Groundbreaking research seeks to protect Amazonian fish species
The pirarucu (Arapaima gigas) and the filhote (Brachyplatystoma filamentosum) are two Amazonian fish species that, in addition to sharing their native biome, have other characteristics in common: high demand in gastronomy and difficulty reproducing in fish-farming environments.
These characteristics led to their selection as the first species to have their DNA decoded in a pioneering study conducted by the Federal University of Pará (UFPA).
According to researcher Sidney Santos, who led the team at the Human and Medical Genetics Laboratory of the Institute of Biological Sciences, the study was motivated by the need to contain the impacts of the advance of predatory exploitation of these species, driven by increased demand.
The central idea is that, if you can acquire enough knowledge in a balanced and targeted way to produce these fish as sustainably as possible, you can reduce the demand on nature,” he explains.
DNA
The most complete way to seek this knowledge is by deciphering the DNA (deoxyribonucleic acid) obtained from biological samples of various individuals of the species. This molecule, composed of four types of nucleotides - adenine (A), thymine (T), cytosine (C), and guanine (G) - holds precise information about health, physical traits, and ancestry, among other characteristics.
In the study of the pirarucu and its offspring, scientists collected samples from more than 100 fish so that their DNA could be read by a genetic sequencer capable of determining the order of nucleotides. Each different sequence provides information about a living being, which together form the genome of the species - a kind of complete manual for the group.
“This can apply to any animal you can imagine, or any plant. The model is always the same. If you can, in a sustainable way, obtain complete information about the genome of these animals, you can work with them, including reproducing them,” Santos says.
Traceability
The protection of species goes beyond reducing the removal of naturally reproduced fish from the environment. Through knowledge of a species’ genome, it is also possible to determine the precise origin of an individual animal.
According to Igor Hamoy, a director at the Socio-Environmental and Water Resources Institute of the Federal Rural University of the Amazon, who participated in the study, the genome enables genetic traceability in addition to physiological insights.
“With the history contained in the pirarucu genome, for example, I can determine whether a pirarucu being sold in Boston (USA) originated in the Amazon,” Hamoy says.
He also emphasizes that all the information generated by the study is recorded in a public genetic database, enabling further research on the species.
“I can determine exactly which species it is and eliminate doubts about whether the scientific or common name used by a community truly refers to the fish that Amazonian community has been eating and working with for a long time,” he explains.
Advances
It was based on this information that researchers were able to advance in addressing the main obstacles related to pirarucu and juvenile fish farming: sex hormone induction, the development of adequate nutrition for artificial environments, and traceability to prevent Amazonian species from being illegally traded.
According to Rita Mesquita, National Secretary of Biodiversity, Forests, and Animal Rights at the Ministry of the Environment and Climate Change, these scientific advances are guiding principles in the implementation of public conservation policies in Brazil.
“Genetic research contributes to expanding our knowledge of Brazilian biodiversity and helps us better understand what has already been done and what still needs to be done,” she stated.
According to the secretary, planning through 2030, as set out in the National Strategy and Action Plan for Biodiversity (Epanb), was developed based on what science indicates is necessary to reduce biodiversity loss and regenerate Brazilian biomes.
Some public policies depend even more on genomes deciphered by scientists, such as the development of lists of invasive exotic species and the National List of Endangered Species. Another example cited by the secretary is the National Plan for the Recovery of Native Vegetation (Planaveg), launched by the Brazilian government in 2024.
“In rewilding processes, where fauna has disappeared, or in vegetation restoration, this library of genetic information allows us to access the knowledge needed to return species to their proper places,” Mesquita explains.
Challenges
According to researcher Sidney Santos, expanding studies to decipher the genomes of species is a type of knowledge likely to advance both in Brazil and worldwide, mainly due to the decreasing cost of the necessary resources.
“The human genome, which was the first, took 10 years to complete and cost between USD 2.5 and 3 billion. Since then, machine power has increased. Today, with the MGI - the DNA sequencer we use - we can process 48 human genomes in three hours at a cost of USD 1,500 to 2,000, which I hope will decrease further,” Santos says.
According to the researcher, in addition to UFPA’s equipment being the only genetic sequencer in the public sector in the Amazon, there is also the so-called “Amazon cost,” caused by logistical and operational difficulties.
“The cost is lower today, but it’s still not affordable for every researcher or university. That’s why the technology park at UFPA’s Human and Medical Genetics Laboratory is able to handle all of this,” he added.
For Rita Mesquita, the work to ensure that species are not lost is a challenge as great as the country’s biodiversity - the largest in the world.
“What the Ministry [of the Environment] does in this regard is continue working with science to improve our information on priority areas and to keep seeking the protection of territories for species - especially the most threatened - so that they receive proper protection and are prevented from disappearing,” Mesquita emphasizes.
“The role of science is fundamental in generating knowledge that guides human interaction with species in any biome according to sustainability parameters,” the secretary points out.
“This applies to animals and plants. If we have ways to manage them sustainably - ways to recover, restore, and return species - we can establish a relationship in which species are managed based on sustainable, low-impact principles, with populations maintained in protected areas,” Mesquita concludes.
