The one thing stopping jellyfish from taking over - Mariela Pajuelo & Javier Antonio Quinones

譯者: 麗玲 辛 審譯者: 穎君 紀

Over the past two decades, jellyfish have begun to overwhelm our oceans.

過去二十年來， 水母越來越多，充斥海洋。

In New Zealand, divers swat off millions of stinging jellyfish

在紐西蘭，潛水員要不斷拍掉 數以百萬計的刺人水母，

each no larger than a grain of pepper.

每個都不比一粒胡椒粒大。

In Sweden, a massive cluster of moon jellyfish

在瑞典，曾有一大群月亮水母

shut down one of the world’s largest nuclear reactors

堵塞了世界最大核反應爐的重要管道，

by clogging the plant’s essential pipes.

導致該反應爐關閉。

And in the Sea of Japan, thousands of 200 kilogram Nomura’s jellyfish

在日本海，數千隻重達兩百公斤、

with bells two meters in diameter swarm fishermen,

鐘狀體直徑達兩公尺的 野村水母群聚在漁民周圍，

snapping nets and devouring local fish.

撕裂網子，吞噬當地的魚類。

Around the world, these animals voraciously consume fish eggs and larvae,

在世界各地，這些生物 貪婪地吞食魚卵和幼魚，

routinely undermine marine farming efforts,

一次次破壞海洋養殖成果，

and outcompete adult fish by consuming the resources they need to survive.

並吃掉成魚所需的資源， 在物競天擇中擊敗魚群。

If things stay on their current trajectory,

如果事情這樣發展下去，

we could be headed for a future where the entire ocean is thick with jellyfish.

以後整片海洋可能厚厚一層都是水母。

So, is there anything that can keep these gelatinous creatures under control?

那麼，有什麼東西可以控制 這些凝膠狀生物呢？

Enter, the humble sea turtle.

讓我們介紹，不起眼的海龜。

There are a wide range of marine animals that feed on jellyfish,

許多海洋動物都會吃水母，

but sea turtles are among their most ancient predators.

但海龜是最古老的水母天敵。

And while every known species of sea turtle preys on jellyfish

雖然已知的每種海龜在一生中 都必定會捕食水母，

at some point in their lives,

none consume quite as many as the leatherback.

但沒有一種吃得跟革龜一樣多。

Leatherbacks are the largest species of sea turtle,

革龜是最大的海龜物種，

and they eat jellyfish almost exclusively,

牠們幾乎只吃水母，

devouring well over 1,000 metric tons of them over their roughly 50-year lifespans.

在大約 50 年壽命中 會吃一千多噸的水母。

This is particularly remarkable because jellyfish are 95% water

這數字很可觀，因為 水母 95% 是水，

and very low in calories,

熱量非常低，

so to maintain a healthy weight,

所以為了保持健康的體重，

the average 500 kilogram leatherback

平均 500 公斤的革龜

needs to eat roughly 400 kilograms of jellyfish every day.

每天需要吃約 400 公斤的水母，

That’s roughly the same weight as a grand piano.

相當一架大鋼琴的重量。

And while some sea turtle species have been documented

據記錄，一些海龜物種

selectively eating their preys’ protein-rich gonads,

只吃水母富含蛋白質的性腺，

leatherbacks eat jellyfish whole—

而革龜會吃整隻水母——

mowing down huge swaths of unsuspecting jellies.

横掃大片毫無戒心的水母。

Normally, jellyfish aren't quite this defenseless.

通常，水母不會這麼毫無防備。

Most species have tentacles covered in cells called cnidocytes,

大多數物種的觸手上都佈滿 稱為刺絲胞的細胞，

which contain venomous harpoons coiled and ready to launch.

內含帶毒鉤刺，隨時準備發射。

These barbed structures, known as nematocysts,

這些帶刺的結構被稱為刺絲囊，

are released on contact.

在接觸時射出。

Jellyfish frequently use this sting to paralyze and kill their food,

水母經常用這些刺來麻痺和殺死獵物，

and it can also irritate the skin of would-be intruders.

也會刺痛不速之客的皮膚。

But it's completely useless against sea turtles.

但這對海龜們完全沒用。

Most of these reptiles have thick scales covered in keratin—

這些爬行動物多數有厚厚的鱗片， 上面覆蓋著角蛋白——

the same material that makes up nails and claws.

與構成指甲和爪子一樣的材質。

This leathery armor protects their skin while they hunt,

這種皮質盔甲在捕獵時 保護牠們的皮膚，

and any captured prey that tries to escape is impaled

任何捕獲的獵物，如果試圖逃跑，

on the keratinized spikes lining the leatherback’s esophagus.

都會被革龜食道內的角質皮刺刺穿。

For most sea turtles, these adaptations make individual jellyfish easy prey.

對大多海龜來說，這些演化適應 讓捕食單隻水母易如反掌。

However, a jelly population’s true defense mechanism

然而，水母群體真正的防禦機制

is in how quickly they can reproduce.

在於牠們的繁殖速度。

Almost all jellyfish species have evolved to reproduce both sexually and asexually,

幾乎所有水母物種 都已進化成可有性及無性繁殖，

allowing them to increase their numbers with or without a partner.

無論有沒有伴侶， 牠們的數量都可以增加。

In tropical environments,

在熱帶環境中，

jellyfish reproduce constantly throughout the year.

水母全年不斷繁殖。

But in more temperate climates,

但在溫帶氣候地區，

species often reproduce all at once in a massive bloom,

物種常常會一次性大量繁殖，

where jellies multiply at alarming rates.

水母繁殖的速度更是驚人。

And humanity is making these blooms much more frequent.

而人類使大量繁殖次數變得更加頻繁。

Fertilizer runoff from farms introduces chemicals

農場的化肥廢水逕流 把化學物質帶進海裡，

that simultaneously kill other fish and prompt blooms.

殺死其他魚類， 同時引發水母大量繁殖。

High water temperatures caused by climate change

氣候變遷造成的高水溫

speed up jellyfish reproduction and extend the reproductive season.

加速水母的繁殖，延長繁殖季節。

Meanwhile, both marine construction and pollution

與此同時，海洋建設和垃圾的表面

dramatically increase the surface area for jellyfish polyps

帶來大量水母螅體附著、 生長和成熟所需的表面積。

to attach, grow, and mature.

All these issues require a wide range of policy-based solutions.

這些問題需要許多政策打底的解決方案。

But one major way to prevent jellyfish populations from getting out of hand

但防止水母數量失控的一個主要方法

is to protect their natural predators—

是保護水母的天敵——

many of whom are currently under threat.

許多天敵目前正受到威脅。

Small-scale fisheries that are essential to communities in Mexico and Peru

墨西哥和秘魯當地主要的小規模漁業

often use gillnets,

常使用刺網，

which unintentionally capture and kill hundreds of sea turtles each year.

每年無意中捕獲並殺死數百隻海龜。

In the Eastern Pacific, these practices could drive leatherbacks to extinction

在東太平洋，這種漁法可能會導致 革龜在未來 60 年內滅絕。

in the next 60 years.

Fortunately, some researchers have already developed inexpensive tools

幸運的是，研究人員 已經開發出廉價的工具，

to minimize these risks.

可大大降低這些風險。

Attaching green LED lights to gillnets has proven useful

研究證明，在刺網上安裝綠色 LED 燈

for allowing sea turtles, dolphins, and even seabirds to avoid fishing gear.

可有效幫助海龜、海豚、 甚至海鳥避開漁具。

Solutions like this should allow small-scale fishers

像這樣的解決方案應該就能 讓小規模漁民養活他們的社區，

to support their communities

while minimizing their impact on our leathery ocean defenders.

同時盡量避免衝擊到堅韌的 海洋捍衛動物：海龜。