One of the most threatened biomes in Brazil, the Atlantic Forest, now faces a new threat: zebrafish (Danio Rerio) genetically modified glow in the dark.
Although the fish known as GloFish is officially banned in the country, researchers have captured samples in streams from all five surveyed sources in the Paraíba do Sul River Basin, in the southeastern region. The basin covers 55,500 km² of the states of São Paulo, Minas Gerais and Rio de Janeiro, and is the watershed most affected by human activity in Brazil.
“I am very concerned that these exotic fish could have serious environmental impacts, such as competition for food. [com espécies locais] and preys on local fish,” says Andre Magalhães, a biologist at the University of São João del Rey in Minas Gerais and lead author of a recently published study.
He says some native fish could become extinct through these and other introduced species. “In addition to many species of exotic fish, we now have exotic hybrid fish and, even worse, genetically modified exotic fish like transgenic zebrafish.”
This study, Magalhaes says, is the first of its kind to explore the life strategies of transgenic zebrafish (Danio rerio) in the natural environment. The researcher explains that this species feeds on insects and zooplankton, which also supports the local fish, which puts them in direct competition.
Magalhães says this means the springs are becoming vulnerable to alien species invasion. Also, while GloFish (which includes other species of fish genetically modified to gain fluorescence) is widely believed to be sterile, the study found that these fish were breeding in two springs. In one of them, Corrego Quiroga, in Divino (MG) municipality, Magalhaes said, “they breed every month of the year.”
This exacerbates an already alarming situation, he says: “The risk that these exotic fish could exterminate native fish is real and will only grow in size unless authorities take steps to prevent them from escaping from their breeding grounds.”
Jan Vitol, a fish expert at Parana University, who was not involved in the study agrees: “I am very worried [com as descobertas]”The arrival of genetically modified fish in these watersheds is a shot in the dark,” he told Mongabay.
In the late 1990s, the National University of Singapore created the first transgenic fish by adding red and green fluorescent protein genes from anemones and jellyfish to wild zebrafish (Danio rerio), a species native to southern Asia that is popular in the aquarium trade. The American company Yorktown Technologies acquired the marketing rights from university scientists and began to produce and sell fish under the name GloFish.
Since 2001, when Yorktown was founded, the company’s genetic engineers have been producing colorful versions of several species of aquarium fish, giving them flashy names such as “electric green,” “galactic purple”), “Sunburst Orange” (something like “Sun Orange”” ) and “Starfire Red” (something like “Star Red”).
The US Food and Drug Administration (FDA) has shown little concern about the environmental risks posed by fish. “There is no evidence that genetically modified zebrafish pose a greater risk to the environment than unmodified fish, which has long been sold in the United States,” the agency stated in 2003. “In the absence of clear public health risks, the FDA sees no reason to regulate this particular fish.”
A study published in 2015 appears to confirm the FDA’s assessment. Researchers at Purdue University in the US studied more than 18,500 adult zebrafish, both wild and fish, from 18 groups over 15 generations. They found that although female zebrafish preferred genetically modified males as pairs, wild males were much more aggressive.
And that’s what he won. In a video interview, the wild males expelled the fluorescent fish and took all the females, leading to the extinction of the GMOs, William Muir, the study’s senior author and a biologist who performed the risk assessment for the Food and Drug Administration, said in a video interview. Mongabay: The offspring of wild males is 2.5 times greater than that of a glovefish.
“If we produce a genetically modified organism that is less viable in the environment, evolution will take care of removing it,” Muir says. “Nature experiments with mutations all the time, and only keeps the best of it.”
He also thinks the Brazilian scientists are exaggerating the risks and says the new research is “almost a nothing study. They were able to publish it in a high-quality journal because it’s impressive.” Muir says that while there are reasons for concern, the reason is not “because a genetically modified fish has been found, but because the area is experiencing an invasion of exotic animals.”
But Magellan does not agree. “Professor Muir’s research was done in the lab, while ours was done in nature,” he said. “In the lab, you can control the variables, but in nature, you can’t.”
They are unsure, for example, that genetically modified species will be lost, especially in an ecosystem where there are no native predators. He horrifies the idea of fluorescent fish breeding in the Atlantic Forest, Magalhaes says.
The study recommends installing simple devices such as nets in fish ponds to prevent or reduce GloFish escape. If they manage to escape, you must build ponds to hold native predatory fish, such as toothfish (Oligosarcus hepsetus), which feed on zebrafish before they reach a natural waterway. The study also calls for incentives for local ornamental breeding sites to breed native species in the area, rather than exotics such as zebrafish, and says a total ban on genetically modified fish should be imposed in Brazil, as recommended by Ibama.
According to Magalhaes, the import of genetically modified fish was banned by Ibama in 2017, but the page on the agency’s website detailing the ban, which he viewed in March 2020, has disappeared. IBAMA did not respond to requests for clarification contained in the report. However, the IBAMA website provides evidence that the ban on the import of GM fish is still in effect, noting that the list of species that can be legally imported does not apply to GM fish.
However, transgenic fish continues to be advertised on Brazilian websites. On this page, a pink GloFish known as “Paulistinha Rosa” is advertised for sale by a Piauí aquarium shop. The property did not respond to Mongabay’s requests for comment. Other suppliers are posting videos of genetically modified fish on Facebook, like this one from a store in Manaus, to attract consumers. In a phone message, MP Ornamental Fish said that the genetically modified aquarium has only a decorative function and that it does not sell fish.
(by Sue Branford)
Notícias da Floresta is a column containing reports on sustainability and the environment produced by the Mongolian News Agency, published weekly in ECOWAS. This report was originally published on the Mongabay Brasil website.