让人胆战心惊的放鲨计划 澳大利亚科学家放鲨入海计划让人胆战心惊 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." 用心 爱心 专心1Only 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.用心 爱心 专心2
