在中国台湾的澎湖列岛上，一群年轻人正致力于修复古老的石沪。位于中国台湾澎湖县七美乡的双心石沪
图片来源：Zeze0729, CC BY-SA 3.0, via Wikimedia Commons
杨馥慈今年 28 岁，来自中国台湾的澎湖列岛，世界上石沪最为密集的地区之一。她创办了一家名为“离岛出走”（Isle.Travel）的石沪主题旅行工作室，致力于保护、宣传和修复这些石沪。每年冬天是澎湖列岛捕鱼的季节，“离岛出走”会选择与当地社区居民合作，在夏秋季通过以工换宿的形式招募志愿者对石沪进行维护和修补，同时围绕石沪发展多种形式的观光旅游业务，到冬季，“沪主”即可出海巡沪捕鱼，杨馥慈和她的团队伙伴们还重建了当地废弃已久的鱼干厂，用传统的鱼灶加工捕获的小鱼。杨馥慈说，从海岸望向这些石沪时，她会产生一种超现实的感觉，历史仿佛正鲜活地呈现在眼前。这种简单而巧妙的古老渔业建筑，基于两个互相交织的理念之上：海洋可以养活我们，而我们也要保护好海洋。石沪在澎湖居民的生活中发挥着重要作用，它们不仅为当地家庭和寺庙提供生计，还彰显了渔民们的合作精神。石沪的存在也提醒我们，几千年来，人类一直努力与海洋建立一种可持续的关系。在深入了解石沪的悠久历史之前，我们首先须要知道石沪究竟是什么。石沪是一种利用潮汐的传统陷阱式渔法，属于鱼梁的一种，它的工作机制非常简单：选择一条海岸线，通常是潮间带或礁石滩，这些地方的潮汐比较强烈。然后你可以用任何你能找到的东西——石头、竹子或木头——在海里筑起一道道矮墙。你须要根据水流和鱼类游动的方向，用矮墙围出一个隔间，这个隔间的形状可以是一个平滑的圆，也可以是蘑菇状或尖箭头状，什么样的都有。在澎湖列岛，有一些石沪看起来就像巨大的心脏，两侧有长长的“动脉”延伸到远方，引导鱼类进入这个建筑的内室——沪房中。涨潮时，矮墙被海水淹没，鱼可以在石沪内外自由地穿梭。但是当潮水退去，许多鱼就会被困在石沪里，渔民可以从这个临时大鱼缸中捕获到他们所需的量，剩下的鱼则能在下一次涨潮时重获自由。澎湖列岛位于中国台湾和中国大陆之间的浅海峡，是由大约 90 个岛屿组成的集群，这里的渔民几个世纪以来一直在使用石沪捕鱼。时至今日，澎湖列岛周边海域仍保留了 600 多座石沪。1697 年，中国官员郁永河所著的《裨海纪游》描述了当时中国台湾的风土人情，其中就提到了当时澎湖列岛居民以石沪捕鱼的场景，表明石沪至少在 1697 年就已经存在。日记中还写道：“澳有大小，居民有众寡，然皆以海为田，以鱼为粮……”除了澎湖列岛，类似于石沪的鱼梁在日本、韩国甚至夏威夷群岛等地区也广泛存在。菲律宾大学迪利曼分校（University of the Philippines Diliman）的海洋人类学家辛西娅·内里·扎亚斯（Cynthia Neri Zayas）这些年来专注于研究中国台湾及整个亚太地区古代渔民的海上生活习俗，包括石沪的历史。辛西娅还研究了石沪的传承模式。以澎湖为例，渔村里的几大家族会共同拥有几座石沪，他们通常会象征性地去寺庙中结拜，达成协议，还会形成分工，分别承担捕鱼、修理和看守石沪等任务。建造石沪、维护石沪和用石沪捕鱼不是一个人单打独斗就可以完成的事，往往需要一个村庄分工协作，捕获的鱼也是村民共享的。充分发挥石沪的潜力同样也需要全村的共同努力。要想知道什么时候可以得到丰厚的鱼获，什么时候应该留出时间让海洋休息，就须要对潮汐、洋流的变化和鱼类习性有充分的了解。这种传统的生态知识在家族中代代相传，有时会以歌谣的形式流传下来，如中国海南岛的潮汐歌，它描述了与石沪捕鱼法有关的潮汐涨落规律，朗朗上口的歌词可以让人轻松记住潮汐涨落的时间节点。不是只有亚太地区的渔民会这样做。一些科学家认为，陷阱捕鱼技术可能比现代人类的历史还要久远。考古记录表明，在上一个冰河时代末期，人类已经会使用鱼梁来改变潮水的方向，使其对自己有利。在南极洲之外的各个大洲中都可以看到这类装置的身影。可以说，哪里有人类，哪里就会出现这样的捕鱼陷阱。造成这一现象最有可能的原因是，它们是人类真正建造出的第一批物理建筑之一，也是人类最早能掌握的最复杂结构之一。爱尔兰都柏林大学圣三一学院（Trinity College Dublin）的海洋考古学家保罗·蒙哥马利（Paul Montgomery）表示，欧洲最古老的鱼梁大约已有 9000 年的历史，是一座在瑞典海岸水下海床发现的木制鱼梁，研究人员使用放射性碳定年法（radiocarbon dating）和树轮年代学（dendrochronology）对它出现的时间进行了测定。2022 年，科学家又在美国阿拉斯加州海岸发现了一座更早的石制鱼梁，距今大约 11,000 年。考古学家可以使用放射性碳定年法分析有机物质所含放射性碳同位素的衰变，来辅助估测木制鱼梁出现的时间，而对于石沪，确定年份的工作就会变得很棘手。研究人员只能尝试确定在石沪附近发现的贝冢（史前时代，人们捕食贝类后贝壳堆积形成的遗址）的年代，分析沉积物和周围海岸线随时间的变化，甚至须要通过海平面重建模型来确定它的年代。一个地区的具体石沪数量是很难确定的，许多石沪因人类沿海的开发活动而被摧毁，有些则因弃用年久失修而分崩离析，考古学家须要寻找被掩埋的石沪遗迹。保罗花费了大量时间来编目可能存在石沪的位置，结合不同的地图平台或软件对其进行标记和定位，再去实地考察。理想状况下，如果能赶在退潮时抵达石沪，随着潮水的退去，就可以在不同的水位层次上观察一座石沪的轮廓和形状。这有助于人们了解它的运作机制，以及它在历史长河中的变化和演化。考古学家须要调查石沪的各种形状、使用的岩石类型和建造方法；还须要测试石沪的功能，评估进入其中的鱼类和其他海洋物种的数量和多样性。保罗的研究团队还对石沪进行了三维扫描，以制作计算机模型，并模拟过去的气候情景。这可以帮助研究人员评估不同类的石沪结构在不同历史时期可能的表现。除了研究不断变化的环境条件对石沪的影响外，科学家还研究了这些变化对渔民的影响。分析渔民在改用另一种石沪之前使用某类石沪的时间长短，可以帮助研究人员了解当气候变化导致鱼类种群变化时渔民们的适应策略。尽管石沪是人造的，但它逐渐融入了海洋生态系统，珊瑚、幼蟹、小鱼……无数海洋生物都以这些石沪为家，让这种捕鱼方法的可持续性大大延申。很多石沪都不会对鱼类赶尽杀绝，这与商业化捕鱼不同，在商业捕捞船上，上船的每条鱼要么走向死亡，要么被当做副渔获物被丢弃，石沪则可以让渔民在有收获的同时，不会对更广泛的海洋生态造成破坏。近年来已经有研究证明，石沪对其所在的海洋环境改善有积极的促进作用。以一些亚太地区的石沪为例，包括密克罗尼西亚联邦的雅浦岛或中国台湾的澎湖列岛，珊瑚已经在这些地区的石沪上生长，使其成为了珊瑚礁的一部分。它们变成了活……[查看全文]
Sustainable Fishing with Ancient Chambers and Ocean Tides
Fu-Tzu Yang: When I stand on the coast and look at stone fish weirs, it feels surreal. I can see living history in front of my eyes.
Kata Karáth: That’s Fu-Tzu Yang. She’s from China's Taiwan Penghu archipelago, home to one of the world’s highest concentrations of shi hu, or stone tidal fish weirs.Fu-Tzu, who is 28 years old, runs a local tourism agency called Isle.Travel. It’s dedicated to promoting, restoring and preserving these fish weirs. The simple but ingenious ancient fishing structures are built on two intertwining principles: the ocean can provide for us—but only if we all take care of the ocean.Yang: Stone tidal fish weirs play an important role in the lives of communities in Penghu because they not only provide a livelihood for local families and temples, but they also demonstrate the spirit of community collaboration.[CLIP: People work together to restore a fish weir]Karáth: Tidal fish weirs are living reminders that a sustainable relationship with the world’s oceans is something that humans have managed to achieve for thousands of years.Before we jump into the deep end of tidal fish weir history, let’s start with the obvious question: What are they?Karáth: Their mechanics are incredibly simple: You pick a shoreline—generally a tidal or reef flat—where the tides are strong. There you build walls out of whatever is available. That can be stone, like Fu-Tzu mentioned, but also other materials such as bamboo or wood. The walls form chambers sculpted into everything from plain curves to shapes resembling puffy mushrooms or pointy arrows, depending on currents and fish behavior.There are also tidal weirs, including some in Penghu, that look like giant hearts with long arteries stretching out into the distance, guiding and welcoming fish into the structures’ inner chambers.[CLIP: Waves crash and seagulls scream]Karáth: When the high tide comes, the walls are submerged, and the fish can swim within them freely. But when the tide ebbs, the creatures are trapped. Fishers can catch as much as they need from the temporary tanks. The rest will slip away come high tide.In the Penghu archipelago—a cluster of about 90 islands in the shallow strait between Taiwan and mainland China—fishers have been using this technology for centuries. More than 500 fish weirs remain in the waters there to this day.Cynthia Neri Zayas: I have material from my research in Penghu—it’s a translation of a Chinese official’s diary on his way to Taiwan in 1697, and this is an indication that the stone tidal weirs were already there in 1697. And I quote: “The sea is their field, and the fish is their crop.”Karáth: This is Cynthia Neri Zayas, a maritime anthropologist at the University of the Philippines Diliman.Zayas: And in Japan in 1724 the king of Okinawa ordered a fish weir to be built for his concubine in the island of Kohama with the use of sandofu: obligatory labor.Karáth: Cynthia studies the history of tidal weirs in Taiwan and other parts of the Asia-Pacific region. She’s also researched how weirs passed from generation to generation.Zayas: In the village, when you have something like Penghu, you know, extended families own several stone tidal weirs, and they’re usually united symbolically in a temple they go to. So the “X” family—comprising one, two, three, four, five households—worship in this temple, and the members of that divide the tasks of catching, repairing, guarding, etcetera, of the stone tidal weirs.Karáth: As both Fu-Tzu and Cynthia pointed out, fishing with a tidal weir takes a village. You simply cannot operate or maintain one of these structures alone. Tasks are divided up among many people—and, as Cynthia has written, so are the fish caught using the weir.Using a weir to its full potential is a community affair, too. Knowing when to expect plentiful catches—and when to give the sea time to rest—requires an understanding of tides, currents and of course, the fish. This traditional ecological knowledge is usually passed down through families, sometimes with the help of music, such as on the Chinese island of Hainan.Zayas: There are also tide songs—this I read in Hainan—which is passed from generation to generation. It describes the lows of tide related to the stone tidal weir, you see, so you remember when the tide comes, when it is the lowest, when it is the highest, you know? You remember easily because you’re singing.Karáth: And the fishers in the Asia-Pacific region were not alone. Some researchers believe it’s possible that fish-trapping technology predates modern humans. Regardless, the archaeological record shows that around the end of the last ice age, humans were using weirs to literally turn the tides to their advantage.Paul Montgomery: They have been found on every continent except Antarctica. Basically where humans go, fish traps occur. Why? Because most likely they are one of the first physical structures that humans actually built—one of the most complex going back into our deepest history.Karáth: That’s Paul Montgomery of Trinity College Dublin in Ireland. He’s a maritime archaeologist.Montgomery: In the case of Europe, the oldest one is probably about, maybe, 9,000 years old. It’s a wooden fish weir that was found off the coast of Sweden on a submerged seabed and has been dated using wood-based carbon dating and also dendrochronological dates. In a case last year—actually about a year and a half ago—there was a new discovery found off the coast of Alaska where they discovered a fish weir that was 11,000 years old.Karáth: As Paul says, archaeologists can use radiocarbon dating to help estimate the age of wooden fish weirs. To do so they analyze the decay of a radioactive carbon isotope contained in the organic material. When it comes to stone weirs, however, their job is much trickier. Researchers can try to date the shell middens found near the weir, analyze the sediments and the change of the shorelines around them over time or even determine their age based on sea-level reconstruction. It’s also hard to tell how many tidal fish weirs are out there. Many have been destroyed by coastal developments. Others fell apart after communities stopped using them. Archaeologists have to go looking for their buried remnants.Montgomery: I spend a huge amount of time cataloging locations of possible fish traps, mapping them with different platforms or software such as Google Maps to identify roughly where they are. Then you go out to the site. Ideally the best way to do it is to arrive there when the tide is dropping because then you can see the outline and the shape of the trap at different levels as the tide goes down. It’ll give you an idea of how it functioned and also is it changed or has it evolved?Karáth: Archaeologists carry out surveys of the various shapes weirs took as well as the types of rocks and construction methods used. Researchers test the weirs’ functionality, too, checking the amount and diversity of fish and other marine species that come through them.Paul says his research group also creates three-dimensional scans of weirs to make computer models and play out past climate scenarios. This allows the researchers to evaluate how the different types of structures potentially fared over time.Alongside studying the impacts of changing environmental conditions on the weirs, scientists also look at the effects these shifts had on the fishers. Analyzing the amount of time fishers used a certain type of weir before switching to a different kind can give researchers clues about how communities adapted to climate-induced changes in fish populations.And even though they are human-made, tidal weirs slowly become part of marine ecosystems, as a myriad of sea creatures—from corals to larval crabs and even young fish—call these structures home. That adds to the sustainability of this fishing method.Montgomery: Many of these structures are nonfatal ways of fishing. Unlike commercial fishing, where every fish—nearly—that comes onto the boat is either dead or cast back as bycatch, this form of fishing allows not only you to access these resources without damaging the wider marine ecology—actual fish weirs have been proved by scientific papers in the last several years to be actively encouraging the growth of marine environments within them.Karáth: As an example Paul points to fish weirs in the Asia-Pacific region, including the Micronesian island state of Yap or Taiwan’s Penghu archipelago.Montgomery: Corals have actually grown and started to grow on top of them, around them and become part of the reef. They are literally...[full transcript]
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