They are just magnificent.

姥鯊是相當美妙的生物，真的非常不可思議

They grow 10 meters long; some say bigger.

牠們身長足足有10公尺

They might weigh up to two tons.

也有人說比10公尺長

Some say up to five tons.

體重達2噸

They're the second-largest fish in the world.

也有人認為將近5噸

They're also harmless plankton-feeding animals.

牠們是全世界第二大的魚類

And they are thought to be able to filter a cubic kilometer of water every hour

是以捕食浮游生物為主的無害動物

and can feed on 30 kilos of zoo plankton a day to survive.

據說每小時

They're fantastic creatures.

可以過濾1立方公里的海水

We're very lucky in Ireland,

每天攝食高達30公斤的浮游動物

we have plenty of basking sharks and plenty of opportunities to study them.

實在是太不可思議了

They were very important to coastal communities,

愛爾蘭有許多姥鯊

going back hundreds of years,

讓我們有幸能研究牠們

especially around the Claddaghduff, Connemara region

姥鯊對海洋生態社區也是相當重要的

where subsistence farmers used to sail out on their hookers and open boats,

早在幾百年前

sometimes way offshore to a place called the Sunfish Bank,

特別在克拉達、達夫和康尼瑪拉地區

about 30 miles west of Achill Island,

獨立農夫會出海

to kill the basking sharks.

乘著漁船

This is a woodcut from about the 1800s.

出海到一個叫太陽魚淺灘的地方

They were very important, for the oil out of their liver.

大概離愛奇島48公里以西的位置

A third of the basking shark's size is their liver,

去捕殺姥鯊

and it's full of oil, gallons of oil.

這是來自17, 18世紀的木版畫

That oil was used especially for lighting,

因為姥鯊肝臟含很多肝油，所以當時地位非凡

but also for dressing wounds and other things.

肝臟占身體的1/3，滿滿是油

In fact, the streetlights in 1742,

從牠們的肝臟就能提鍊出好幾加侖的肝油

of Galway, Dublin and Waterford,

這些油當時主要供照明用途

were lit with sunfish oil.

除此之外也可用來治療傷口等等

"Sunfish" is one of the words for basking sharks.

事實上，在1742年

So they were incredibly important animals.

戈爾韋、都柏林和沃特福的路燈

They've been around a long time, very important to coastal communities.

多多少少都跟太陽魚肝油有關

Probably the best-documented basking shark fishery in the world

姥鯊又叫「太陽魚」

is that from Achill Island.

所以牠們算是相當重要的動物

This is Keem Bay up in Achill Island.

歷史久遠，對海洋生態社區也非常重要

Sharks used to come into the bay,

擁有全世界最完整的姥鯊文獻紀錄的

and the fishermen would tie a net off the headland,

就是愛奇島

string it out, an old Manila net,

這是愛奇島的欽灣

and as the shark came round, it would hit the net,

以前鯊魚會在這裡出沒

the net would collapse on it.

漁夫就會把魚網掛在岬角上

It would often drown and suffocate.

再展開和其他魚網連接

Or at times, they would row out in their small curraghs

鯊魚來了一觸碰到魚網，網子就會掉下來

and kill it with a lance through the back of the neck.

鯊魚就會因窒息而溺死

And then they'd tow the sharks back to Purteen Harbour,

有時候還會划小船出去

boil them up, use the oil.

用魚叉往牠們背後戳

They also used the flesh as well, for fertilizer

最後在一路將屍體拖回波庭港口

and also would fin the sharks.

煮沸，再提練肝油

This is probably the biggest threat to sharks worldwide --

剩下來的肉也被用來當肥料

the finning of sharks.

當然也會採割魚翅

We're often frightened of sharks, thanks to "Jaws."

全球最大的鯊魚元兇

Maybe five or six people get killed by sharks every year.

就是採割魚翅這個行為了

There was someone recently, wasn't there? Just a couple weeks ago.

看過「大白鯊」這部電影的人都對鯊魚懷有恐懼之心

We kill about 100 million sharks a year.

每年大概有5-6人

So I don't know what the balance is,

死於鯊魚攻擊

but I think sharks have more right to be fearful of us than we have of them.

前陣子不是就有人遇害？才幾個禮拜前而已

It was a well-documented fishery.

但我們每年捕殺1億條鯊魚

As you can see here, it peaked in the '50s,

真曉得天理何在

where they were killing 1,500 sharks a year.

照理講，鯊魚應該要比較怕我們才對

And it declined very fast -- a classic boom-and-bust fishery,

這個獵捕行為紀錄完整

which suggests that a stock has been depleted

從這裡可以看到，在50年代達到高峰

or there's low reproductive rates.

每年獵殺高達1500條鯊魚

They killed about 12,000 sharks within this period,

接著急遽下降，這就是漁業大起大落的特性

literally just by stringing a Manila rope

這就顯示鯊魚的數量已所剩無幾

off the tip of Keem Bay up in Achill Island.

不然就是繁殖率非常低

Sharks were still killed up into the mid-80s,

在這期間將近12,000隻鯊魚遭殺害

especially out of places like Dunmore East in County Waterford.

光是愛奇島的欽灣

About two and a half, 3,000 sharks were killed up till '85,

用馬尼拉繩捕殺的數量

mainly by Norwegian vessels.

就這麼多了

You can't really see,

一直到80年代中期，獵鯊行為仍盛行

but these are Norwegian basking shark hunting vessels.

尤其是在沃特福的鄧莫爾東郡地區

The black line in the crow's nest signifies this is a shark vessel,

到1985年還是有2500到3000條鯊魚遭捕殺

rather than a whaling vessel.

其中有很多是挪威的漁船

The importance of basking sharks to the coast communities

圖中黑色的船，這裡有點看不清楚，是挪威獵捕姥鯊的船隻

is recognized through the language.

瞭望臺上的黑線

I don't pretend to [know many Irish words],

表明這是一艘獵捕鯊魚的船

but in Kerry they were often known as "ainmhide Na seolta,"

而不是捕鯨船

"the monster with the sails."

姥鯊在海洋生態社區占有的重要地位

Another title would be "liop an dá lapa,"

體現在語言上

"the unwieldy beast with two fins."

我不想假裝自己很懂愛爾蘭語

"Liabhán mór," suggesting a big animal.

不過在凱里郡，大家把姥鯊形容為「Ainmhide na seolta」

Or my favorite, "liabhán chor gréine," "the great fish of the sun."

意指「帶帆的怪物」

That's a lovely, evocative name.

還有另一個稱號是「Liop an da lapa」

On Tory Island -- a strange place anyway -- they were known as "muldoons."

意思是「龐大笨重的兩鰭怪」

(Laughter)

還有「Liabhan mor」，形容巨大的動物

No one seems to know why.

還有我最愛的別名「Liabhan chor greine」

Hope there's no one from Tory here. Lovely place.

也就是「偉大的太陽魚」

But more commonly all around the island, they were known as the sunfish.

還滿可愛又充滿聯想的名字

And this represents their habit of basking on the surface

托裏島上，反正那裡也滿奇怪的，姥鯊又叫「馬爾登」

when the sun is out.

沒有人知道為什麼

There's great concern that basking sharks are depleted

希望在座沒有來自托裏島的朋友，那裡很迷人

all throughout the world.

不過最常用的別名

Some say it's not population decline,

是太陽魚

it might be a change in the distribution of plankton.

這個名字最能代表牠們喜歡曬太陽的行為

It's been suggested

姥鯊在全球各地瀕臨絕種的現象

that these sharks would make fantastic indicators of climate change,

非常令人擔憂

as they're basically continuous plankton recorders,

有人認為這不是數量的減少

swimming around with their mouth open.

可能是浮游生物分布情況改變了

They're now listed as vulnerable under the IUCN.

也有人認為姥鯊數量的減少

There's movements in Europe to try and stop catching them.

是反映溫室效應的指標

There's now a ban on catching and even landing them,

因為牠們最能反映浮游生物的狀況

even landing ones caught accidentally.

成天嘴巴開開游來游去的

They're not protected in Ireland;

國際自然保護聯盟已將姥鯊列為「瀕危」狀態

in fact, they have no legislative status in Ireland whatsoever,

歐洲各國也正嘗試採取行動停止獵捕活動

despite our importance for the species

現在已立法禁止捕捉姥鯊，甚至禁止讓牠們上岸

and also the historical context within which basking sharks reside.

就連意外捕捉到的也不行

We know very little about them.

然而，愛爾蘭卻沒有保護姥鯊

And most of what we do know

事實上，愛爾蘭完全沒有相關禁止的法律條文

is based on their habit of coming to the surface --

儘管我們知道姥鯊有多重要

we try and guess what they're doing from their behavior on the surface.

以及牠們賴以生存的歷史意義

I only found out last year, at a conference on the Isle of Man,

我們對姥鯊的了解甚少

just how unusual it is to live somewhere

所了解最多的

where basking sharks regularly, frequently and predictably

也只能從牠們喜愛浮出水面的習慣下手

come to the surface to "bask."

然後試著揣測她們的行為

It's a fantastic opportunity for a scientist

從牠們在水面上的行為來猜測

to see and experience basking sharks.

我一直要到去年一場在曼島的會議中

They are awesome creatures.

才意識到，住在一個

It gives us a fantastic opportunity to study them, to get access to them.

姥鯊經常固定浮出水面來曬太陽的地方

What we've been doing for a couple years -- last year was a big year --

是多麼難得

is we started tagging sharks,

這對科學研究來說，能親眼看到姥鯊

so we could try to get some idea of sight fidelity and movement

實在是相當可貴

and things like that.

牠們真的是非常不可思議的生物

So we concentrated mainly in North Donegal and West Kerry

住在這裡，使我們可以實際研究、接近牠們

as the two areas where I was mainly active.

我們好幾年來在做的事--去年對我們來說滿重大的

And we tagged them very simply, not very high-tech,

我們開始標幟鯊魚

with a big, long pole.

這樣才能追蹤

This is a beachcaster rod with a tag on the end.

牠們的動態以及棲地忠實性

You go up in your boat and tag the shark.

我們主要集中在

And we were very effective.

登內加爾北部和凱里郡西部

We tagged 105 sharks last summer.

這兩個區塊我比較熟悉

We got 50 in three days off Inishowen Peninsula.

我們標識的方法非常簡單又有點土法煉鋼

Half the challenge to get access

是用一個又大又長的竿子

is to be in the right place at the right time.

這是一個beachcaster牌的竿子

But it's a very simple, easy technique; I'll show you what it looks like.

在尾端有標幟

We use a pole camera on the boat to actually film the shark.

就到船上標幟鯊魚

One, it's to try and work out the gender of the shark.

我們相當有效率

We also deployed some satellite tags, so we did use high-tech stuff as well.

去年夏天就標了105條鯊魚

These are archival tags.

三天內就在印尼豪恩半島

What they do is store the data.

標了50條鯊魚

A satellite tag only works when the air is clear of the water

主要是抓準時間，也要抓對地點

and can send a signal to the satellite.

不過這是一個非常簡單的技術

And sharks and fish are underwater most of the time,

來給大家看牠們的樣子

so this tag actually works out the locations of shark,

我們在船上使用竿子上的相機

depending on the timing and the setting of the sun,

來拍攝鯊魚

plus water temperature and depth.

首先要分辨鯊魚的性別

And you have to kind of reconstruct the path.

我們也用了一些衛星標，所以也有運用到高科技產品

What happens is,

這些是衛星檔案標幟

you set the tag to detach from the shark after a fixed period --

可以儲存資料

in this case, eight months --

衛星標只能在接觸空氣並沒有水的狀況下

and literally to the day, the tag popped off,

才能使用並發送訊號給衛星

drifted up, said hello to the satellite

當然，鯊魚和魚類大部份的時間都在水裡

and sent, not all the data, but enough data for us to use.

所以這個標幟會根據時間和太陽的升降

This is the only way to really work out their behavior and movements

來推斷鯊魚的位置

when they're underwater.

其中也會考量海水的溫度和深淺

And here's a couple of maps that we've done.

我們必須根據收集的資料重建路線

In that one, you can see that we tagged both off Kerry.

要設定讓標幟在一定的時間後自動脫落

Basically, it spent all its time, the last eight months, in Irish waters.

我們的設定是八個月

On Christmas, it was out on the shelf edge.

時間到了，標幟會浮出水面，傳資料給衛星

Here's one we haven't ground-truthed yet

而且並不是全部的資料，而是讓我們足以使用的資料

with sea-surface temperature and water depth,

這是唯一可以摸透

but again, the second shark spent most of its time

牠們在水裡行為的辦法

in and around the Irish Sea.

這邊是我們做的一些地圖

Colleagues from the Isle of Man last year actually tagged one shark

可以看到兩個都在凱里郡標幟到鯊魚

that went from the Isle of Man to Nova Scotia in about 90 days.

基本上牠在過去八個月都在愛爾蘭海域活動

Nine and a half thousand kilometers -- we never thought that happened.

聖誕節跑到棚緣

Another colleague in the States tagged about 20 sharks off Massachusetts.

這個我們還沒實地勘察

His tags didn't really work.

海面溫度及水深

All he knows is where he tagged them,

不過，第二隻鯊魚大部份時間

and where they popped off.

也在愛爾蘭海域活動

His tags popped off in the Caribbean,

去年有一位曼島的同事

and even in Brazil.

標到一隻鯊魚

We thought basking sharks were temperate animals

在90天以內從曼島跑到加拿大的新斯科舍省去

and lived in our latitudes,

距離有9500公里，相當驚人

but in actual fact, they're obviously crossing the equator as well.

還有另一個美國的同事

So very simple things like that,

在麻省標了大概20隻鯊魚，他的標幟有點故障

we're trying to learn about basking sharks.

只知道標幟的地點

One thing that I think is a very surprising and strange thing

和最後浮出來的位置

is just how low the genetic diversity of sharks is.

結果他的標幟竟出現在加勒比海

I'm not a geneticist, so I won't pretend to understand the genetics.

甚至在巴西

And that's why it's great to have collaboration.

我們以為姥鯊是溫帶動物

Whereas I'm a field person,

只能在我們這裡的緯度生存

I get panic attacks

不過事實上，牠們很明顯也會到赤道地區

if I have to spend too many hours in a lab with a white coat on.

所以我們就是企圖瞭解姥鯊的

Take me away.

這些簡單的事情

So we can work with geneticists who understand that.

我發現

So when they looked at the genetics of basking sharks,

有一件非常奇特的現象

they found that the diversity was incredibly low.

就是鯊魚的基因多樣性很低

If you look at the first line, really,

我不是基因學家，也沒有要假裝自己很懂基因學

you can see that all these different shark species are all quite similar.

這時候跟別人合作就很棒

I think this means they're all sharks

我擅長田野調查

and they've come from a common ancestry.

如果要我在實驗室待好幾小時

But if you look at nucleotide diversity,

我就會瘋掉

which is more genetics that are passed on through the parents,

這時候就可以和擅長這塊的基因學家合作

you see that basking sharks, if you look at the first study,

當他們觀察姥鯊的基因

was order of magnitude less diverse even than other shark species.

就發現基因多樣性極低

You can see this work was only done in 2006.

你看看第一條線

Before 2006, we had no idea of the genetic variability of basking sharks.

就可以看到這些不同種類的鯊魚長得滿相近的

We had no idea: Did they distinguish into different populations?

這大概就表示牠們都是鯊魚

Were there subpopulations?

且來自相同的祖先

And that's very important if you want to know

如果觀察核苷酸多樣性

what the population size is, and the status of the animals.

也就是由父母傳下來的基因

So, Les Noble in Aberdeen kind of found this a bit unbelievable, really.

會發現姥鯊，看第一份報告

So he did another study using microsatellites,

多樣性

which is much more expensive, much more time-consuming,

比其他鯊魚種類還低

and to his surprise, came up with almost identical results.

這份研究在2006年完成

So it does seem to be that basking sharks, for some reason,

在2006年之前，我們對姥鯊的基因多樣性毫無概念

have incredibly low diversity.

我們不知道牠們是否分散為不同的族群？

And it's thought maybe it was a genetic bottleneck,

那麼次族群又在哪裡？

thought to have been 12,000 years ago,

這是很重要的資訊

and this has caused a very low diversity.

也就是動物的族群及現況

And yet, if you look at the whale shark,

英國阿伯丁大學的諾柏

which is the other plankton-eating large shark,

覺得這相當不可思議

its diversity is much greater.

於是他做了另一項研究

So it doesn't really make sense at all.

並使用微衛星

They found that there was no genetic differentiation

微衛星更貴又更費時間

between any of the world's oceans of basking sharks:

最後結果卻幾乎一模一樣

even though they're found throughout the world,

所以看起來

you couldn't tell the difference, genetically,

姥鯊的基因多樣性確實極低

from one from the Pacific, Atlantic, New Zealand, Ireland, South Africa.

也許這是一個瓶頸，一個基因上的瓶頸

They all basically seem the same.

可能在12,000年前

Which, again, is kind of surprising; you wouldn't expect that.

造成了非常低的多樣性

I don't understand or pretend to understand this;

不過你看豆腐鯊

I suspect most geneticists don't either,

另一個以浮游生物為食的大型鯊魚

but they produce the numbers.

多樣性就高很多

So you can actually estimate the population size

這實在是沒道理

based on the diversity of the genetics.

他們發現在世界上的姥鯊

And Rus Hoelzel came up with an effective population size:

沒有基因上的差別

8,200 animals.

即使姥鯊分布在世界各地

That's it -- 8,000 animals in the world.

在基因上卻沒有差別