even in the short interval of about a year until the second expedition, in 2016, when researchers searched for, but found no more individuals of the species. P. callipterus in other locations along the Juma River, only in the delimited area of approximately 4 km² where it was first seen.
According to the authors, the strong environmental impact in the region at the time and, now, more intensified due to the recent fires in the region, made the classification presented in the article from “critically threatened” to P. callipterusand “highly endangered”, for P. rhizophilus.
Another problem the two little fish face is aquarium hobbyism. Because they are considered ornamental, due to their striking coloring and are highly sought after by South American darters fish collectors, it is likely that the commercialization of the animals puts them at even greater risk of extinction.
For Pastana, the country lacks a culture of valuing the scientific and biological collection, as is observed in other parts of the world. “These are the first two species of the group described in 57 years. Losing any one of them due to deforestation would be like losing a work of art in a museum, it is part of a collection that never comes back”, he says.
One of the ways to increase the popularity of surveys like this is to create a space that attracts attention in the digital environment, where every human interaction is today.
Because of this, Pastana and other colleagues from the USP Museum of Zoology created the Instagram page “Peixe ao Quadrado” (@peixe.aoquadrado), where they publicize new species of fish discovered in pixelated format. “It’s a form that resembles a video game, and ends up attracting the attention of younger people, who like this geek universe,” he said, saying he hoped that this could help to create a culture of valuing biodiversity in the country.
