Antarctic blue whales have been perceived again in the sub-Antarctic island of South Georgia. An international-team of researchers discovered the animals five decades after whaling (捕鲸业) nearly caused them to disappear forever. “The ocean resources at South Georgia were heavily developed during the early 20th-century industrial whaling,” says lead author Susannah Calderan, an ecologist with the Scottish Association for Marine Science.

Antarctic blue whales were plentiful in the area until whaling began there in 1904, kicking off the beginning of industrial whaling in the Southern Ocean. While hunters originally focused on species that could be easily caught, like the humpback whale, the focus quickly moved to the blue whale. Between 1904 and 1973, 345,775 Antarctic blue whales were killed in the Southern hemisphere (半球）and in the northern Indian Ocean. Around South Georgia, blue whale catches were reported year-round without stopping. Between 1904 and 1971, industrial whaling caused 42, 698 blue whales’ death, Blue whales almost disappeared in these areas.

Researchers studied all Antarctic blue whale data from the last three decades. They examined sightings (目睹)from scientific surveys collected by observers on ships, as well as opportunistic sightings reported by seamen and ship passengers to the South Georgia. They also examined acoustic(声音的）recordings of blue whale.

They found that whale surveys from ships off South Georgia resulted in just one blue whale sighting between 1998 and 2018. But more recent surveys suggest better news. A survey in February of 2020 found nearly 60 blue whale sightings, and several acoustic detections (探测).A total of 41 blue whales have been recognized through photos from South Georgia between 2011 and 2020.

“Their return is very meaningful, as it was widely thought that blue whales at South Georgia might have been hunted beyond a point where they could recover, and might never be seen again in great numbers at South Georgia,” Calderan says. “Our research shows that, populations can recover even from very low levels if they’re given enough protection.”

【小题1】What does the underlined word “perceived” in paragraph 1 mean?

A．Kept.

B．Found.

C．Hunted.

D．Destroyed.

【小题2】What does paragraph 2 mainly want to tell us?

A．The development of industrial whaling.

B．The cause of blue whales’ disappearance.

C．The wide spread of blue whales in the past.

D．The tricks of catching blue whales easily.

【小题3】What did the researchers find through their surveys in South Georgia?

A．There is an increasing return of blue whales.

B．Blue whales are in a more dangerous situation.

C．More and more people like watching blue whales.

D．South Georgia is a good place to watch blue whales.

【小题4】What might be discussed in the following paragraph?

A．The risk of killing whales at higher rates.

B．The sign of Antarctic blue whales’ return.

C．The way of protecting Antarctic blue whales.

D．The effect of the great loss of ocean resources.