The big-beaked, rock-munching fish that protect coral reefs - Mike Gil

譯者: Lilian Chiu 審譯者: Helen Chang

As the sun rises over a quiet coral reef, one animal breaks the morning silence.

隨著太陽升起到 安靜的珊瑚礁上方，

一隻動物打破了早晨的寧靜。

Named for their vibrant scales and beak-like teeth,

這些鸚哥魚的名字來自牠們 顏色鮮明的鱗片及像鳥喙般的牙齒，

these parrotfish are devouring a particularly crunchy breakfast: rocks.

牠們正在狼吞虎嚥地吃 一種特別酥脆的早餐：

石頭。

It may not be immediately clear why any creature would take bites

或許無法馬上理解為什麼

有任何生物會想要去啃食海底。

out of the seafloor.

But the diet of these flashy foragers actually plays a key role

但這些俗豔的搶食者 其實扮演了一個關鍵角色：

in defending the coral reef’s complex ecosystem.

保衛珊瑚礁的複雜生態系統。

Massive coral reefs begin with tiny coral larvae,

大型珊瑚礁一開始 也只是小型的珊瑚幼蟲，

which settle on the seafloor’s hard surfaces

幼蟲住在海底的堅硬表面上，

and metamorphasize into coral polyps.

變態成為珊瑚蟲。

Over time, these polyps generate rock-like skeletons

隨時間，這些珊瑚蟲 會產生像岩石一樣的骨骼，

made of calcium carbonate.

骨骼由碳酸鈣構成。

Together, colonies of polyps produce large three-dimensional structures,

成群的珊瑚蟲一起製造出 大型的立體結構，

which form the basis of an underwater metropolis.

成為水中都市的基礎。

These coral complexes are full of nooks and crannies

這些珊瑚構成的結構中 滿是隱蔽處和裂縫，

that house and protect countless life forms.

成為無數生命形式的住處和庇護。

Even though coral reefs occupy less than one percent of the ocean floor,

雖然珊瑚礁只佔據 不到 1% 的海底面積，

these dense ecosystems are home to more than twenty-five percent of marine life.

有超過 25% 的海洋生命

以這些稠密的生態系統為家。

Many fish use corals as shelters for sleeping and to hide from large predators

許多魚類用珊瑚當作 庇護所，可以在裡面睡覺，

也可以在搜尋海草的過程中 到此躲避捕食性動物。

between their trips foraging for seaweed.

As the primary food source for many of the reef’s fish and invertebrates,

海草是許多珊瑚礁魚類 及無脊椎動物的主要食物來源，

seaweed is vital to this ecosystem.

對於這個生態系統極其重要。

But in high densities, seaweed can become problematic,

但若密度過高， 海草有可能帶來麻煩，

and even lethal to corals.

甚至會造成珊瑚死亡。

Seaweed grows on the same hard open surfaces that coral larvae rely on,

海草就生長在珊瑚幼蟲 所仰賴的堅硬開放表面上，

and their growth prevents new coral from settling and expanding.

海草的生長會阻撓 新的珊瑚定居、拓展。

These competitors have also evolved a variety of ways to kill existing corals,

這些競爭者也演化出多種 可以殺死既有珊瑚的方式，

including smothering and abrasion.

包括造成窒息以及磨損。

Some seaweed species even engage in chemical warfare—

有些種類的海草 甚至會打化學戰——

synthesizing compounds that destroy coral on contact.

合成一些化合物來摧毀 它們接觸到的珊瑚。

This is where parrotfish come in.

此時就該鸚哥魚登場了。

Like many reef fish, these colorful creatures eat seaweed.

和許多珊瑚礁魚類一樣， 這些多彩的生物也吃海草維生。

But unlike their neighbors,

但和牠們的鄰居不同，

parrotfish can completely remove even the tiniest scraps of seaweed

鸚哥魚能夠將海草從海底除去，

乾淨到一點都不剩。

from the ocean floor.

Their so-called beak is actually a mosaic of tightly-packed teeth

牠們所謂的喙，其實是 緊緊鑲嵌在一起的牙齒，

which can scrape and grind rock,

能夠刮落、磨碎岩石，

allowing them to consume every bit of seaweed covering a stony surface.

讓牠們可以將覆蓋在石頭 表面上的所有海草都吃光。

This helps parrotfish reach seaweed other fish can’t consume,

這個特點讓鸚哥魚能夠吃到 其他魚類無法吃到的海草，

while simultaneously clearing out open space for new corals

同時，還能為新珊瑚 清理出開放空間，

讓新珊瑚定居，讓既有珊瑚拓展。

to settle and existing colonies to expand.

Eating rocks is just one way parrotfish help manage seaweed.

吃岩石只是鸚哥魚 協助整理海草的方式之一。

Through a dynamic system of social networks,

透過社交網路的動態系統，

parrotfish can convey information to other coral dwelling fish.

鸚哥魚可以傳遞資訊給 其他住在珊瑚中的魚類。

Each fish’s presence and simple routine behaviors produce sensory information

每條魚的出現及簡單的例行行為 都會產生出感官資訊，

that nearby fish can see, hear, or smell.

鄰近的魚類可以 看見、聽見，或聞到。

They can even detect changes in water pressure produced by their neighbors

牠們甚至可以用 一種特殊的感覺器官

來偵測鄰居造成的水壓改變。

using a special sensory organ.

All these factors can inform the behavior of nearby fish.

所有這些因素，都能傳遞 鄰近魚類的行為資訊。

For example, a fish safely entering an open feeding ground

比如，一條魚安全地 進入了開放的攝食場，

and not getting attacked means it’s safe to forage.

且沒有遭受攻擊，就表示 可以安心在那裡覓食。

Conversely, a fish rapidly leaving a location can provide an early warning

相反的，一條魚快速離開某個地點，

就是一種預先警示， 表示有威脅迫近。

that a threat is approaching.

By simply trying to stay alive,

這些珊瑚礁魚類只是 單純地試圖活下去，

these reef fish can incidentally help their neighbors survive—

無意間也協助了 牠們的鄰居求生存——

and more of these fish means less seaweed.

而這些魚類越多，就表示海草越少。

Unfortunately, human activities over the last several decades

不幸的是，在過去 數十年間的人類活動

have disrupted almost every part of this complex system.

幾乎把這個複雜系統的 每個部分都破壞了。

In many coral reefs, overfishing has reduced the number of parrotfish,

在許多珊瑚礁地區，過度捕撈 已經造成鸚哥魚數量減少，

as well as other seaweed eaters, such as surgeonfish and rabbitfish.

其他吃海草的生物如刺尾鯛魚 及籃子魚也同樣不斷減少。

This has led to unchecked seaweed growth,

這個現象導致海草 可以無法無天地生長，

which threatens to degrade entire coral reefs.

因而產生讓整個 珊瑚礁劣化的威脅。

The parrotfish that remain live in much smaller communities.

剩下的鸚哥魚生活在 小很多的群落中。

Their reduced numbers can weaken their social network,

牠們的數量減少，會導致 牠們的社交網路變弱，

making surviving fish more timid and less effective at controlling seaweed.

讓存活下來的魚類更膽怯， 且無法有效控制海草。

Today, climate change and pollution are lowering coral’s natural defenses

現今，氣候變遷和污染都造成 珊瑚的天然防禦能力下降，

while contributing to runaway seaweed growth—

同時讓海草的生長遙遙領先——

leaving reef ecosystems more fragile than ever.

造成珊瑚礁生態系統 比以往都更脆弱。

Our reefs are vitally important to both marine and human life.

珊瑚礁對於海洋生命 及人類生命都極其重要。

Their unparalleled biodiversity offers unique opportunities for ecotourism,

它們無比的生物多樣性，提供了 獨特的機會，可以做生態旅遊、

sustainable fishing, and scientific research,

永續捕魚，以及科學研究，

while their rocky structures guard coastlines from waves and storm surges.

同時它們的岩石結構能保衞 海岸線，對抗海浪和暴潮。

Fortunately, continued research into reef species

幸運的是，持續研究珊瑚礁物種，

like the quirky and critical parrotfish can inform new strategies

比如多變又重要的鸚哥魚，

提供的資訊可以用來制訂策略， 以保存這些重要的生態系統。

for preserving these essential ecosystems.