離奇 鯨鯊擱淺亡

蘋果日報 20091029

達人語：
海生館前館長、正修科技大學講座教授方力行表示，鯨鯊在馬尼拉灣擱淺死亡是罕見情況。雖然鯨豚擱淺死亡時有所聞，但鯨鯊很少如此，研判可能是生病或受到驚嚇，才會擱淺死亡。
方力行說，鯨鯊是鯊不是鯨，牠是體型最大的魚類，最大可達8公尺、12公噸重，是變溫性動物。因肉嫩質細，又被稱為「豆腐鯊」，過去常被捕殺食用，導至數量銳減，目前已列保育類動物。方力行說，鯨鯊對人友善，他曾與鯨鯊在海中共游過，目前澳洲有相關旅遊行程，可讓遊客近距離觀察鯨鯊。文╱陳威廷˙圖╱法新社、路透


鯨鯊小檔案

菲律賓海巡隊員用繩索綑綁鯨鯊，打算將牠運送到實驗室了解死因。
學名：Rhincodon typus
體型：最大可達8公尺長、12公噸重
分布：全球中緯度以下海域皆可見
特徵：深灰帶點藍色的表皮、身上有白斜條紋與白星點、嘴中有骨板，骨板上分布凹凸不平的細齒
資料來源：方力行

註：新聞中有誤，鯨鯊可達18公尺。

---

Dead 'butanding' found in Manila Bay

By Anna Valmero
INQUIRER.net
First Posted 19:25:00 10/28/2009

MANILA, Philippines— A whale shark, locally called “butanding”, was found dead on Manila Bay by local fishermen on Wednesday morning, according to the local arm of conservationist group World Wide Fund for Nature (WWF).

WWF Philippines information officer Gregg Yan said the possible causes for the butanding’s death include disease, gear entanglement, exposure to organic pollutants and ship strikes.

Measuring 15-feet long, the female whale shark bore a few scars, including small cuts on its tail possibly caused by a rope and strange injuries to both eyes, with the eyeballs missing when the carcass was found along the South Harbor at 1:30a.m., said Yan.

Earlier on Wednesday, the Philippine Coast Guard, Bureau of Fisheries and Aquatic Resources (BFAR), Department of Environment and Natural Resources (DENR), Manila Ocean Park and WWF went to the site where the dead whale shark was found to document the carcass.

A necropsy will be conducted to examine its cause of death, while the carcass will be immediately buried in the town of Dagupan in Pangasinan province, where the remains of other large sea creatures are buried.

The whale shark is the third largest marine animal to have died in Manila Bay over the past three years, said Yan. The first two include a dead baleen whale found floating beside a passenger ship moored in Manila Bay on December 2008 and another baleen whale carcass was found floating on August 2007.

Whale sharks can grow up to 40 feet long, with a maw wide enough to swallow a person. However, they feed only on planktons, acting as living filters to improve overall water quality in the seas.

Classified as a vulnerable species or close to being endangered by the International Union for Conservation of Nature in 2000, the global population of whale sharks continues to decrease, said Yan.

---

14-foot whale shark found dead in Manila Bay, to be buried in Pangasinan
By Evelyn Macairan (The Philippine Star) Updated October 29, 2009 12:00 AM
MANILA, Philippines - As people troop to cemeteries to honor their dead kin this weekend, officials of the Bureau of Fisheries and Aquatic Resources (BFAR) will visit a graveyard in Pangasinan to bury a two-year-old whale shark.

Philippine Coast Guard (PCG) commandant Admiral Wilfredo Tamayo yesterday said that the whale shark, locally called butanding, was found floating in Manila Bay by fishermen.

The whale shark (Rhincodon typus) is believed to be only two years old. The average life span of whale sharks is between 10 to 20 years.

Fishermen Melchor Cariño, Benzar Jara and Sadat Jara were on board the M/B Romar when they spotted the creature some 50 miles off the Manila Yacht Club at around 4 a.m. yesterday. At first, they thought it was just a large log floating on the water. They pulled it to the breakwater and called the media and authorities when they found out that it was a butanding.

Tamayo dispatched a rubber boat to tow the 5.2-meter whale shark to their headquarters. “But the whale shark was too heavy for them that they had to call for a second boat for assistance,” he said.

Upon reaching the PCG’s wharf, Tamayo instructed 15 of their draftees to pull the animal to the wharf, but they were no match for the two-ton fish. The PCG tried utilizing the crane from their Marine Environment Protection Command truck, but since its maximum capacity is only one ton, they were apprehensive that the crane would break if they persisted on pulling in the giant fish.

Tamayo instructed the crew of the rubber boat to bring the whale shark to a vessel with a bigger crane docked nearby. Once lifted from the waters, the whale shark would be turned over to BFAR for examination and disposal.

Edwin Alesna, BFAR-Fisheries Quarantine Regulation and Wildlife chief, said they would conduct a necropsy on the whale shark to determine the cause of death.

“We need to examine its belly to know what it ate. The Manila Bay is a polluted area and the pollutant might be a contributing factor,” Alesna said.

Tamayo hinted at the possibility that climate change could have caused the giant fish’s death.

Alesna, however, said that they are still exploring the possibilities. A quick check showed that the whale shark did not bear any serious injury and had only bruises that might have been sustained while it was being dragged.

It was also possible that the whale shark was already feeling ill and decided to stay close to shore.

The Manila Bay area is also teeming with plankton, the whale shark’s food, and the creature may have only wanted to feed.

“They go where the food is,” Alesna said.

The butanding are tropical fishes that are considered endangered species and are often found in Donsol, Sorsogon and in Pamilacan, Bohol. World Wildlife Fund (WWF) information, education and communication officer Gregory Paul Yan said they have so far tracked 280 whale sharks in Donsol.

But there were signs that its migratory patterns are changing. The BFAR official said there were sightings in Atimonan in Quezon province and in Batangas.

“These whale sharks come in groups called pods. So there is a possibility that there would be more sightings of whale sharks in Manila Bay,” he added.

---

Read more...

成功捕獲一尾大白鯊

重約1800 Kg，長約5.33公尺，母鯊。
相簿

Read more...

200公斤鯊魚宴

2009年10月19日蘋果日報

中國廣西南寧目前正在舉行東南亞國際美食節，有商家推出「鯊魚宴」，由燒烤師傅現場宰殺並進行燒烤，每串約新台幣48元，吸引許多食客嘗鮮。據了解，這次美食節共準備了6條虎鯊，每條身長約2公尺、重達200多公斤，都是從大連東海打撈。

中新社

Read more...

越濁越歡樂 - 淡水魟所激揚起的塵土會吸引四種慈鯛靠近尾隨

文獻來源: Garrone-Neto D, Sazima I. 2009. The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays. Neotropical Ichthyology, 7(3):499-501. [全文下載]

Abstract
One hunting tactic of freshwater rays (Potamotrygonidae), termed “undulate the disc and stir substrate”, is here reported to attract cichlids at two sites in the upper Paraná River. The ray species involved in such association are Potamotrygon falkneri and P. motoro, whose activity attract four cichlid species, namely Crenicichla britskii, Satanoperca pappaterra, Cichla kelberi, and Geophagus proximus, the two latter non-native species to the study area. The cichlids approach a ray when it begins to stir the substrate and form sediment clouds, and remain close to the ray during this activity only. The association is here regarded as following behavior even if very transient.

引用自：奇獸飼育學

Read more...

潛6米深 巧遇鯨鯊

2009年09月29日蘋果日報
一批潛水客本月25日到蘭嶼著名景點八代灣，欣賞沉船四周生長的五顏六色珊瑚，隨後在距離水面6公尺處等待安全減壓時，一尾身長7公尺的鯨鯊竟從眼前游過，鯨鯊身上還吸附一隻「搭便車」撿食的印魚 。有19年潛水經驗的帶隊教練賈立宇說，溫馴的鯨鯊「看起來像草食性大恐龍」。至於鯨鯊腹部的傷痕，海洋大學漁業科學系助理教授莊守正說，可能曾被捕獲又被釋放或碰觸海底礁石留下。文╱劉人瑋．圖╱台灣高技潛水提供

鯨鯊小檔案
學名：Rhincodon typus
俗稱：豆腐鯊
外型：呈圓柱狀，頭扁平口寬。體色為灰褐色至藍褐色，體側散布白色斑點及橫紋。為世界最大魚類，身長可達20公尺。
資料來源：中央研究院生物多樣性研究中心

Read more...

鯊魚的掠食伎倆--科學人

掠食性鯊魚廣泛分佈於各大洋中，位居食物鏈頂端，牠們尋找遠方獵物或進行近距離攻擊時，會靈活運用不同的感覺器官將獵物嘴到擒來。

文／楊嘉慧
審稿／台灣海洋大學環境生物與漁業科學系副教授　莊守正；中研院細胞與個體生物學研究所研究員　嚴宏洋


　鯊魚的攝食方式可分為腐食性、濾食性與掠食性，而張著血盆大口攻擊獵物的掠食性鯊魚，多屬於「白眼鮫科」（或稱真鯊科）及「鼠鯊科」種類，牠們廣泛分佈在各大洋中，搜尋獵物範圍從水表層至數百公尺深海、熱帶水域至極區等地都有可能。

靈活運用感覺器官

　鯊魚的掠食過程會運用不同感覺器官，遠距離時靠聽覺與嗅覺發現獵物的方位。中研院細胞與個體生物學研究所研究員嚴宏洋表示，鯊魚能接收的音頻範圍約只有100~1000Hz，不過卻能聽見數百公尺外傳來的微弱聲音（其微弱程度只能在水下傳播，空氣中則無法傳這麼遠）。鯊魚的嗅葉細胞也很發達，可偵側出濃度0.1ppb（1ppb為10億分之一）的血腥味，換句話說，1公克的血溶解於1萬公噸的海水中鯊魚都能察覺，這意味著鯊魚可經由嗅覺功能，在遠距離外察覺獵物的存在。

　鯊魚循著聽覺或嗅覺的線索接近獵物後，會改用視覺與側線感官進一步搜尋獵物的確實位置。鯊魚的視力可達200多公尺遠，眼睛裡有一層會反光的光神經纖維層（tapetum lucidum），可將穿透視網膜但卻沒被感應到的光，反射後再通過視網膜一次，增加感應機會，強化夜視能力。鯊魚身體左右兩側也和魚類一樣，各有一條側線，能偵側周遭水壓差異以及水流速度，從而判斷身旁獵物的狀況，以採取必要行動。鯊魚還可以依靠前吻的電覺偵測器偵測微弱電場，以精確判定獵物位置。據研究，獵物受到驚嚇、受傷後，會發出與其他海洋動物不同的電場，因此藉由電覺偵測器，鯊魚能輕易在混濁的海水或一群海洋動物裡，找到牠鎖定的獵物。（詳見《科學人》2007年9月號〈鯊魚的第六感〉）。

鯊魚追捕獵物過程：（1）遠距離可利用嗅覺和聽覺判定獵物方向；（2）靠近獵物時，改用視覺與側線；（3）攻擊前一刻，主要利用電感覺準確定位。（影像來源：《科學人》2007年9月號）
不容忽視的搏鬥武器

　台灣海洋大學環境生物與漁業科學系副教授莊守正表示，除了善用各種感覺器官，鯊魚近身攻擊時，也仰賴往內倒勾的尖牙與攻擊技巧。鯊魚終其一生都會換牙，前排牙齒若斷裂、磨損，後排牙齒便會遞補上去。因此鯊魚的嘴裡都是尖牙，一旦咬到獵物，會使獵物產生嚴重撕裂傷；第一波攻擊成功後，鯊魚會放走獵物，並在四周巡迴、觀察，待獵物失血過多、體力變差後，再進行第二次攻擊。莊守正認為，鯊魚的口部與眼睛的位置十分靠近，若咬住猛烈掙扎的獵物不放，自己的眼睛很容易受傷，這麼做可以保護自己。

圖為長臂灰鯖鮫皮膚表面的盾鱗，每片寬約200微米。由於盾鱗排列整齊，具有導流效果，可增強軸向流的穩定性、減小亂流產生，因而整體阻力下降。（影像來源：莊守正）

　此外，游速也是鯊魚的先天優勢。台灣大學機械工程學系教授楊鏡堂表示，鯊魚的皮膚表面佈滿盾鱗，每片盾鱗都有整齊的波浪狀凹槽。這些凹槽具有導流效果，可降低橫向亂流的產生、減小阻力（見右圖）；再加上紡錘狀的體形，讓鯊魚可以在極短時間內加速到時速30~50公里，能夠與之匹敵的海洋動物大概只有鮪魚及旗魚等中表層的洄游性魚類了。

鯊魚會攻擊人類？

　掠食性鯊魚以其他魚類和受傷、生病或已經死亡的海洋哺乳類動物為主食，為何有時會傳出牠們攻擊人類的消息？莊守正指出，鯊魚有近500種，有危險性的鯊魚只有30餘種。這類鯊魚大多生活在中、表層海域，其中有幾種鯊魚，例如大白鯊、虎鯊、牛鯊等會靠近海岸，與人類的活動範圍重疊，因此確有可能發生攻擊人類的事件，像2008年11月，屏東鵝鑾鼻驚傳漁船翻覆、船長遭鯊魚咬死意外即是一例。然而，九成以上的鯊魚攻擊人類事件應是「誤會」，例如人趴在衝浪板上雙腳踢水時，鯊魚可能誤以為是海豹、海獅，而衝上去攻擊，一旦發現味道不對就會游走；但有些大白鯊、虎鯊等可接受人類的味道，就可能持續攻擊。不過，人類遇上鯊魚並非死路一條，尤其是當牠們已經飽食一餐時，就不會有掠食行為；反倒是人類獵捕鯊魚的數量已遠遠超過鯊魚攻擊人類事件了。

濾食性鯨鯊

　除了牙尖嘴利、形象兇猛的掠食性鯊魚，鯊魚家族中也有濾食性的溫和派。例如今年3月疑似迷航游入台南運河的鯨鯊（又名豆腐鯊），便是以浮游生物為主食的濾食性鯊魚，牠沒有尖銳的牙齒，而是利用口裂吸取海水，經鰓耙過濾海水當中的生物來進食。

　鯨鯊是鯊魚中體型最大的，牠們濾食的目標卻是微小的浮游生物，浮游生物能供給的養份不多，因此鯨鯊還會吃當季的小型魚或幼魚。台灣海洋大學環境生物與漁業科學系副教授莊守正指出，曾有研究人員在鯨鯊的胃內發現小鮪魚、鯖魚等聚群性魚類，牠們會在某個特定時節出現在鯨鯊的生活範圍，當鯨鯊大口吸水時，這些小魚會連同浮游生物一起進入鯨鯊嘴裡。

　鯨鯊屬中表層棲息魚類，偶爾伴隨有深潛的行為，活動範圍在亞熱帶與熱帶之間。莊守正指出，鯨鯊有洄游行為，他曾利用人造衛星追蹤器追蹤鯨鯊，發現牠們會從台灣東岸（東經121度）往東洄游至東經136度以東水域，而國外學者也發現東太平洋墨西哥灣水域（約西經90度）的鯨鯊可往西洄游至東經150度以西；比對其洄游路徑與海洋浮游生物的消長，發現二者有關，由此推論，鯨鯊應屬東西向的攝食洄游，而非南北向的渡冬洄游。

　鯨鯊除了做水平方向的攝食洄游，也會隨著浮游生物的上下活動做垂直洄游。據觀測發現，鯨鯊在各水層的洄游時間，秋冬之間並無顯著差異，春夏時則會在表層水域停留較長的時間。這可能也與食物的多寡有關，因為春夏時表層食物較多，而秋冬海況差，海水混合較均勻，食物垂直分佈無顯著差異。不過，目前研究的觀測時間都相當短暫，鯨鯊的洄游行為是否真如上述推測，還必須蒐集更多資料，才能下明確結論。（詳見《科學人》2007年9月號〈謎樣鯨鯊〉

Read more...

全球首設鯊魚禁捕區

2009-09-26

【明報專訊】南太平洋島國帕勞（Palau）宣布，將在境內海域設立全球首個鯊魚保護區，禁止捕獵鯊魚。

帕勞總統托里比翁（Johnson Toribiong）會在周五的聯合國大會上，宣布這項決定，該國將約60萬平方公里的水域劃為禁捕區，相當於法國的面積，除禁止捕鯊外，亦嚴禁割下鯊魚鰭的行徑。帕勞水域有約130種瀕危鯊魚品種，包括巨雙髻鯊、豹紋鯊和遠洋白鰭鯊等。

不過只有2萬名國民的帕勞，只有一艘巡邏艇，估計執行禁令時會有一定困難。事實上，最近一項調查便發現，帕勞水域同時至少有70艘漁船在當地捕魚，其中很多是非法捕魚的。

托里比翁承認執行有困難，但他希望能拋磚引玉，引發其他國家仿效推行類似的保護鯊魚計劃。現時全球每年有多達1億條鯊魚被捕殺。

英國廣播公司/美聯社

---

Palau pioneers 'shark sanctuary'
By Richard Black-Environment correspondent, BBC News website

Palau is to create the world's first "shark sanctuary", banning all commercial shark fishing in its waters.

The President of the tiny Pacific republic, Johnson Toribiong, announced the sanctuary during Friday's session of the UN General Assembly.

With half of the world's oceanic sharks at risk of extinction, conservationists regard the move as "game-changing".

It will protect about 600,000 sq km (230,000 sq miles) of ocean, an area about the size of France.

President Toribiong also called for a global ban on shark-finning, the practice of removing the fins at sea.

"The need to protect the sharks outweighs the need to enjoy a bowl of soup"
President Johnson Toribiong

Fins are a lucrative commodity on the international market where they are bought for use in shark fin soup.

As many as 100 million sharks are killed each year around the world.

"These creatures are being slaughtered and are perhaps at the brink of extinction unless we take positive action to protect them," said President Toribiong.

"Their physical beauty and strength, in my opinion, reflects the health of the oceans; they stand out," he told BBC News from UN headquarters in New York.

The president also called for an end to bottom-trawling, a fishing method that can destroy valuable seafloor ecosystems such as coral reefs.

Local benefits

A number of developed nations have implemented catch limits and restrictions on shark finning.
Some developing countries such as The Maldives have also taken measures to protect the creatures; but Palau's initiative takes things to a new level, according to conservationists close to the project.

"Palau has recognised how important sharks are to healthy marine environments," said Matt Rand, director of global shark conservation at the Pew Environment Group.

"And they've decided to do what no other nation has done and declare their entire Exclusive Economic Zone a shark sanctuary.

"They are leading the world in shark conservation."

Mr Rand said that about 130 threatened species of shark frequented waters close to Palau and would be likely to gain from the initiative.

Although the country has only 20,000 inhabitants, its territory encompasses 200 scattered islands, which means that its territorial waters are much bigger than many nations a thousand times more populous.

Economics is clearly an incentive for the Palau government, which derives most of its income from tourism.

Sharks are themselves a big attraction for scuba-divers, and may also play a role in keeping coral reef ecosystems healthy.

Oceanic Whitetips and Scalloped Hammerheads will be safe in Palau's shark sanctuary. Footage courtesy of Living Ocean Productions

Globally, 21% of shark species whose extinction risk has been assessed fall into the "threatened" categories, and 18% are "near threatened". For a further 35%, there is not enough data to decide.

Over half of the species that spend most of their time in the upper layers of the ocean, exposed to fishing, are on the threatened list.

Illegal shark-finning is the main cause; but there are legal targeted hunts for fins and meat, and sharks are also caught accidentally on longlines set for fish such as marlin and tuna.

Port side catches

Enforcing the ban will be an issue for Palau, which possesses just one patrol boat capable of monitoring its waters.

A recent aerial survey found fishing 70 vessels in the area, most of them illegally.

But Carl-Gustaf Lundin, who heads the marine programme at the International Union for the Conservation of Nature (IUCN), said there were other ways of tackling the illegal trade.

"The time for setting aside tiny areas of sea that only protect a few sedentary species is over"
Carl-Gustaf Lundin, IUCN

"For example, the US has been sharing lists of illegal vessels with established fishing companies, so that they can report on their dishonest or non-decent peers," he said.

"We're also exploring what options there are for monitoring remotely at low cost.

"And you don't need to catch people out there in the ocean; everyone needs to land their fish, so as long as you have most nations signed up to oppose illegal fishing, your chances of catching them are pretty decent."

Dr Lundin noted that earlier this week, another Pacific island state, Kiribati, signed off a collaboration with the US that establishes the largest marine reserve on the planet.

"The time for setting aside tiny areas of sea that only protect a few sedentary species is over; and it (the Palau sanctuary) is important because it shows the way in terms of putting large areas aside."

Considered position

In organisations such as the International Whaling Commission and the Convention on International Trade in Endangered Species (CITES), Palau has in recent years regularly sided with pro-hunting countries such as Japan.

Mr Toribiong told BBC News that before going to New York for the UN General Assembly, he had planned to "state to the world that Palau will revisit its current position" on whaling.

But following the recent change of government in Japan, and because of the two countries' "close relationship", he said there would now be a bilateral meeting.

"My position is to reconsider our current position in light of the most recent scientific data to ensure that the current position that Palau takes will not lead to the depletion and extinction of whales," he said.

But when it came to sharks, the president said he was sure that the sanctuary is backed by science - sharks are threatened as a group of species, and sanctuaries can help.

"Not all nations consider shark fins as delicacies," he said.

"And we feel that the need to protect the sharks outweighs the need to enjoy a bowl of soup."
Asked what he would be urging other leaders to do, he said simply: "To follow suit."

Richard.Black-INTERNET@bbc.co.uk

Read more...