Ocean currents are predicted to aid in the spread of the invasive predator further south.
In late 2020, as Ricardo Arajo was preparing for work, his phone rang with a terrifying message: For the first time, a lionfish, an invasive predator, had been discovered lurking nearby the waters of Brazil’s Fernando de Noronha Marine National Park, a biodiversity hotspot and well-known scuba diving location off the country’s northeastern coast. The following morning, the fish was killed, but no one dared to rejoice. The research manager of the park, Arajo, claims, “We knew we were in for a war.”
Though they are native to the Indian and Pacific oceans, lionfish were long ago introduced to the Atlantic. After being discovered in the 1980s off the coast of Florida, they later spread throughout the Caribbean, upsetting coral reefs and other ecosystems by consuming fish that were unaccustomed to the ferocious predator. The spread of the fish was hampered by north-flowing ocean currents, such as the South Equatorial Current, and the freshwater plume produced by the Amazon River, but scientists expected that it would only be a matter of time before it entered Brazilian seas.
They have, however, been concerned by how swiftly the invasion has developed (see map below). From the northern state of Amapá to Pernambuco, which is located just south of the country’s easternmost tip, lionfish have been observed along roughly half of Brazil’s coastline as of March.
According to specialists, the invasion is now moving into a frightening new stage. The fish have moved into regions where the south-flowing Brazil current is present, hastening the spread of larvae that are drifting and endangering large new areas of ecologically rich waters. Luiz Rocha, a Brazilian ichthyologist at the California Academy of Sciences, predicts that they will arrive in [Brazil’s] southern states by the end of this year.
The quickly growing and prodigiously reproducing invasive lionfish have not yet been eliminated by any nation. These traits have led to “an uncontrolled population explosion” off the coast of Brazil, according to Marcelo Soares, a marine scientist at the Federal University of Ceará.
Because of the COVID-19 pandemic and funding restrictions, Soares claims that the initial burst was mostly undetectable to Brazilian researchers. “We were stuck in lockdown, with no money for fieldwork, while lionfish were out there multiplying.” Despite the challenges, a network of scientists monitoring the invasion has confirmed nearly 360 lionfish sightings since 2020.
The Fernando de Noronha archipelago, which is located 350 kilometres off the coast of Brazil, is among the maritime islands about which scientists are particularly concerned about the potential effects on local fish. Numerous small, confined-range native reef fish species are found on these islands, making them “exactly the kind of prey that lionfish love,” according to Hudson Pinheiro, a marine biologist at the University of So Paulo. “The likelihood that lionfish will harm these species is quite high.” He asserts that the worst-case scenario is for some to become extinct.
Around Fernando de Noronha, 170 lionfish have so far been identified, predominantly in shallower reefs. However, they claim that many more are probably reproducing and living in deeper seas. ICMBio, the government organisation in charge of managing the park, wants to involve park visitors and other people in its fight against lionfish. For instance, dive operators are now permitted to kill any lionfish they come across. “We are aware that while it cannot be completely eliminated, it can be controlled. That is our goal, says programme co-director and marine biologist Clara Buck.
Reef scientist Carlos Eduardo Ferreira of Fluminense Federal University advises, “You have to act quickly.” “You can be more effective if you move in quickly.”
Despite these initiatives, researchers predict that lionfish will integrate into the food chain and last a lifetime in Brazil’s marine ecosystem, coexisting in an ecological niche alongside other predators like groupers and snapper, whose numbers have been severely decreased by overfishing. Like in the Caribbean, Ferreira expects that it will be a typical fish in this area.
