墨西哥及紐西蘭的海豚瀕臨滅絕 | 台灣環境資訊協會-環境資訊中心

墨西哥及紐西蘭的海豚瀕臨滅絕

2012年07月13日
摘譯自2012年7月10日ENS巴拿馬市報導;沈瑞筠編譯;蔡麗伶審校

國際捕鯨委員會(IWC)上週在巴拿馬市的會議中提出警告,除非將流刺網移出牠們的棲地,否則兩種海洋哺乳動物將走向滅絕。

國際捕鯨委員會的科學委員會向89個會員國代表表示,墨西哥小頭鼠海豚及世界上現存數最少的鯨豚-紐西蘭毛依海豚-皆列於極度瀕危動物名單,並面臨即將滅絕的風險。

小頭鼠海豚因漁網纏繞而死亡(圖片來源不明)根據科學委員的報告,這兩種海豚都因為流刺網捕魚意外造成的混獲而受威脅。若要拯救牠們的族群,在這兩種海豚的棲地全面禁止使用流刺網是必要的。

國際捕鯨委員會的會員國認為墨西哥及紐西蘭政府應立刻採取所有可能的行動以防止這兩種海豚滅絕。

奧地利代表Michael Stachowitsch認為,「現在須先將外交場合逐步擬定策略、講究細微末節先置於一旁,必須展現毫不妥協的具體行動,」

墨西哥:小頭鼠海豚約僅存220頭

根據美國國家海洋暨大氣總署資料,墨西哥小頭鼠海豚僅棲息於墨西哥加利福尼上灣,2008年的數據呈現僅存220頭,而牠們的族群量仍在下降中。據估計,每年約有30-85頭因漁具纏繞而死亡。其他對該物種的可能威脅還有環境污染、棲地退化、因數量過少的近親繁殖問題等。

國際捕鯨委員會科學委員的報告強烈建議:如果要避免該物種的滅絕,則必須立即於加利福尼亞灣全面禁用流刺網。

一些國家贊同科學委員會的觀點,並承認墨西哥的努力,敦促盡快行動。國際捕鯨委員會在討論總結時表示:「墨西哥理解和承認這些議題。」

墨西哥已成立國際委員會來復育小頭鼠海豚且在加利福尼上灣成立生物保留區。

世界自然基金會海龜於海豚事務經理Aimee Leslie表示,「墨西哥藉由禁止在鼠海豚棲地使用流刺網,掌有拯救這個物種的能力。」

Leslie指出,「目前,被漁具意外捕獲是鯨豚最大的威脅。據估計每年有30萬頭以上的鯨豚因各式漁具纏繞而死亡,也就是說每兩分鐘就有一頭鯨豚因混獲而死亡。」

紐西蘭:賀氏矮海豚減少到1/4

紐西蘭海域的毛依海豚(Photo courtesy NZ Dept. of Conservation)另外,國際捕鯨委員會科學委員認為紐西蘭應採取立即措施來阻止他們的原生海豚數量下降,指出目前的保護措施並不足以涵蓋不當的捕魚方式。

自從1970年間引進了尼龍魚網後,賀氏矮海豚(Hector's dolphin)數量就由3萬下降到約莫7千。而情勢對賀氏矮海豚的亞種毛依海豚更為不利,超過94%的毛依海豚已經消失,目前只剩下紐西蘭北島西岸有非常小的族群。

毛依海豚只剩55頭超過一歲的個體,少於20頭有繁殖力的雌性,族群量以每年約3%的速度下降中,正面臨立即滅絕的危機。

德國保育團體德國鳥會在國際捕鯨委員會中發表一份報告,強調保護這個物種的重要性。來自德國鳥會的Barbara Maas博士表示「賀氏矮海豚和毛依海豚棲息在沿海深度100米的水域。紐西蘭政府已受到來自漁業利益團體堅決反對任何保育海豚措施的壓力;所以我們很高興國際捕鯨委員會肯定科學家及保育者的呼籲:禁止在100米深的水域使用流刺網及底拖網。」

紐西蘭告知委員會,目前已擴展現有的拉纳奇海岸(Taranaki coast)保護區來改善現況。但紐西蘭沒有提到的是,這個措施是暫時的,且並未納入底拖網及並沒有包含大部分的海豚棲地。

紐西蘭保育團體森林與鳥類保育協會表示,政府的措施仍未充分防止毛依海豚滅絕,因為其他重要地區仍完全不受保護。

森林與鳥類保育協會經理Kevin Hackwell表示,「魚網的禁令應延伸到所有國家級瀕危毛依海豚曾發現的區域,包含所有的港口及離岸100米深等高線範圍。我們必須完全移除所有牠們棲地的威脅,我們現在需要實行更強而有力的措施,而不是等待今年底威脅管理計畫通過審查。」

Hackwell說明,指派觀察員到商業漁船上來防止海豚被魚網絞死能發揮的效益有限。「強迫每艘船都有觀察員隨行本質上是好的,這是對的努力方向。但這無法阻止海豚的死亡,這只能讓我們知道我們抓到了多少海豚。」

國際捕鯨委員會的科學委員會審議的研究表明,保護區過小難以發揮效用,流刺網及拖網淨空區的推展過程又過於緩慢。復育海豚族群是紐西蘭政府及國際間的義務。

科學委員會今年的優先議題是審查發現於北太平洋和印度洋北部的10種喙鯨。這些族群並未被完全瞭解,而學術團體認為目前牠們的族群量由於軍事聲納、石油及天然氣勘探、漁網混獲等原因而非常脆弱。

委員會也注意到,在歐洲貝爾海(Belt Sea)及波羅內海,混獲及其他危急港灣鼠海豚族群量的威脅,它敦促建立有效的監測和改善措施。

他也關注受到混獲影響族群量的巴西的拉河豚,目前正由國加級的復育計畫贊助。拉河豚是世界上最小的海豚之一,拉河豚是4種江豚中唯一住在海洋環境中的,是拉河豚科中唯一的成員。

科學委員會長期關注現存的的江豚狀況,今年額外關注們兩種亞馬遜江豚(亞馬遜河豚及土庫海豚)除了其他已知威脅外,尚面臨巴西獵殺它們作為餌料的處境。這部分收到了許多建議,巴西及其他政府表示他們採取行動的意願。

科學委員會對巴基斯坦的恆河豚及柬埔寨的伊河豚的保育成效表示讚揚。

目前唯一因人類活動而消失的海洋哺乳動物是中國長江江豚,2006年由國際捕鯨委員會宣布已滅絕。

Marine Mammals in Mexico, New Zealand Face Extinction
PANAMA CITY, Panama, July 10, 2012 (ENS)

Extinction is imminent for two marine mammal species unless their habitat is immediately cleared of gillnets, the International Whaling Commission was warned last week at its meeting in Panama City.

The IWC's Scientific Committee told hundreds of delegates from the 89 IWC member governments that Mexico's vaquita porpoise and the world's rarest marine cetacean, New Zealand's Maui's dolphin, are both Critically Endangered and at immediate risk of extinction.

Both marine mammals are threatened by accidental bycatch in gillnet fisheries. A total ban on the use of gillnets in the entire ranges of both populations is needed to secure their survival, according to the Scientific Committee's report.

IWC member governments urged Mexico and New Zealand to take all possible measures immediately to save these animals from extinction.

"It's time for diplomatic niceties and step-wise strategies to take a back seat to immediate, concrete action with no compromise," said Michael Stachowitsch, delegate of Austria to the IWC.

The vaquita porpoise, Phocoena sinus, clings to existence in the Upper Gulf of California, Mexico. There were only about 220 animals in 2008 and the population continues to decline. It is estimated that at least 30-85 individuals are taken incidentally in fishing nets each year. Other possible threats to this species include environmental pollution, habitat degradation, and inbreeding due to low population numbers, according to the U.S. National Oceanic and Atmospheric Administration.

The IWC's scientific report strongly recommends that, if extinction is to be avoided, all gillnets should be removed from the upper Gulf of California immediately.

A number of countries echoed the Scientific Committee's concern and while recognizing Mexico's efforts to date, urged action as soon as possible. "Mexico understood and recognized this concern," said the IWC in a summary of discussions.

Mexico has established the International Committee for the Recovery of the Vaquita as well as a bio-reserve in the upper portion of the Gulf of California.

"Mexico has the power to save this unique species by banning all gillnets in vaquita habitat," said Aimee Leslie, WWF's marine turtle and cetacean manager.

Incidental capture in fishing operations is the biggest threat to cetacean species today, said Leslie. "It is estimated that more than 300,000 whales, dolphins and porpoises die each year from entanglement in many types of fishing gear, which is an average of one cetacean killed by bycatch every two minutes."

The IWC Scientific Committee urged New Zealand to take immediate steps to arrest the decline of its only native dolphins, pointing out that current protection measures are inadequate in terms of the area and the fishing methods they cover.

Since the introduction of nylon filament nets in the 1970s, Hector's dolphin numbers have dropped from 30,000 to around 7,000. The situation for Maui's dolphins, Cephalorhynchus hectori maui, a subspecies of Hector's dolphins, is even worse. More than 94 percent are already lost and Maui's dolphins are now confined to very small remnant population on the west coast of New Zealand's North Island.

With just 55 survivors older than one year, fewer than 20 breeding females, and an annual decline of around three percent, Maui's dolphins are facing imminent extinction.

"Hector's and Maui's dolphins inhabit coastal waters up to a depth of 100 meters," says Dr. Barbara Maas, of the German conservation group NABU International, which released a report highlighting the urgent need to protect this species at the IWC.

"The New Zealand government has been exposed to fierce pressure from fishing interests, which strongly oppose any measures to protect the dolphins. We are therefore delighted that the IWC has confirmed what scientists and conservationists have been calling all along: a ban on gillnets and trawling in waters up to 100 meters depth," said Maas.

New Zealand informed the commission that it is extending the existing protected area on the Taranaki coast in order to improve the situation.

Yet the New Zealand delegation failed to mention that these measures are temporary, they do not include trawl fishing and do not apply to most of the dolphins' habitat.

The New Zealand conservation group Forest & Bird says the government's move still does not adequately protect Maui's dolphins from extinction because other significant areas remain completely unprotected.

Forest & Bird Advocacy Manager Kevin Hackwell said, "The set net ban needs to be extended to all regions where these nationally-critical Maui's dolphins are found. That includes all harbors and offshore to the 100 meter depth contour."

"It's imperative we remove the threat by adopting a ban that completely covers their habitat," said Hackwell. "We need stronger measures to be implemented now, not at the end of the year after the Threat Management Plan has been reviewed."

Hackwell says requiring observers on commercial fishing vessels will do little to actually stop dolphins from dying in set nets. "It's going to force fishers to put observers on their boats, which is good. It's a step in the right direction. But it won't stop dolphins being killed. It will just mean that we'll know how many we've caught."

Research considered by the IWC's Scientific Committee shows that protected areas are too small to be effective, and progress in extending gillnet and trawl net free areas has been too slow to achieve recovery as part of New Zealand's national and international obligations. .

The Scientific Committee's priority topic this year was a review of the 10 beaked whale species found in the North Pacific and northern Indian Ocean. These populations are not well understood and the scientific body stressed their vulnerability to military sonar and to seismic surveys for oil and gas and the problem of bycatch in fishing nets.

The Committee also noted bycatch in fishing gear and other threats affecting harbor porpoise populations in European waters of the Belt Sea and the inner Baltic. It urged development of effective monitoring and mitigation measures.

It expressed concern over high bycatches in fishing gear of a population of Franciscana dolphins, pontoporia blainvillei, in Brazil and endorsed a national recovery plan. One of the world's smallest dolphins, the Franciscana is the only one of the four river dolphin species living in the marine environment and the sole member of its family.

Longstanding concerns exist over the status of river dolphins. The Scientific Committee this year had additional concerns over intentional killing for bait in Brazil of two Amazon species, the botu and the tucuxi, in addition to other threats they face. It made a number of recommendations and Brazil and other range states indicated their willingness to act on these.

The Scientific Committee was pleased to hear of conservation efforts for the Indus River dolphins in Pakistan and the Mekong River population of Irrawaddy dolphins in Cambodia.

The only known loss of a mammal species from human causes was the Chinese baiji, or Yangtze river dolphin, which was declared functionally extinct by the IWC in 2006.