"If there's one thing in my career I'd like to be proved wrong about, it's the baiji," said Sam Turvey of the Zoological Society of London, using another name for the Yangtze River dolphin.
Turvey spent almost 3 months this year interviewing Chinese fishermen in vain for sightings of the long-snouted dolphin, which has not been seen since 2002. Some colleagues in China are still looking.
The baiji was almost declared extinct in 2006 after an acoustic and visual survey of the river turned up nothing. Then, a blurry video gave experts pause, and it was rated "possibly extinct."
About 300 plant and animal species, including the Christmas Island shrew and the Venezuelan skunk frog are also "possibly extinct," the worst category short of extinction, according to the International Union for Conservation of Nature's (IUCN) Red List.
If Turvey's study turns up no firm evidence, it will likely push the Yangtze River dolphin into the "extinct" column, said Mike Hoffmann, who manages a global project to assess species for the IUCN and Conservation International.
It would be the first "megafauna" mammal -- one weighing more than 100 kg (220 lb) -- to die out since the Caribbean monk seal in the 1950s.
"To say something is extinct requires quite a lot of proof, of negative evidence, and may take many years to collect," said Craig Hilton-Taylor, who manages Red List.
Scientists working on the "possibly extinct" list rummage in the undergrowth for rare plants, frogs or rats, set up night-time traps for bats or moths, or scour the seabed for corals.
Some experts liken the difficulties to "proving" that the mythical Loch Ness Monster does not exist.
No comments:
Post a Comment