INTRODUCTION
Along the shores of Thailand exist "the rainforests of the sea," better known as mangroves. In recent years people have begun to notice that these rich ecosystems are disappearing. The rapid disappearance of mangroves is often blamed on aquaculture, particularly shrimp farming, but there are many other factors that could potentially be held accountable for this habitat loss. Many references state that shrimp farms are the largest single cause of mangrove destruction, but the numerous other "bad guys" include: community development, agriculture, road development, ports, salt farms, mining, charcoal fuel, and wood extraction. All of the above can potentially be placed under one category of "urban development", because the above listed problems would not exist at a large scale if there had not been such a large increase in population and urbanization. When combining the other causes, and the most widely quoted number for destruction of mangrove habitats for shrimp farming (32%); urban development in Thailand accounts for a whopping 68% of mangrove destruction (Menasveta 1997).
Why are we so concerned about this loss of mangrove habitat in the first place? Though mangroves are not as well known as rainforests, they are arguably just as useful, especially to the local residents who rely on them for their day to day survival. A mangrove’s four main types of values are; physical protection of river banks and coasts (mangroves help prevent soil erosion), the economic value derived from forest products (wood, fish, etc.), conservation value, and the potential value of drugs, chemicals, and genetic resources. The paradox here is that each of these values is needed more and more as the local and global populations grow, yet the growing population is what is damaging the future of this valuable resource through increasing urbanism. This increasing urban development in turn leads to the greater need for shrimp farming to feed more mouths and the pollution that comes with more people.
So how can Thailand curb their rate of destruction of the mangroves? Such a loaded question does not have a simple answer. Between 1961 and 1993, 55% of Thailand’s mangroves were lost. An incredible 47% of them were gone by 1987, and in the next 6 years, only 8% were destroyed.
This recent reduction in destruction looks promising, as if we have progressed greatly in recent years. The original vast destruction which was caused by many factors such as urban development and aquaculture, especially the extensive aquaculture system, has subsided, only to be replaced by a better aquaculture system. The new system is referred to as intensive culture, which causes only minimal destruction in comparison to the unsophisticated extensive culture system (Menasveta 1997). But there are also the many complications that come with the rapid urbanization that has been going on in Thailand in recent years. The shrimp industry is confident that because of their new technology and education of the new shrimp farmers in their advanced ways, they will no longer be destroying any more of the mangrove areas than they already have.
MANGROVE ECOSYSTEMS
Located along tropical shorelines, mangrove ecosystems are defined as a "complex plant community below the high tide level, typically found on flat coastal land in areas of high, year round rainfall. They are one of the world’s most productive ecosystems in terms of gross primary production" (Costa-Pierce 1998). Because of their immense productivity, they are obviously very important and vital to the survival of the nations that make use of their many products. The values of mangrove ecosystems can be classified into five categories: their inherent value of the ecosystem itself; value to fisheries; the protection of shorelines; the habitat they provide for many species of plants and animals; and as a potential repository for wastes.
The mere existence of a mangrove forest in an area can be very beneficial in many ways. Mangroves provide the area with fishery and forestry products through aquaculture and logging, and is a place for sometimes profitable recreation and tourism.
Value to Fisheries
Much of the world’s fishing is done in the open ocean and in fresh water. However, there is also a significant amount of catch from fisheries located in mangrove ecosystems. Mangroves are the perfect place for young fish to feed and reside because of the protein rich food source from leaf litter decomposed by bacteria. Fish are also often protected from predators in these ecosystems, increasing productivity of the catch.
Protection of Shorelines
Mangroves are a great source of protection from erosion for shorelines, roads, and other pathways because they stabilize the land of the estuarine zones where they reside with their extensive root systems. They are considered an "ecotone", or transitional zone between two major ecosystems, tropical forests and sandy beaches that lead to the marine ecosystem.
Habitat Provided
There are five different varieties of habitats for the flora and fauna of mangroves. The highly diverse forest canopy is a terrestrial environment rich in many species of birds and orchids. Quite a few species of snails and anaerobic bacteria reside in the soil of mangrove ecosystems, while insect larvae choose the freshwater environment of root holes and clefts. Branches and aerial roots are inhabited by various filter feeders such as barnacles, oysters, and mussels. The larger species that we more often think about because of their value for human consumption, such as shrimp, crabs, fish, snails and frogs live in the permanent and semi-permanent pools of mangroves (Lindestrom et al. 1979).
Waste Repository
Like their cousins the wetlands, mangroves are very valuable as ecosystems that absorb nutrients and can survive in very adverse conditions. This makes them a target for waste repositories, as they would be able to naturally filter out nutrients from point and non-point sources that could potentially threaten delicate coastal zones if they were to be released straight into the ocean. These wastes can also be treated in plants before their release, but the use of mangroves as a filtering device could potentially be a more economically feasible and natural solution. Mangroves have been proposed as "alternative, low cost sewage treatment system[s]" (Clough et al. 1983), and as "possible repositor[ies] of effluents and sediments from shrimp aquaculture" (Rajendram and Kathiresan 1997). In theory mangrove ecosystems are ideal waste repositories, yet in reality it is quite possible for them to be overloaded with nutrients and degraded or even destroyed if the wastes deposited in them exceed the ecosystem’s capacity to filter things through without harm to the surroundings.
SOCIAL ASPECTS:
Just as the mangroves of Thailand are adversely affected by the surrounding population, so are those people in turn facing the negative consequences of their own collective actions. There are numerous aspects of mangrove loss that result in social problems and cause them, many having to do with shrimp farming, and many others a part of the economic cycle which takes place in any industrial or industrializing nation.
Shrimp Farms
Starting with shrimp farms, because they are the
largest single cause of problems, their coastal location (in the mangrove
forests) has denied the use of these areas that were previously available
to local residents for traditional every day activities such as fishing,
hunting, and the gathering of construction materials, fuels and other foods.
When it seems like the nation as a whole would benefit from the profits
that their natural resources produce, in reality it is only a select few
entrepreneurs, government officials, and foreign experts that get anything
good out of the shrimp farms. At the same time, the local residents suffer
because they can no longer live as they used to, fishing and gathering
things from the mangroves on their own, but now are forced to exist on
the very low wages they receive as employees of the money-making shrimp
farms. One of the biggest problems, which I believe leads to the overall
downward spiral is that the shrimp produced by these farms near the mangroves
is all exported out of Thailand. The money earned by the exporting of the
shrimp is good economically for the previously mentioned few, but disastrous
for the local citizens’ need for protein consumption (Bailey 1988). Because
they do not keep enough of the shrimp that is grown in Thailand within
the country, and local "trash fish" (which, contrary to their name are
commonly food for people) are also used to make shrimp feed for these farms,
there is not much "good" fish left for Thailand’s people to eat!
Population Growth
A combination of factors are responsible for many of the things that are destroying mangroves in Thailand to the present day, all beginning with social issues. Rapid population growth causes a greater need for food and shelter, both things that have had impacts on the mangroves mainly through pollution and overfishing. But how can this population explosion be curbed? The lack of food is obviously not preventing people from having more children, because they do not yet understand the present and future ramifications of their increasing the already unsustainable population in the area. Education of the local people, perhaps through incentives or good example of the well-educated shrimp farmers in the area is the key, but unfortunately the examples that are being set are more bad than good. As Alfredo Quarto of the Seattle-based Mangrove Action Project stated, "the long-term future of these places and people is being sacrificed for short-term gains"(Shaw 1996). Because they see the professionals of the shrimp aquaculture business in particular exploiting the natural resources of mangroves for monetary purposes, the citizens of Thailand conclude that it is acceptable for them to do the same, for their own livelihood.
When developing management plans for mangroves, a good way to help alleviate the social concerns of the local residents is to involve them in the policy making decisions. If they had more of a say in what was going on around them, as it greatly affects all aspects of their lives, perhaps they would be more likely to try to change their ways. This would mean altering their personal fishing methods to make them support the sustainability of mangroves and other areas through the prevention of overfishing and addition of unnecessary pollution to the surrounding ecosystem.
UNDERSTANDING AQUACULTURE
So far we have discussed extensively the fact that there has been a large amount of destruction of the world’s and specifically Thailand’s mangrove ecosystems. Much has been said about the fact that shrimp aquaculture is one of the main factors in that destruction, but we have yet to understand what that aquaculture consists of and why the destruction from it has declined in recent years.
Extensive Aquaculture System
The extensive culture system was the first and most primitive system developed for shrimp farming. Based on the same idea as hunting and gathering, the extensive system utilized mangroves in a large proportion because they were areas where the people noticed a large amount and mass of species, and it was easier for them to catch and gather the fish and shrimp here than it was out on the open ocean. Because of the ease of fishing in mangroves, fishermen soon converted large sections of mangroves into trapping ponds for shrimp and small fish (Menasveta 1997). Mangroves were also ideal for aquaculture because of their "gentle slopes, adequate tidal range, abundant wild shrimp seed, and land ownership vested with the government" (Menasveta 1997) which made their use very inexpensive. A problem with the extensive system was that because of its low stocking densities it had very low productivity, while at the same time being very destructive to the ecosystem. Because of this, soon new technology was developed.
Semi-intensive Aquaculture System
Because of an increasing demand for food as a result of increasing populations and industrialization in Thailand, shrimp farmers soon developed the semi-intensive system in 1980 to increase their yields. They were created by intensifying existing extensive systems, meaning there were now more food, fertilizers and pesticides used to increase the target species, and decrease unwanted species in the area such as predators. There were also many more interventions by humans of the mangrove ecosystem, in order to have more control over the activity in the ponds, which ended up being very destructive.
Intensive Aquaculture Systems
As mentioned previously, the destruction of mangroves
by aquaculture decreased rapidly after 1986, and the decrease was due to
the introduction of the more technologically advanced and efficient intensive
culture system. The new system was much more productive, yielding 6-10
mt/ha/crop more than previous methods, and more importantly, did not require
the use of mangrove (Menasveta 1997). In fact, mangrove ecosystems are
not compatible with the intensive culture method, so all at once shrimp
production increased, mangrove destruction decreased, and farming area
decreased.
| Before Modernization After Modernization | ||||||||
| 1961~1986 | 1987~1993 | |||||||
| 26 Years | Time Span | 7 Years | ||||||
| Extensive & Semi-intensive | Shrimp Culture System | Intensive | ||||||
| Rather Primitive | Culture Technology | More Advanced | ||||||
| 283,548 (1986) | Shrimp Culture Area (rai) | 449,292 (1993) | ||||||
| 17,886 (1986) | Annual Shrimp Production (mt) | 225,514 (1993) | ||||||
| 63 (1986) | Productivity (kg/rai/year) | 502 (1993) | ||||||
| 1,100,076 | Destroyed Mangrove Area (rai) | 173,458 | ||||||
| 42,311 | Mangrove Destruction Rate (rai/year) | 24,780 | ||||||
| 47.26 | % Mangrove Destroyed in Period | 7.45 | ||||||
CAUSES OF MANGROVE DESTRUCTION
The largest threats to mangroves are said to be clear cutting and land reclamation, pollution, the removal and diversion of freshwater sources to mangroves, and shrimp aquaculture (Deirberg & Kiattisimkul 1996). So if there is such a large threat by a variety of sources, then why is shrimp aquaculture always the most popular culprit to blame when we notice that our mangroves are disappearing? Every threat stated above other than aquaculture can essentially be contributed to urban development directly. Even aquaculture can be related to urbanization indirectly if we consider it as a way to produce the extra food needed to support a rapidly industrializing population. Perhaps urbanization does not take as much blame as it should because it is difficult to pinpoint one particular part of it of which the specific impacts can be readily seen by the people. Conversely, aquaculture takes more blame because people hear about only its negative impacts every day.
Urban Development and Population Growth
In eastern Asia, where there is extremely rapid population growth, there is a fear that soon the land there will not be able to sustain such a large number of people. Environmental and social sustainability of mangroves are threatened by the very numbers of people who depend on them for survival, because their numbers are becoming so large (Pimental 1997). Though the population of the entire earth is growing exponentially, there is much more concern about developing nations because if their extremely high birth rates, and subsequent need for immense amounts of food and resources. Thailand’s population in the early 1960’s, when mangroves first started to disappear was 26, 257,916. It has since more than doubled, reaching 54,548,530 people by 1990 (NSO, 1998). Mangroves are one of the main sources of aquatic protein and other necessary resources such as firewood and charcoal that are presently and will continue to be exploited in order to support Thailand’s development and growth.
Urbanization
As any ecosystem would be affected negatively by urban expansion, mangroves are especially, because until recently they were considered wastelands and had no efforts to preserve them, and they are often exploited to a damaging extent for the resources they provide. A large proportion of the expansion of coastal cities is not caused by natural population growth, but rather rural to urban migration, with people leaving the more rural inland to try their hand at aquaculture or some other technologically advancing occupation in a coastal city. Moving to urban areas is especially popular in Thailand because of the opportunities that the coastlands provide for fishermen and other professions. The trend to live in coastal zones has its consequences on mangroves. Rapid urbanization often causes an immediate demand for more land on which to house people, and mangroves are often the areas that are cleared to provide this land. A larger number of people in any area also means that there are more waste products produced, which are often dumped into mangroves and lead to their destruction. The negative effects of the destruction to the people that utilize them are not immediately evident. This is especially true in developing countries like Thailand where people must live day by day, and they often only see the mangroves for their present economic value, where in reality they are very necessary to preserve for their future survival and sustainability of the people. Loss of mangroves for urbanization along coastlines can cause flooding of coastal areas during storms and wipe out an area of new development that needs the protection of the mangrove forests that it destroyed. Another problem that urbanization of coastal zones brings to mangroves is a greater need for food and employment opportunities to sustain the many new residents of the area. The need for higher incomes to support themselves in an industrializing nation like Thailand is most likely met through using mangroves and other nearby areas for shrimp aquaculture.
Shrimp Aquaculture
There is a great deal of controversy over how much mangrove destruction is caused by shrimp farms. It cannot be denied that they have caused some, perhaps a significant amount of destruction, but exactly how much is debatable, and the numbers at present seem to be steadily declining. The most commonly stated statistic I was able to find about the distribution of sources of mangrove destruction is as follows:
The above information is based on research done by the Thai Royal Forestry Department, the Department of Fisheries, the Land Development Department, and the National Research Council of Thailand. I tend to rely on these sources as being more reliable than some of the others that I have found because of their location, and basically unbiased interests (because of their lack of potential financial gain). However, I would also like to discuss other statistics, and the discrepancies between them to understand the many biases that exist when statistics like those above are complied.
Menasveta (1997) states that "[even] though 17% of the historic mangrove area has been utilized by shrimp farming activities in the past, the shrimp industry is confident that there will be no further destruction from its sector". The 17% of total destruction of Thailand’s mangroves is in accordance with the above table of statistics. But when we look at other sources of information, we see some very different results. In an article by Daniel Shaw (1996) in Seafood Leader Magazine entitled "Shrimp Under Fire", many environmental groups have gotten together to prevent aquaculture from destroying any more mangrove area. In the article, FAO says that 50% of the world’s mangroves have been destroyed in all, and that half of that destruction was caused by shrimp farming. The article by Shaw also states that "published reports say" Thailand has destroyed 87% of their mangroves solely through shrimp farming, a much higher number than any other source finds, most likely because of environmental groups’ aversion to shrimp farming.
The Asian Institute of Technology (Hambrey, et al.
1997) has yet another opinion of the amount of mangrove destruction caused
by various sources. AIT says that over 70% of the Gulf of Thailand’s mangrove
area has been destroyed by shrimp farming, clearing for housing projects,
sites for industry, and salt farming. So this statistic does not get into
the specifics of just how much of the destruction was due to shrimp aquaculture
alone, but still contrasts with most other available information about
the total mangrove destruction. The following table is a quick reference
for the contradicting information about mangrove destruction that has been
obtained:
| Source | Total
Destruction |
% Total Destruction
from Shrimp |
Total
Destruction |
| Aquaculture Asia (1997) |
|
|
54.7% |
| Shrimpcom (1996) |
|
|
50% |
| AIT (1997) |
|
|
70.00% |
PROBLEMS
There are numerous problems associated with the difficulty of preserving delicate mangrove ecosystems. Some stem from social and political views and the complications that come with conflicting views. Others are the results of the monetary and technological limitations that countries like Thailand, a developing nation. Here I will discuss how and why the problems that exist in preserving mangroves originated. It is also important to know what we are doing to alleviate problems at the present, and the many options that we will be able to use in the future to solve, or at least lessen the massive destruction of Thailand’s mangrove ecosystems.
Social and Political Problems
Many social divisions of a country or culture are the result of political divisions which often determine or are determined by social class. In Thailand, shrimp aquaculture is a primary occupation of many citizens, and is also their primary source of income, especially for the poor. Because of their inherent value for many things, above all aquaculture and its profits, mangrove areas are in high demand. As we all know, those with the most power, whether it’s political or monetary, often both, are the people who win the battle of who gets to use and profit from mangrove ecosystems. Essentially, the biggest social and political problem is that the rich and powerful are the ones who get to use mangroves and reap all the benefits of their fruitful harvest, while the poor and powerless are often the ones that are left to absorb both the economic and environmental costs ensued by mangrove destruction.
Thailand’s Crisis
Both physically and economically, there is a need in Thailand for aquatic protein, and that need is satisfied with shrimp, often grown in or near mangroves, sometimes degrading valuable ecosystems. While the rich of the country can now afford to use the intensive system to produce shrimp in mass amounts, the poor farmers that only need to sell their small crops to keep themselves alive are the ones who suffer. Generally, they can only afford to continue to use the extensive system, which is being phased out by the more profitable intensive system to meet the increasing demands of the market for aquatic protein (Menasveta, 1997). So where does this leave the small time shrimp farmers who still depend on mangroves to grow shrimp? At first we might think that they are simply out of luck, but there are options available to them, if others are willing to help out. A good solution for the peoples’ economic problems and the mangrove’s environmental problems is the education of all shrimp farmers. They can be taught the importance of the ecosystems that they are destroying, and how to use new methods, such as the intensive system to continue making a living, while leaving themselves a place to make a living in.
Available Options
Now that we have outlined and explained the problems that exist in the battle to preserve precious mangrove ecosystems, we need to consider and understand the options that are available in order to restore them, or at least salvage what is left of the mangrove forest area in Thailand.
Zonation
In December of 1987, the idea of mangrove zonation was established in Thailand, which divided the area into three zones. They were as follows: "Conservation or Preservation zone; Economic zone A; and Economic zone B (Hambrey 1997). In the Conservation zone, the key concept there is that there is to be no more utilization of those areas whatsoever. The mangrove habitat in those areas is to be completely protected and preserved in its present state, and improved by reforestation. The next area, Economic zone A, is one of an intermediate level of regulations for protection of the ecosystem. Here all illegal activities that utilize mangrove that were once overlooked will be stopped, and only a very few limited activities still be allowed, and these only if they comply with the cabinet’s new rules and regulations. This area will also go through a process of restoration wherever possible. Finally, Economic zone B will have the most relaxed, yet still fairly stringent regulations. Here fisheries, mines and other activities will generally be allowed, but only after environmental impact studies have been done, and the desired activity has been found not to have a large detrimental affect on the surrounding mangrove ecosystem (Hambrey 1997). Hopefully, this system will help stop, and, if we are very optimistic, reverse the environmental destruction that has occurred to Thailand’s mangroves. But what kinds of deleterious effects do such specific and strict laws have on the people of all social and economic classes that depend on mangroves for their survival?
Feasibility for Everyone
As I mentioned before, the shrimp industry that once
primarily utilized mangroves has now mostly shifted their attention away
from the actual mangrove, and begun to use the land just inland from it
for their intensive culture systems. So as long as they are not overusing
their neighboring ecosystem as a waste depository, then the wealthy productive
shrimp farmers are in good economic shape. But those who work on a smaller
scale and still need to utilize mangrove areas for their extensive methods
of aquaculture are out of luck when we enforce the aforementioned mangrove
zonation laws. We can teach them everything we know about the more efficient
and advanced intensive aquaculture system, but it still might not be technically
feasible for them to use it. Menasveta (1997) states that the extensive
system is still used by poor farmers "who depend on shrimp farming for
their livelihood, and it is important not to take this away from them",
but he does not propose any means by which to help these farmers afford
to use the more advanced technologies. I believe that the only means of
doing this will be by perhaps hiring the poor farmers to work for the more
affluent members of their community, who are profiting greatly from the
huge demand for their product, the shrimp raised in their intensive ponds.
After so much discussion about what destroys valuable
mangrove areas, how do we know what the best way is to save them? Experimentation
is the only thing that will give us a clue. I believe that many different
methods must be applied at first, and the most effective few should be
continued. It is hard to say what is the best at this point in time because
socially and economically, there have not been enough advances in Thailand’s
coastal communities to implement remediation or protection plans whose
positive, negative or perhaps nonexistent effects can be seen as yet. But
if I were forced to try to foresee the future of mangrove protection, I
would say that zonation is our best bet because it is a very comprehensive
plan. Not only does it lay some ground rules for present protection of
mangrove areas in general, but it also contains some mitigation measures
and more specific guidelines for the use of mangroves in the future. If
a plan like this proves to be effective, the people of Thailand may very
well be successful in preserving their mangrove ecosystems so that they
will be able to continue to take advantage of their many values in the
future.
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