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就像它的食草同名一样，生活在的“叶羊”以海洋吃草为食。然而，它以一种独特的方式补充其饮食：通过太阳的力量。
Much like its herbivorous namesake, the ocean-dwelling "leaf sheep" grazes for food; however, it supplements its diet in a unique way: through the power of the sun.
“我第一次在朗布隆隆（菲律宾）看到小羊恩时，可爱的于它肖之小，”狂热的胡潜水员和海洋海洋者阿拉安说。“第二次在[内格罗斯东方省] 的道因（Dauin）更令人兴奋——我看到了五只抓到的叶子上，好像它们在一圈海藻上吃草。”
"The first time I saw Shaun the Sheep in Romblon [in the Philippines], I was surprised by how tiny it was," said Ara Juan, an avid diver and ocean advocate. "The second time in Dauin, [in the province of] Negros Oriental, was more exciting – I saw five of them perched on a leaf, so it looked like they were grazing on a field of algae."
人们被羊迷住了
People are captivated by the leaf sheep
“小羊肖恩”是菲律宾许多潜水员亲切地称其为一种奇怪的海洋生物，被称为叶羊（Costasiella kuroshimae），因为它与动画羊羔相似。与其名字所暗示的相反，叶羊既不是叶也不是羊——它是一种海蛞蝓。
"Shaun the Sheep" is what many divers in the Philippines affectionately call a curious sea creature known as the leaf sheep (Costasiella kuroshimae) due to its similarity to the animated lamb. Contrary to what its name suggests, the leaf sheep is neither leaf nor sheep – it's a sea slug.
“它们是娇嫩的生物，它们的身体就像没有壳的蜗牛，”潜水员兼摄影师吉纳维芙·雷耶斯 (Genevieve Reyes) 说。一种藻类，在他们自己的小世界里吃草。”
"They're delicate creatures and their bodies are like shell-less snails," said Genevieve Reyes, a diver and photographer. "Leaf sheep don't hide or retract when they feel your presence. They have a routine life, circling the leaf of an algae and grazing about in their own little world."
这种海洋无脊椎动物的黑色珠状眼睛紧靠在一起，白色的头部伸出类似羊耳或昆虫触角的黑色尖端的犀牛，身体上表面伸出点状绿色的角。海蛞蝓的 cerata 是类似于芦荟植物或斑马肉质植物的叶状附属物，但通常具有粉红色、紫色或白色的尖端，它们包含消化腺的分支。同时，犀牛在水中接收化学信号，赋予海蛞蝓嗅觉并使其能够找到食物来源。
This marine invertebrate has black beady eyes situated close together, rhinophores with black tips resembling sheep's ears or insect antennae sticking out of its white head and dotted green cerata popping out of the upper surface of its body. The sea slug's cerata are leaflike appendages akin to an aloe vera plant or a zebra succulent but typically with pink, purple or white tips, and they contain branches of digestive gland. Meanwhile, rhinophores pick up chemical signals in the water, giving the sea slug its sense of smell and enabling it to find food sources.
“人们被叶羊迷住了，因为它有一张可爱的脸和一个有趣的形状，”加州科学院无脊椎动物动物学和地质学高级策展人、海蛞蝓专家特伦斯·戈斯利纳 (Terrence Gosliner) 说，他的大部分研究都集中在在菲律宾发现的无数物种。“它们只是很棒的小蛞蝓。”
"People are captivated by the leaf sheep because it has a cute face and an interesting shape," said Terrence Gosliner, senior curator of invertebrate zoology and geology at the California Academy of Sciences and a sea slug expert who has focused most of his research on the myriad species found in the Philippines. "They're just great little slugs."
它们很小，成年后最长可长到七八毫米，寿命在六个月到一年之间。根据 Gosliner 的说法，叶羊是雌雄同体（具有雄性和雌性生殖器官），必须与另一个个体交配才能产生卵块。“卵孵化成带壳的幼虫，在浮游生物中度过一两个星期。然后，它们丢弃壳，开始作为小蛞蝓生活，”他说。
And little they are, growing to a maximum length of seven or eight millimetres upon adulthood and living between six months and a year. According to Gosliner, leaf sheep are hermaphrodites (having both male and female reproductive organs) and must mate with another individual to produce an egg mass. "The eggs hatch into shelled larvae that spend a week or two in the plankton. Then, they discard their shells and begin their life as a small slug," he said.
进行光合作用
Performing photosynthesis
叶羊生活在Avrainvillea 上，这是一种毛茸茸的毡状藻类，生长在软质基质（如淤泥或细沙）的地区。“它们不是在珊瑚礁中发现的，而是在珊瑚礁附近的区域中发现的，”Gosliner 说。 “在一片藻类叶片上可以看到多达 15 或 20 个。有时，你可以看到海蛞蝓的卵块，它们是微小的螺旋线圈。”
Leaf sheep live on Avrainvillea, a fuzzy, felty type of algae growing in areas with soft substrates, such as silt or fine sand. "They're not found in coral reefs but in areas next to coral reefs," Gosliner said. "The leaf sheep spends its whole life on that species of algae, and you can often see a whole colony of them there – I've seen up to 15 or 20 on one blade of alga. Sometimes, you can see the egg mass of the slug, which are tiny spiral coils."
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叶羊的卵团被塑造成微小的螺旋线圈（图片来源：Nature Picture Library/Alamy）
Avrainvillea 不仅是海蛞蝓的家，也是它的营养来源。作为 Sacoglossa 或“吸液”海蛞蝓的一种，叶羊在藻类上吃草（很像它的草食性同名），吸食其叶绿体（藻类细胞内含有叶绿素，一种绿色光合色素的结构）并保持它们在其cerata 的组织中长达10 天，这个过程称为kleptoplasty。这样做可以让叶羊通过光合作用补充其饮食，而光合作用通常仅由植物进行。这种光合作用能力为叶羊赢得了“太阳能海蛞蝓”的称号。
The Avrainvillea is not only the sea slug's home, but also its source of nourishment. As a species of Sacoglossa, or "sap-sucking" sea slug, the leaf sheep grazes (much like its herbivorous namesake) on the algae, sucks its chloroplasts (structures within the algae’s cells that contain chlorophyll, a green photosynthetic pigment) and keeps them within the tissues of its cerata for up to 10 days, a process called kleptoplasty. Doing so allows the leaf sheep to supplement its diet through photosynthesis, which is generally known to be performed only by plants. This photosynthetic ability has earned the leaf sheep its title of "solar-powered sea slug".
“这是少数能够做到这一点的多细胞生物之一，”菲律宾八打雁州立大学助理教授兼该大学佛得角岛通道海洋研究和水生科学中心 ( VIP CORALS )负责人米格尔·阿兹库纳 (Miguel Azcuna ) 说。“想象一下，你吃了一份沙拉，将叶绿体保留在你的消化系统中，所以你只需要把自己放在阳光下做食物。这对生存很方便。”
"It's one of the few multicellular organisms that can do it," said Miguel Azcuna, assistant professor at Batangas State University in the Philippines and head of the university's Verde Island Passage Center for Oceanographic Research and Aquatic Sciences (VIP CORALS). "Imagine you ate a salad and kept the chloroplast from it in your digestive system, so you just need to put yourself under the sun to make food. It's convenient for survival."
此外，藻类叶绿体为叶羊提供保护，赋予其绿色的伪装和化学防御，以阻止捕食者。
Moreover, algal chloroplasts provide protection for leaf sheep, giving it a green colour for camouflage and chemical defences to deter predators.
环境威胁
Environmental threats
叶羊并未处于严重危险之中，但它们仍然面临生存威胁，包括栖息地丧失。非法捕鱼和破坏性捕鱼（例如使用炸药或氰化物）等做法会破坏海洋栖息地并杀死生活在其中的动物。虽然这些做法在菲律宾已被取缔，但非法捕鱼和破坏性捕鱼在该国仍然存在。
Leaf sheep are not in critical danger, but they still face threats to survival, including habitat loss. Practices such as illegal fishing and destructive fishing (using dynamite or cyanide, for instance) destroy marine habitats and kill the animals living in them. While these practices have been outlawed in the Philippines, illegal fishing and destructive fishing still persist in the country.
叶羊广泛分布于亚洲，包括菲律宾（图片来源：Matt277/Getty Images）
气候变化也正在影响海蛞蝓的栖息地。全球变暖带来的更强烈的风暴和台风——菲律宾平均每年有 20 次——可能会破坏海洋区域，强大的海浪和洋流会产生沙尘旋风，可能会使叶羊脱臼并连根拔起它们生活的藻类。更酸性的海洋也可以改变动物的行为，正如对其表亲海兔的研究所证明的那样，当暴露于模拟的海洋酸化和变暖时，海兔的觅食成功率较低，并且做出的决定也更差。
Climate change, too, is impacting the sea slug's habitat. More intense storms and typhoons – the Philippines gets an average of 20 each year – brought about by a warming world could damage marine areas, with strong waves and currents creating whirlwinds of sand that could dislocate leaf sheep and uproot the algae they live in. Warmer and more acidic oceans could also alter the animal's behaviour, as demonstrated in a study on its cousin, the sea hare, which had less foraging success and made poorer decisions when exposed to simulated ocean acidification and warming.
塑料污染对该物种构成了另一个风险。“有时，作为我潜水的一部分，我最终会在水下捡垃圾，”胡安说。
Plastic pollution poses another risk to the species. "Sometimes, as part of my dive, I'll end up picking trash underwater," Juan said.
菲律宾 190 万吨管理不善的塑料垃圾中有三分之一以上最终流入海洋，使该国成为全球海洋塑料垃圾的第三大贡献者。摄入微塑料可能会阻塞叶羊的嘴或在其消化道中积聚，渗出的化学物质可能对其健康有害。
More than a third of the Philippines' 1.9 million metric tons of mismanaged plastic waste ends up in the ocean, making the nation the third-largest contributor to global marine plastic debris. Ingesting microplastics could obstruct a leaf sheep's mouth or accumulate in its digestive tract, and the chemicals leaching out could be harmful to its health.
为了应对其海洋环境日益严重的威胁，菲律宾已将某些栖息地指定为海洋保护区(MPA)。例如，八打雁的马里卡班岛于 2019 年被宣布为海洋保护区，限制了捕鱼活动，并让社区参与监测珊瑚礁健康并保持海岸线无垃圾。
To combat the growing threats to its marine environments, the Philippines has designated certain habitats as marine protected areas (MPAs). Maricaban Island in Batangas, for instance, was declared an MPA in 2019, limiting fishing activity and involving the community in monitoring reef health and keeping the shoreline trash-free.
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叶羊生活在 Avrainvillea 上，这是一种毛茸茸的毛毡藻类（图片来源：RibeirodosSantos/Getty Images）
以社区为基础的渔业和环境执法举措也已到位。这包括“ Bantay Dagat ”，全国各地的志愿者充当海洋的守护者，为非法捕鱼活动巡逻。
Community-based fisheries and environmental law enforcement initiatives are also in place. This includes "Bantay Dagat", wherein volunteers across the country serve as guardians of the sea, patrolling it for illegal fishing activities.
菲律宾各地的非政府组织也在提供帮助。VIP CORALS 的 Azcuna 团队与SEA Institute（Gosliner 担任主任）合作，在海边举办生态营地，教育生活在八打雁附近沿海社区的学生了解海洋生态系统的重要性。许多潜水度假村和运营商还定期进行海滩和潜水地点的清理工作，以收集岸上和水下的垃圾和其他塑料垃圾。
Non-government organisations across the Philippines are helping too. Azcuna's team at VIP CORALS partnered with the SEA Institute (where Gosliner serves as a director) to conduct eco camps by the sea, educating students living in coastal communities around Batangas about the importance of marine ecosystems. Many dive resorts and operators also conduct regular beach and dive site clean-ups to collect rubbish and other plastic waste on the shore and underwater.
潜水看叶羊
Diving to see leaf sheep
叶羊于 1993 年在日本黑岛首次被发现，但它也广泛分布在亚洲，在新加坡、泰国和珊瑚三角区都有目击事件，珊瑚三角区被认为是世界海洋生物多样性的中心，包括印度尼西亚水域，马来西亚、菲律宾、巴布亚新几内亚、所罗门群岛和东帝汶。
The leaf sheep was first discovered in 1993 in the Japanese island of Kuroshima, but it's also widely distributed across Asia, with sightings in Singapore, Thailand and the Coral Triangle, an area regarded as the world's epicentre of marine biodiversity encompassing the waters of Indonesia, Malaysia, the Philippines, Papua New Guinea, the Solomon Islands and Timor-Leste.
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与当地潜水向导一起探索时，潜水员可以更轻松地看到叶羊（图片来源：MikaelEriksson/Getting Images）
在菲律宾水域，在该国北部、中部和南部地区都发现了叶羊——从吕宋地区八打雁省阿尼洛珊瑚覆盖的裂缝到东内格罗斯省道因的淤泥底部。米沙鄢地区和棉兰老岛地区甘米银岛省的火山状斜坡和珊瑚礁。最佳游览时间是 12 月至次年 5 月，此时海水平静且台风季节已经结束。您可以乘坐称为bangka的支腿船到达大多数潜水地点，但一些潜水胜地在它们前面有一个“屋礁”。
Within Philippine waters, leaf sheep have been found in the country's northern, central and southern regions – from the coral-covered crevices of Anilao in the Batangas province of the Luzon region to the muck-filled bottoms of Dauin in the Negros Oriental province of the Visayas region and the volcano-like slopes and reefs of the island province of Camiguin in the Mindanao region. The best time to visit is during the months of December to May when waters are calm and the typhoon season has ended. You can reach most dive sites by riding an outrigger boat called a bangka, but some dive resorts have a "house reef" in front of them.
你只是他们家的访客，所以请尊重海洋环境
You're just a visitor to their home, so respect the marine environment
由于叶羊进行光合作用，因此可以在阳光仍然可以穿透的海洋下方 9 到 18m 之间找到它们。然而，海蛞蝓可能很难找到，因为它们很小。胡安说：“如果你有一个观察员——一位知道在特定潜水地点可以找到他们的当地潜水向导，那会很有帮助。”
Because leaf sheep undergo photosynthesis, they can be found between nine and 18m beneath the ocean where sunlight can still penetrate. Yet the sea slugs might be difficult to find owing to their minute size. "It would help if you have a spotter with you – a local dive guide who knows where to find them in a specific dive site," Juan said.
为了确保负责任的潜水，胡安的建议是练习适当的浮力，以避免撞击任何珊瑚或生物并破坏栖息地，因为您必须靠近叶羊才能看到它们。潜水时您也可能会遇到垃圾，因此请尽可能捡起并确保在潜水后妥善处理。不接触或移除植物和动物也很重要。
To ensure responsible diving, Juan's advice is to practice proper buoyancy to avoid hitting any corals or creatures and disrupting the habitat, as you'll have to get close up to the leaf sheep in order to see them. You might also encounter rubbish when diving, so pick up what you can and make sure to dispose of it properly after your dive. Not touching or removing plants and animals is also crucial.
潜水员亲切地称叶羊为“小羊肖恩”（图片来源：Westend61 GmbH/Alamy）