美國湯碗驚現瀕危鯊魚魚翅 | 環境資訊中心

美國湯碗驚現瀕危鯊魚魚翅

2012年08月21日
摘譯自2012年8月14日ENS美國,華盛頓特區報導;李子昂編譯;蔡麗伶審校

研究人員在全美14個城市收集有魚翅樣本。(皮尤環境組織提供)在美國各地城市魚翅湯的基因檢測中,發現八種瀕危和受威脅鯊魚的DNA。這是第一次全美國的魚翅湯調查,分析了14個城市中的亞洲美食,並在其中13個城市的湯碗中檢測出有滅絕危險的鯊魚物種。

調查人員在波士頓的一碗樣本中,發現了路易氏雙髻鯊(scalloped hammerhead shark,又稱紅肉ㄚ髻鯊)的魚肉,該鯊魚是世界自然保育聯盟瀕危物種紅皮書(IUCN Red List of Threatened Species)列為「瀕危」的物種。

為了得出結論,科學家們分析了阿布奎基(Albuquerque)、亞特蘭大、波士頓、芝加哥、丹佛、勞德代爾堡(Fort Lauderdale)、休斯頓、拉斯維加斯、洛杉磯、紐約、奧蘭多、舊金山、西雅圖與華盛頓特區等地的魚翅樣本的DNA。丹佛是唯一沒有檢測出屬於國際自然保護聯盟列為瀕危、易危(Vulnerable)或近危(Near Threatened)物種魚翅的城市。

某些遭鯊魚攻擊的倖存者,現已成為全球保育鯊魚的倡導者,並幫忙為該調查收集樣本。關於倖存者及魚翅湯調查的故事,於美國東部時間8月15日晚上9點的Discovery節目「鯊魚的奮鬥(Shark Fight)」中播出。

查普曼博士。(IOCS提供)調查小組領導人之一的查普曼博士(Demian Chapman)表示,「DNA檢測再次證實,多種鯊魚死於魚翅貿易,其中包括受到嚴重威脅的物種。」「消費者吃魚翅時不會知道牠們吃的是什麼,然而,他們可能吃了一個瀕危的物種。」

查普曼博士是紐約州立大學石溪分校海洋保護科學研究所副主任,他和芝加哥菲爾德博物館(Field Museum)的普利茲克實驗室(Pritzker Laboratory)合作,針對對湯樣本進行了分析;他們改良現有的DNA條碼技術(DNA-barcoding techniques),以辨識在處理和烹飪魚翅過程中受損的DNA片段。

除了路易氏雙髻鯊以外,研究小組發現有32個樣本確定為鯊魚,包括錘頭雙髻鯊(smooth hammerhead)、翅鯊(school shark)與白斑角鯊(spiny dogfish),牠們都屬國際自然保護聯盟紅色名錄中瀕危與易危的物種。

皮尤環境組織(Pew Environment Group)為該調查提供了資金上的協助,而組織中負責全球鯊魚保育的Liz Karan表示,「這進一步證明,不只在亞洲地區,魚翅湯在美國同樣會造成全球鯊魚數量減少。」

皮尤環境集團的鯊魚保育活動是一個全球性工作,致力於拯救鯊魚。自2009年活動開始以來,六個國家,如:帛琉、馬爾地夫、洪都拉斯、巴哈馬群島、托克勞群島(Tokelau)與馬紹爾群島,已創建國家鯊魚保護區,總面積達180萬平方英里。

Karan表示,「我們必須避免鯊魚遭到過度捕撈,且嚴格監控這些瀕危和易危物種的所有國際貿易行為。」

查普曼的研究結合DNA分析與生態數據,以更好地了解大型海洋脊椎動物,特別是鯊魚,的族群生物學、演化與生態習性。

除了路易氏雙髻鯊以外,其他在美國魚翅湯碗中發現的瀕危物種包括:屬於易危的錘頭雙髻鯊、尖吻鯖鯊(shortfin mako)、白斑角鯊與翅鯊,以及屬於近危的大青鯊(blue shark)、短尾真鯊(cooper shark)、低鰭真鯊(bull shark,又稱公牛鯊、公牛白眼鮫)。

哥斯大黎加和洪都拉斯於今年6月宣布,將於2013年3月舉行的華盛頓公約(Convention on International Trade in Endangered Species, CITES)會議上,提出關於雙髻鯊的的新貿易規定。

魚翅乃是由切下海上捕獲鯊魚之魚鰭所得,而尚未死亡的鯊魚將被丟回海中。受傷的鯊魚無法正常運動,終將窒息而死或被捕食者吃掉。

2005年六月,魚翅曝曬在香港的陽光下。(Alvin Loke 攝)IUCN鯊魚專家小組(Shark Specialist Group)表示,割鯊魚鰭(shark finning)的行為是普遍存在的,絕大多數都缺乏管理與監控,而迅速擴張且無管制的魚翅貿易即是全球鯊魚族群最嚴重的威脅之一。

鯊魚專家小組160位專家在其網站上的聯合聲明表示,「我們認為整個世界大洋與公海都應該有割鯊魚鰭的禁令。」他們警告,「割鰭行為使得成千上萬的鯊魚死亡,強烈威脅稀有與脆弱物種的生存。而大量海洋生態系頂級掠食者的消失,可能對生態造成有劇烈且不良的影響,並威脅到其他經濟物種的產量。」

魚翅是全世界最昂貴的海產之一,零售價通常為每公斤400美元。由於魚翅貿易的大多未有報告,因此全球魚翅貿易值只能粗略估計,約為5.4億至12億美元。研究估計,每年約有2600萬至7300萬隻鯊魚被捕獲並取下魚鰭。

魚翅在華人慶祝宴會上是常見的食物。美國禁止割鯊魚鰭,而一碗魚翅湯要價70至150美元。

 
Fins of Endangered Sharks Found in U.S. Soup Bowls
WASHINGTON, DC, August 14, 2012 (ENS)

Genetic testing of shark fin soup from cities across the United States found DNA from eight endangered and threatened shark species.

In the first nationwide analysis of shark fin soup, bowls of the Asian delicacy served in 13 out the 14 U.S. cities tested were found to contain species at risk of extinction.

A bowl of soup sampled in Boston contained fin meat of a scalloped hammerhead shark, which is listed as Endangered on the IUCN Red List of Threatened Species.

To arrive at their conclusions, scientists analyzed DNA from shark fin soup samples gathered in Albuquerque, Atlanta, Boston, Chicago, Denver, Fort Lauderdale, Houston, Las Vegas, Los Angeles, New York, Orlando, San Francisco, Seattle, and Washington, DC.

Denver was the only city where the soup samples did not contain fins from species listed as Endangered, Vulnerable or Near Threatened by the IUCN.

Shark attack survivors who have become global advocates for conservation of their attackers helped collect some of the samples for the study. The survivors, as well as the soup study, will be featured during Discovery’s show “Shark Fight” at 9 pm EDT Wednesday, August 15.

Dr. Demian Chapman, who co-led the research team, said, “The DNA testing again confirms that a wide variety of sharks are being killed for the fin trade, including seriously threatened species.”

“U.S. consumers of shark fin soup cannot be certain of what’s in their soup. They could be eating a species that is in serious trouble,” he said.

The soup samples were analyzed at the Institute for Ocean Conservation Science at Stony Brook University in New York, where Dr. Chapman is assistant science director.

Dr. Chapman worked with the Pritzker Laboratory at the Field Museum in Chicago to modify existing DNA-barcoding techniques to identify shark DNA fragments that had deteriorated in the fin treatment and cooking process.

In addition to the scalloped hammerhead, the research team found that the 32 samples identified as sharks included smooth hammerheads, school sharks, and spiny dogfish, which are all listed as Vulnerable to extinction on the IUCN Red List.

“This is further proof that shark fin soup here in the United States – not just in Asia – is contributing to the global decline of sharks,” said Liz Karan, manager of global shark conservation at the Pew Environment Group, which financially supported the research.

The Pew Environment Group’s shark conservation campaign is a worldwide effort focused on saving sharks. Since the start of the campaign in 2009, six countries have created national shark sanctuaries: Palau, the Maldives, Honduras, the Bahamas, Tokelau, and the Marshall Islands, covering a total of 1.8 million square miles.

Karan said, “Sharks must be protected from overfishing and any international trade in these vulnerable and endangered species must be tightly regulated.”

Dr. Chapman’s research combines DNA analysis with ecological data to better understand the population biology, evolution, and ecology of large marine vertebrates, particularly sharks.

In addition to the scalloped hammerhead, other at-risk shark species found in U.S. soup bowls include: the smooth hammerhead, the shortfin mako, the spiny dogfish, the school shark – all listed as Vulnerable to extinction; as well as the blue shark, the copper shark and the bull shark – all listed as Near Threatened.

In June, Costa Rica and Honduras announced plans to propose new trade rules for hammerhead sharks under the Convention on the International Trade in Endangered Species, which meets next in March 2013.

Shark fins are obtained by slicing the fins off of sharks caught at sea; the bodies of the living sharks often are thrown back. Unable to move normally, the damaged sharks die of suffocation or are eaten by predators.

The IUCN’s Shark Specialist Group says shark finning is widespread, “largely unmanaged and unmonitored” and that “the rapidly expanding and largely unregulated shark fin trade represents one of the most serious threats to shark populations worldwide.”

“We consider, therefore, that a ban on shark finning is justified throughout the world’s oceans and high seas,” the 160 experts of the Shark Specialist Group say in a joint statement on their website.

“Finning causes the death of tens of millions of sharks. This potentially threatens the survival of rare and vulnerable species and, by removing large numbers of top predators from the oceanic ecosystem, may have dramatic and undesirable ecological impacts that could potentially threaten yields of other commercial species,” warns the Shark Specialist Group.

Shark fins are among the most expensive seafood products anywhere in the world, commonly retailing at $400 per kilogram. Because the shark fin trade is largely unreported, estimates of the global value of the shark fin trade can only be rough, ranging from US$540 million to $1.2 billion. Studies estimate that between 26 to 73 million sharks are harvested annually for their fins.

Shark fin soup is popular as a banquet food at Chinese celebrations. In the United States, where shark finning is prohibited, a bowl of the gelatinous soup can cost between $70 and $150.

全文及圖片詳見:Environment News Service