1993 / 7月
Chang Chin-ju /photos courtesy of courtesy of Liu Hung-chang /tr. by Jonathan Barnard
While man has caused a steady loss of coastal land and has numerous development plans in the works for the shorelines, along the coast of Hsinchu a young scholar has been taking one step at a time in his research on coastal ecologies.
Many people see the benefits of developing the Hsiangshan coastline with industrial and residential zones. But he sees something else.
When the tide is receding in Haishanchuan Ao, a small bay near the Hsiangshan coast of Hsinchu, people leave deep impressions of their footprints on the soft and level sands--but only after little creatures have already left a myriad of their marks.Creatures on the edge:
With the peaceful sound of distant waves, this stretch of land seems so featureless and tranquil. It is in fact teeming with life, full of colorful small crabs. With red and yellow bodies, fiddler crabs vanish back into their holes when sound or movement announces the approach of other creatures. Ghost crabs put their feet on the edge of their holes to stake out their realms. Known as "sea monks" in Chinese, soldier crabs, which look like pearls, recklessly rush out of their small holes in the sand, flickering silver-blue under the sun.
For the past two years, Liu Hung-chang, a graduate student at National Tsing Hua University has come to this piece of land rarely visited by people to record some 30 kinds of crab. Among these are silver-colored soldier crabs, whose numbers are greatest. When the tide is out, they band together into dozens--even hundreds--of groups. Here for hours at a time, Liu sometimes feels as if they are ambushing him on all sides.
But these "crab armies" may be marching on their last campaigns.
"When I was in National Chunghsing University, in the mountains near Taichung along the Tsaohu River, I conducted investigations on river crabs. In the mountain streams, there are numerous shrimps and crabs. I could record more than five hundred river crabs a night. Ponds would be full of the light emitted from shrimps' eyes. It was beautiful, like the Milky Way. But now the Water Conservancy Bureau is planning to build a dam on the Tsaohu River, preparing it to be used as Taichung's future source of drinking water. In the future, as the river ecologies change, it will be hard to predict how this will affect the river shrimps and crabs," Liu explains. "Then when I enrolled in the doctoral program at National Tsing Hua University, I came to Hsiangshan to perform research on eulittoral zone crab species, and now there is a plan to make new land from the sea with land fill. The targets of my research are like the natural environment equivalents of people on the edge; their space is easily disturbed by the tentacles of development."Crabs by the seashore:
The tidal land at Hsiangshan is one of a string of areas that have recently been targeted for development by the government. In all, the provincial government hopes to wrest some 1000 hectares of land from the sea.
But the eulittoral zone, a 500 to 2000 meter strip along the seashore, is the area with the most Taiwan fiddler crabs, a species unique to Taiwan. According to research carried out by National Taiwan Ocean University and Liu Huang-chang, many species of crab were spread widely throughout Western Taiwan's tidal flats, but as the shores have been eroded and the beaches polluted, the once abundant seashore creatures have been rapidly declining. Among such rivers in central Taiwan as the Lukang, Tatu and Houlung, the Lukang has almost no eulittoral zone left. Because of a newly built thermal power station, the mouth of the Tatu river has been severely damaged. If you want to find groups of fiddler crabs and soldier crabs, whose numbers are the largest of all, you'll have to go to Hsiangshan.
At the beginning of this year, a Korean expert in shoreline animals came to Taiwan to do research. Staff of the Taiwan Provincial Museum brought him all over the province to carry out research. In other places the animals living in the sand were few and far in between, but when he got to the coast by Hsin- chu, he happily found abundant shoreline wildlife.Resolving the secrets of life:
Crabs originated from the ocean but many have evolved and now live on the eulittoral zone where the land and sea meet. Because man also evolved from out of the sea, our interest in sand crabs and their physical and biochemical adaptability stems from an interest in ourselves. And so there is a lot of research being conducted around the world on land crabs.
Studying at the Life Sciences Research Center of National Tsing Hua University, Liu's interest in crabs extends beyond a search for the secrets of man's development. When he was in college, he had already become greatly interested in animal behavior. He climbed mountains and delved into the sea with researchers of fish and plants and selected crabs as his own long-term target for observation.
When others come to this coast, it may seem dreary and desolate. But for Liu Hung-chang and crabs, it holds an abundance of treasures.
There are different kinds of sand in the eulittoral zones: sand that easily absorbs water, fine sand, sticky sand, etc. Crab species have clear preferences. "Soldier crabs live in relatively wet sandy areas, and fiddler crabs dig their holes in relatively dryer mud, whereas ghost crabs live above the high tide line," says Liu Hung-chang, as if he is listing his family treasures.The "rounded" sea monks:
In the eyes of Liu Hung-chang, each crab species is special. They all differ in behavior and appearance. Ghost crabs whisk along quick of foot. Male fiddler crabs have one small claw and one large one, giving them unusual proportions. In their movement and behavior, soldier crabs simply don't look like crabs. Rather than scurrying everywhere sideways, they move straight. "Not all crabs move sideways," says Liu, a long-time observer of crabs. "And not all of them have sharp double claws and a large mouth."
Liu conjectures that among the crabs of the seashore, soldier crabs were perhaps one of the earliest to leave the sea for the land. The earliest to get on dry land, their gills have changed, taking on some of the functions of lungs and allowing them to breathe on land. Their round shape has allowed for the expansion of the gill chambers; in this they differ markedly from the flat bodies of other crabs.
From April to June, clumps that look like small round chimneys appear on the sands. "This means that the baby soldier crabs have come on land," Liu explains. Because their eggs are bigger, a young river crab can develop entirely within the egg. For crabs in tidal zones, the young must return to the sea to live. After they shed their shells several times, they return to land where they dig holes to live in. They pile the excavated sand outside, and the result looks like small chimneys. A young crab develops into an adult in a year.
"But the age of a crab is more of a mystery than the age of a woman," Liu says. Crabs shed their shells every several months, and they thoroughly change their entire bodies, "completely making themselves over." Even their organs, such as the inside wall of their stomachs and intestines, are completely remade. And hence it is hard to tell the age of a crab by looking at its body. "We are ignorant about a lot of crab behavior."Making a last stand with the crabs:
But how much more time does Liu have to try to under stand the crabs of Taiwan? According local government plans, in addition to such facilities as the Hsinchu airport, the shore will be the site of a tourist area that can hold 3 million visitors. Because the government estimates that the population will approach 1 million after Hsinchu County and City are merged, in the blueprints for development of residential areas, sewage treatment plants and garbage dumps have all been planned for the coast.
What effect would the landfill project have on the sand crabs? "Without the beach, the sea water won't be able to come up, and they will lack nutrients, food and water. How can the sand crabs, which need to go to the tide line to get their gills wet when the tide is rising, live on?" says Liu, feeling that the loss is as much his as the crabs. He is even more worried that after this land is developed, it will become like Nanliao, Hsinchu's only operating seaside amusement park, "covered with litter, its water yellow and dirty, its air full of thick smoke!"
Hsinchu is at the narrowest point of the Taiwan Strait. Because of topographical reasons, it is the windiest spot in all of Taiwan. In the winter, there are often sand storms along the coast. Once the county government began building a residential development on the mountain slopes, but the wind was so strong it couldn't be completed. In the winter, people simply can't stand the northeast winds. Liu, who has carried out detailed research on estimating the environmental effects of the industrial area, is baffled and says, "Who would be willing to live here?" While the profits to be made by building along the coast are few, the site is well suited to be an ecological classroom.The world in one grain of sand:
Specializing in crab ecologies, Liu, whose skin has been tanned a deep brown, says people may feel that this place left in its natural state would be unproductive, unable to help the county raise money. "But little kids feel that crabs are extremely cute." Many Hsinchu elementary schools come here for their ecological studies programs. Liu is the best ecological teacher. "If you bring kids here to look at crabs, when you want to leave, you can shout all you want, but you won't be able to get the kids to line up."
But crabs are more than just fun. Because of a high salt content, few species are suitable for living in eulittoral zones. But because there are many organisms being washed out of the river mouths, the food is plentiful, and the populations of the species that do exist here are always large. This is especially the case for the countless number of small crabs. When they return to the sea, most of them become a major source of food for marine life.
The crabs in eulittoral zones are an important base-level consumer in the food chain. They play an important role in the ecological system. They break down pollutants, turning them into inorganic substances, which flow out with the tide to become food for algae, which become food for fish, which in turn end up on our dinner tables.
At the hearing for the landfill development plans at Hsiangshan, Liu did, of course, do his best to beg for mercy for the crabs, explaining the meaning they hold for people. But he knows it's beyond his power to get people to leave behind this chunk of natural coastline for the next generation to decide how to use.Paradise by the sea:
"In the future, I'll go to some uninhabited island to do my research," he says. A lot of land crabs live on such islands. On Christmas Island off Australia, for instance, there is a colony of more than 100 million crabs of one species. Every year, during their migration, the sight is magnificent. "On an uninhabited island, I would be the crabs' one and only enemy."
Liu, though understanding crabs best, would make a pushover of a predator.
At the end of this year along the Hsiangshan Coast of Hsinchu, landfill will be used to create 1000 hectares of new land. If the tidal areas are lost, so will the sight of solider crabs gathering together in their battalions.
A sand beach, which may seem like a dull and dreary place, is actually teeming with life. Liu Hung-chang, a researcher of crabs, can spend hours at a time here. (photo by Cheng Yuan-ching)
Marching back and forth, soldier crabs are rounded on both sides. Not in awe of men, they often gather in groups and stand guard in their holes, like "courageous crab soldiers." The crab larva in this picture still has to shed its shell one time before it looks like a young crab.
In carrying out his investigations on the Hsiangshan coast of Hsinchu, Liu Hung-chang has recorded more than 30 kinds of crabs. After the tide recedes, the beach is littered with the small clumps of sand that crabs have removed from their holes. On the left from top to bottom, there is a "white-fan" fiddler crab, a soldier crab, and a Helice formosensis. On the right is a ghost crab, which can create noise by rubbing its antennae against its head, and a "net" fiddler crab, with a characteristic"smiling face" on its back.