Lionfish have been migrating (迁徙) south for years. They were first caught in the Gulf of Mexico, likely released from the aquarium trade, in 1985, and quickly expanded into the US East Coast and the Caribbean. They reached South American coastlines around 2010.

But the species stopped around Venezuela and Trinidad and Tobago. For 10 years, freshwater flowing from the Amazon River into the Atlantic and a gathering of currents acted as geographic (地理的) barriers, stopping the fish from continuing south. But around 2020, lionfish began slip-ping under the barrier and heading south.

Now, dozens of lionfish have been spotted along 150 miles of Brazil’s coastline, according to a new study in Frontiers in Marine Science. Between March and May, when the water was clear enough to track the fish, researchers and fishers documented 72 individuals there, which suggests they have likely established new, successful populations.

Since March 2022, lionfish already managed to cover 700 kilometers of coastline, says Marcelo Soares, a marine ecologist and lead author of the new study. He also reported the number of individuals is now above 300.

For many scientists, the question wasn’t whether the fish species would continue moving south, but when. “We knew once they made it through the barrier at the Amazon, they would spread like fire,” says Osmar Luiz, an aquatic ecologist at Australia’s Charles Darwin University.

While efforts to fully get rid of lionfish may be useless, efforts to reduce their populations help limit damage to native species. Luiz says that the next important step is to track lionfish as they move and try to prevent them from establishing new populations. For the native species of Brazil, this fight is a matter of survival, Luiz says.

【小题1】Why did lionfish appear in South American coastlines?

A．They were sent there by currents.

B．They were brought there by Americans.

C．The aquarium staff released them in South American coastlines.

D．They migrated there after being spotted in the Gulf of Mexico.

【小题2】What once stopped lionfish from moving south?

A．Natural barriers.

B．Sea pollution.

C．Fishing activities.

D．The aquarium trade.

【小题3】What are scientists concerned about?

A．It’s very difficult to track them.	B．Whether lionfish will continue moving.
C．It’s impossible to reduce their populations.	D．The spread of lionfish will destroy local species.

【小题4】In which section of a newspaper can we probably find this text?

A．Health.

B．Nature.

C．Technology.

D．Business.