Researchers discover rare type of golden catfish in Tijuca Park

Three researchers from the Laboratory of Systematics and Evolution of Teleosteous Fish, from the Biology Institute of the Federal University of Rio de Janeiro (UFRJ), found, for the first time, in the rivers and waterfalls of the Tijuca National Park, in the capital of Rio de Janeiro, three specimens of golden catfish fish. The discovery was published last year in the New Zealand magazine Zootaxaa world reference in zoology, by researchers Paulo Vilardo, Axel Katz and Wilson Costa.

According to Axel Katz, the team has been researching these coastal fish for several years and realized that those from São Paulo had DNA very similar to the species from Rio, although the color was a little different. They then focused on a specific fish that had a more differentiated color.

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Paulo Vilardo added that several fieldworks were carried out in the Tijuca Forest. “Most of the specimens found were of a mottled, or sealed, pattern, with black transverse bands on the body. It is a pattern of this type that is found in several coastal basins in Rio de Janeiro, São Paulo and Paraná.”

At one point, however, in a specific location in the Tijuca National Park, completely yellow, or golden, specimens were found. “Then curiosity hit to see if this animal wasn’t the same one that occurs in São Paulo. DNA tests were carried out using the PCR (or Polymerase Chain Reaction) technique, and it was concluded that the goldfish from the Tijuca Forest were the same as those from São Paulo.”

Furthermore, it was found that the spotted pattern is also the same species as the golden one, but this one has a very rare color and is found very few times,” said Vilardo. To date, there are records of only seven or eight individuals of golden catfish in the three locations in the country. “It is very rare for this color to be recorded in this animal.”

Importance

In addition to identifying that the freshwater golden catfish occurs in all areas of the three states, with the largest distribution, Paulo Vilardo reinforced that the fish has a rare pattern. A third factor is that the conditions of the Tijuca Forest are very good, and the conservation of the rivers is very positive.

“These fish with a rare color pattern, both here and in São Paulo, were found in ecological reserve areas. An interesting point is to see that, in a very preserved place, it was possible to find this rarest pattern.” What researchers still don't know is whether the discovered fish is more sensitive than the others, Vilardo said.

For the Atlantic Forest, Alex Katz highlighted that the importance is that most of these fish feed on insects, basically mosquito larvae. “They are very good at controlling mosquito populations, which are vectors of many diseases, such as dengue fever and yellow fever. Fish also like to climb waterfalls and reach inaccessible places. Therefore, they are great predators of mosquitoes that appear in rivers and waterfalls. Sometimes, at 1,500 meters of altitude, we can find some catfish. They occur in very high regions due to their ability to climb rocks.” According to the researchers, the discovery reinforces the importance of preserving freshwater bodies in Rio de Janeiro.

O Trichomycterus jacupiranga is a species of catfish, a popular freshwater fish that occurs in several places in South America. Most have a yellowish body with black bands running across the back, as well as other variations in the pattern of spots and marks. The difference in the work of the UFRJ researchers was to identify and prove that the golden specimens found in the Tijuca National Park were of the same popularly known species, but with a color variation unknown in Rio de Janeiro waters. Until then, such specimens had only been recorded in the Ribeira do Iguapé River region, on the border between São Paulo and Paraná.

Paulo Vilardo informed that, in addition to continuing research on golden catfish, the focus will now be on other groups of fish, aiming to find new rare species in the Tijuca Forest. Axel Katz added that one of the objectives is to locate lambaris again in the microbasins of the region, the last record of which dates back to 1880, in the Tijuca National Park, where the species was described for the first time. “Finding the lambari would be very important because this is the place where it was described.”

Also, the search can find different fish. “In the Tijuca Forest there is a lot to be discovered,” he said.

Preservation

A discovery of this type only “strengthens efforts to conserve Tijuca National Park,” said the head of the unit, Viviane Lasmar. “Each time we have research results that demonstrate how much the park has elements and issues relevant to conservation, this makes us take a more careful look at the issue of biodiversity.”

A Brazil Agency, Viviane recalled that the park has intense public use and the information from the research serves as guidance for the necessary planning actions, including to help with the issue of conservation as well. “It’s not just research for research’s sake, but it’s how to apply the results into effective actions, for better use of the territory as a whole and even to raise awareness among visitors.”