Colombia Is Creating a DNA Library to Protect Fish in the Magdalena River
In an effort to enrich a global scientific project that seeks to establish DNA libraries of marine and freshwater fish, researchers from the University of Antioquia (UDEA) and Empresas Publicas de Medellin (EPM) have spent two decades collecting genetic material from the species found in the Magdalena River basin, Colombia’s most important river basin.
The research team has reported data from 1,270 specimens, which make up a molecular catalog, meaning an organized record that identifies the DNA fingerprint of each individual. This inventory functions as a reference genetic library, whose value lies in allowing scientists to accurately identify the species in the basin.
For more than 20 years, the group has accompanied wildlife monitoring efforts that EPM must carry out as part of environmental licensing requirements at its various reservoirs, especially those in the northern and northeastern subregions of Antioquia, where Porce II and Porce III stand out, and more recently Riogrande, explained Professor Luz Fernanda Jimenez Segura, leader of the team and coordinator of the Ichthyology Group (GIUA), attached to the Biology Institute of the Faculty of Exact and Natural Sciences, quoted in a UDEA statement.
“We Must Know Well in Order to Protect Well”
“Achieving this distinction [of fish species] is key to understanding their life habits, reproductive strategies, and survival challenges. Ultimately, this knowledge is the fundamental input for designing better conservation strategies. After all, we must first know well in order to protect well,” said Andres Felipe Galeano Moreno, EPM environmental professional, quoted in the same publication.
This repository stores information on the deoxyribonucleic acid of the species, based on a technique called DNA barcoding, and classifies it in an organized manner so that interested parties can consult the material. To do so, they must request authorization through the email grupoictiofauna@udea.edu.co.
To build this inventory, the team carried out a historical search of “type localities,” meaning the exact points where past explorers first described each species. Initially, the researchers prepared a list of the sites visited by German-American ichthyologist Carl Eigenmann in 1912 and traveled through rivers such as the Magdalena and Cauca, as well as others outside that basin, such as the Catatumbo.
One of the greatest challenges of that exploration in recent years was the difficulty of accessing some locations, both because of physical conditions—rugged terrain and jungles—and security issues resulting from the armed conflict. However, for the scientists it was necessary to do so because they were aware that there was a gap in ichthyological information for many areas of that interconnected macro-basin. But after the peace agreement between the National Government and the FARC, beginning in 2017, they were able to start accessing a large part of those territories.
In Colombia, in addition to UDEA, the Humboldt Institute, the Amazonian Institute of Scientific Research, and universities such as the National University, the University of Valle, the University of the Andes, among others, and under the same circumstances, have carried out similar projects in regions such as the Amazon, the Orinoco, the Pacific, or the mountain basins that supply water to reservoirs in Antioquia.
During their expeditions, the UDEA and EPM scientists “not only collected physical specimens, but also took tissue samples from them in order to extract DNA and sequence some genes,” added Professor Jimenez Segura.
Virtual Library of “DNA Barcodes”
In the Ichthyology Group laboratory, researchers standardized the use of genetic markers, which are DNA fragments that function as a “fingerprint” to identify species. This allows them to differentiate organisms that are morphologically very similar, identify larvae whose appearance changes during development, and even recognize species based on environmental DNA (eDNA), meaning the genetic material that organisms naturally release into water.
Combined with new-generation massive sequencing techniques and metabarcoding analyses, these markers make it possible to simultaneously detect dozens or hundreds of species present in a single water sample, without the need to capture organisms. This approach represents an innovative tool for biodiversity monitoring, as it allows the rapid, accurate, and non-invasive evaluation of the composition of fish communities.
The genetic sequences obtained were integrated with high-resolution photographs taken through the Photafish system, specially designed to record the physical characteristics of fish. Subsequently, all the information was stored on the CavFish Colombia platform, where the combination of DNA and images made it possible to confirm the exact identity of each fish.
This process was the foundation for creating a virtual library of “DNA barcodes,” which brings together information from 1,270 individuals belonging to 183 species, 90 genera, and 36 families of fish from the Magdalena River basin.
Andres Felipe Galeano Moreno, EPM environmental professional, emphasized that the initial objective was not only to know how many species existed, but also to understand how human activities affect aquatic ecosystems. “Knowing which fish exist, how they live, and how their populations change allows us to design measures to prevent, correct, or compensate for impacts,” he said.