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大吴 |
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2004-07-19 17:39:28 |
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北京 |
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主题：保护鲨鱼请您嘴下留情
内容：
保护鲨鱼请您嘴下留情
北京青年报 2004年07月19日
最新报告：“濒危鲨鱼名单”又添10种———
前几天，若干来自世界各国的鲨鱼专家学者云集美国佛罗里达，商讨如何保护鲨鱼种群。大白鲨一向令人谈“鲨”色变，不过，对大白鲨种群来讲，人类更令它们不寒而栗。大白鲨多见于南非、美国加州和澳大利亚的海岸线。近二十年来，市场上的鱼翅交易已像火箭般蹿升，没有任何控制。每年有数百万头鲨鱼惨遭宰割，甚至有些渔民捕获鲨鱼、砍掉鱼翅后，再把血淋淋的鲨鱼扔回海洋。
近日，一位资深科学家在南非约翰内斯堡宣布，由于全球海洋环境的进一步恶化，更多鲨鱼濒临灭绝。
随着对鲨鱼鱼翅市场需求的不断攀升，渔民对鲨鱼过度捕捞，导致鲨鱼种群的生存面临威胁，全球鲨鱼数量急剧下跌。瑞士“国际自然保护联合”（IUCN）的“濒危物种名单”一直是全球范围内备受尊重的野生资源保护指数之一，是世界各地环保人士和研究人员的重要参考。现有的“IUCN濒危鲨鱼”名单上，又新增加了至少十种鲨鱼，其中包括大白鲨、新英格兰刺鲛和墨西哥湾白吻鲨。至此，濒临灭绝的鲨鱼种类增加到了82种。目前，世界上75%的海洋被鉴定为过度渔业受灾区。
环保人士纷纷呼吁：保护鲨鱼！请您嘴下留情。
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小平 |
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2004-07-20 11:10:13 |
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泰国普吉 |
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跟贴：Dangerous or endangered? - Simon Rogerson, February 2003
A major new report has painted the most detailed picture yet of the cataclysmic effect of longline fisheries on shark populations.
A study on the shark population of the northwest Atlantic has suggested that several key species are heading towards extinction. Scientists from Dalhousie University in Nova Scotia, Canada have found that populations of some of the major predators have plummeted to less than a quarter of their former sizes.
The Dalhousie team analysed catch data in the northwest Atlantic of six oceanic species ? plus three coastal sharks ? from 1986 to 2000. ‘We estimate that all recorded shark species, with the exception of the makos, have declined by more than 50 per cent in the past eight to 15 years,’ a spokesman said.
While fish such as cod and haddock can reproduce fairly fast ? possibly by up to 30 per cent a year ? sharks are apex predators and breed more slowly. Some take 15 years or more to reach sexual maturity and some have gestation periods of up to two years.
The authors of the report said they believe populations of thresher sharks are now so low, they are close to commercial extinction. ‘Our results show that overfishing is threatening large coastal and oceanic sharks in the northwest Atlantic...The magnitude of of the declines estimated here suggests that several sharks may also now be at risk of large-scale extirpation [destruction].’
Traditional measures for conservation may not be enough to save some sharks, according to the report. The researchers used models to analyse the implications
of large-scale marine reserves for shark conservation, and say the results show that reserves ‘can indirectly cause harm if fishing effort is merely displaced’.
According to the Dalhousie team, conservation initiatives must explicitly consider impacts on the whole group of species. ‘Emphasis on single-species conservation, without controlling effort, simply shifts pressure from one threatened species to another and may actually jeopardise biodiversity,’ the report warns.
Sarah Fowler of the Shark Trust said that the report had confirmed her worst fears. ‘Overfishing is not only driving large coastal species towards extinction, but also depleting oceanic shark stocks ? vital species for maintaining the stability of marine ecosystems.’
Many shark species are highly migratory, and spend time in waters where they are afforded no legal protection. The Dalhousie team has reported a 60 per cent decline in blue sharks in the north west Atlantic, but their numbers may well have been affected by the Spanish longline fisheries operated in the north east Atlantic ? mounds of blue shark carcasses are regularly seen in the fish markets of northwest Spain.
‘Sharks are non-quota species and with the decline of the traditional commercial fish stocks they are coming under increased pressure as an alternative catch,’ Fowler told DIVE. ‘But at what stage does a species stop being classed as a by-catch? It is clear that shark numbers are decreasing at an alarming rate, and on a global scale.’
Of the species monitored by the Dalhousie team, the figures for those sharks facing the biggest decline over the 15-year period are shown on the photographs above and right.
• The Shark Trust is campaigning for a global ban on on shark finning and is calling on divers to support the cause by signing an online petition to be found at www.sharktrust.org
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小平 |
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2004-07-20 11:11:54 |
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泰国普吉 |
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跟贴：?鱼有多危险?
一份有晷西北大西洋海域?酤?量整查?告指出，其中部份?酤品肺正面乓睫肺，Nova Scota Dalhousie University的科?家指出,在加拿大呃些???食者的?量急?下降了25%．
Dalhousie的研究人?，於1986至2000年期殓，在西北大西洋海域?六肺深海和三肺近岸品肺的?酤捕?所得??作出分析．办言人表示：「我???所得，除了Makos外?，近十五年?所有?酤品肺?少了50%」.
部份酤?如魈酤等因繁殖力蒉?，可哌每年30%，所以?铨不大． 但?酤是食物?中的???食者，繁殖力蒉慢，部份品肺要１５?才有交配生殖能力而孕育期樘哌?年．剐者相信Thresher ?酤?量?低，已到哌睫肺肓段．
?告亦锢示，??蒉保守的保育行?可能只是杯水?薪，而?方面局部的?禁捕??酤?不足?，必?有系靳地大??作出海洋的??保育才能有成效．跟?Dalhousie的研究小酵警告，如果保育?酤只局限於某些品肺，那只?是深海一粟和做成生?不平衡而引至海洋樘哞的畸型办展．
我?的劫?是，咿度的捕??酤正威名深海和沿岸的酤?量，也反影部份品肺?面乓重大被?绝危?．
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小平 |
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2004-07-20 11:36:01 |
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泰国普吉 |
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跟贴：驰骋在这星球几亿年,作为食物链的顶层生物,不受大自然演变影响也?有把其他生物全吞噬掉.
只因这几十万年出现了人类这一顶层生物,以前所未见的发展步伐,看来会在短短几百年中把她们从这星球中毁灭. 若不幸成功的话,会对鲨鱼和海洋生态做成极大伤害,相信我们也不能幸免於难.
少少补充: 上文提及 ". . . 每年有数百万头鲨鱼惨遭宰割，甚至有些渔民捕获鲨鱼、砍掉鱼翅后，再把血淋淋的鲨鱼扔回海洋."
据不少海洋科研和鱼翅贸易数据所得,每年遭杀掉的鲨鱼应在五千万至一亿之间.
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