澳大利亚科学家放鲨入海计划让人胆战心惊

悉尼麦加里大学的生物学家们指出，澳大利亚新南威尔士州和昆士兰州沿海中的沙锥齿鲨正濒临灭绝，建议从澳大利亚西部或非洲引进一些沙锥齿鲨以保证其正常繁殖。


澳大利亚东海岸地区负责海滩安保的人员对科学家们的这一建议实在无法苟同。来自澳大利亚冲浪救生组织的康奈尔说：“最起码，这些沙锥齿鲨的样子会把游泳或冲浪的人吓坏。它们的大脑不够用，会把人当作鱼一样吃掉。”成年的沙锥齿鲨有10英尺长（约3米）。康奈尔说，海滩救生员一旦有大鲨鱼出现就会立即疏散海滩附近的人群，“我们可没有时间去判断它是什么种类的鲨鱼，它是否会对人构成危险。为确保游人的安全，我们只会不加思索地让人们全部撤离。”


不过，科学家们认为，尽管沙锥齿鲨锋牙利齿的外表很吓人，但它们实际上是性情温和的动物，只有被激怒时才会咬人。麦加里大学的生物学家们说：“沙锥齿鲨的样子看起来很可怕，但它们不是食人的动物。它们露在嘴外的长长尖牙是为了捕捉到光滑的鱼而不是大型的哺乳动物。”


报道说，由于沙锥齿鲨外表凶猛，它们在上世纪六七十年代就被人类大量捕杀。目前，澳大利亚东部水域仅剩300至500只沙锥齿鲨存活。同时，沙锥齿鲨的幼崽在子宫里就互相残杀。沙锥齿鲨有两个子宫，占优势的幼崽将吃掉其同胞，因此沙锥齿鲨每年只能生育1只幼崽，繁殖速度很慢。为了控制其濒危局面，澳大利亚科学家今年初曾计划养殖试管沙锥齿鲨。墨尔本水族馆将尝试对一条七鳃沙进行人工受精，如果试验成功便会将该技术应用在濒危的沙锥齿鲨身上。然而，人工受精沙锥齿鲨也不能避免幼崽在子宫内互相残杀的情况，因此新南威尔士州渔业部门的科学家们又提出了在试管里养殖胚胎鲨鱼的计划，以期从根本上解决问题。


In a scheme that smacks of carrying coal to Newcastle, scientists have proposed
importing sharks to Australia's east coast - causing consternation among tourism
and beach safety authorities.


Researchers say grey nurse sharks are critically endangered in waters off New
South Wales and Queensland and have suggested relocating some specimens from
Western Australia, or Africa, to boost the gene pool.


Biologists from Macquarie University in Sydney insist that grey nurse sharks,
while terrifyingly toothy in appearance, are mild creatures which will bite
humans only if provoked.


However, organisations charged with protecting swimmers and surfers are
unenthusiastic about having more predators in the water.


"Basically they are big fish with big teeth and they scare people," said Sean
O'Connell, of Surf Life Saving Australia, the nation's principal water safety
and rescue authority.


"They don't have very big brains and they could quite easily take a bite at
someone thinking they were a fish."


Grey nurse sharks can grow to 10ft in length and Mr O'Connell said that
lifeguards sighting any large shark off a popular surf beach would automatically
evacuate the sea. "We are not going to make a judgment call based on what sort
of shark it is, or how harmful it is. We would just get people out regardless,"
he said.


Adam Stow, a member of the university research team, said: "They do look fairly
formidable, but they are not people-eaters. Those long, pointy teeth that hang
out of the side of their mouths are designed to catch slippery fish rather than
large mammals."


Only 300 to 500 grey nurse sharks remain in eastern Australian waters after they
were ruthlessly hunted in the 1960s and 1970s because of their ferocious
appearance.