Inside a fishbowl, the goldfish — a species of carp native to East Asia, bred for aesthetic delight and traditionally believed to bring good fortune — is among the easiest of pets to keep. But released into the wild, the seemingly humble goldfish, freed from glass boundaries, can grow to large proportions. They can even kill off native marine wildlife and help destroy fragile and economically valuable ecosystems.
“They can eat anything and everything,” said Christine Boston, an aquatic research biologist with Fisheries and Oceans Canada. Over the past several years, Ms. Boston and her colleagues have been tracking invasive goldfish in Hamilton Harbour, which is on the western tip of Lake Ontario (安大略湖), about 35 miles southwest of Toronto.
Their study, published last month in the Journal of Great Lakes Research, could help pinpoint goldfish populations for culling, said Ms. Boston, who is the lead author. “We found out where they are before they start spawning (产卵),” she said. “That’s a good opportunity to get rid of them.”
The fast-growing female goldfish, Ms. Boston noted, can also reproduce several times in one season. “They have the resources,” she added, “and they can take advantage of them.” Their football-shaped bodies can swell to a size that makes them too large a meal for predators (捕食者) — up to about 16 inches long. The feral goldfish are also destructive, uprooting and consuming plants that are home to native species.
Nicholas Mandrak, a professor of biological sciences at the University of Toronto Scarborough, studies in the “dramatically increase” of the wild population in the past two decades. Their spawning explosion, he said, resulted partly from people in densely-populated areas releasing pets in urban ponds. He added, environmental managers tend to forget the goldfish. “They just assume, ‘It’s been there for 150 years — there’s nothing we can do about it.’”
The problem is not unique to Canada. In Australia, a handful of unwanted pet goldfish and their offspring took over a river in the country’s southwest. And the discovery of football-size creatures in a lake in 2021 even led British officials to beg their citizens: “Please don’t release your pet goldfish into ponds and lakes!”
People wrongly believe that because goldfish are “small and cute” they won’t pose a problem when released into the wild, said Anthony Ricciardi, a professor of invasion ecology at McGill University in Montreal.
Goldfish, he added, are just a small part of a vast invasion of non-native species whose outcomes can be unpredictable, and in some cases, are worsened by climate change.
“Under human influence, beasts are moving faster farther in greater numbers, reaching parts of the planet they could never reach before,” he said. “We’re talking about the redistribution of life on Earth.”
8. Which of the statements about the goldfish is correct?
A.Their place of origin is Canada. | B.They are capable of reproducing. |
C.They will grow well over 16 inches. | D.They only invade Lake Ontario. |
9. What does the underlined word in paragraph 3 mean?
A.Killing | B.Controlling | C.Catching | D.Observing |
10. All of the following statements are the reasons for the spawning explosion
Except:
A.Citizens wrongly set free the fish. | B.Climate change has a negative impact. |
C.The environmental management is absent. | D.The food increases in habitats. |
11. What is the best title for the text?
A.Now goldfish are turning into wild monsters. |
B.Now goldfish are on the way to become a global issue. |
C.Now goldfish are attracting scientists to study in. |
D.Now goldfish are threatening the Great Lakes. |