英語(yǔ)聽力：自然百科 溫室效應(yīng)幫上忙？

Climate change is normally bad news for endangered species, but in the case of Australia’s Grey Nurse Shark, some scientists suggest it might actually help their fight for survival.

The Grey Nurse Shark is one of Australia’s most critically endangered species. A survey in 2002 estimated there were fewer than 500 in the critically endangered population living off the country's east coast. On the west coast, they are vulnerable but not yet endangered. Australia’s two Grey Nurse Shark populations have been isolated from each other for more than 100,000 years. Until now the waters separating the two populations have been too cold for the sharks to come into contact with each other. But as temperatures rise due to global warming, warmer waters could result in the sharks inhabiting the same areas. If the shark populations unite, theextinction risk may be reduced

Suddenly you’re gonna get an influx of new genes coming into the population which means that they perhaps won't be as susceptible to disease outbreaks, etc. In addition to that, of course the population, as a whole, grows.

But experts remain concerned about other environmental threats to the sharks, like commercial and recreational fisheries, ecotourism, overfishing for their fins, the aquarium trade and beach meshing.

“On the long term, climate change may be lending a helping hand to the survival of Grey Nurse Sharks, but we can’t have made sure if they get there first, and that means solving the near term management problems. And the greatest near term threat is the capture of them--the sharks on hooks.”

Grey Nurse Sharks became one of the first protected sharks in the world when New South Wales, Australia declared them a protected species in 1984. They are now also safeguarded by fishing legislation in at least four sites in southeast Queensland.