MARlNE FISHERIES AND ENVIRONMENT IN THE ASEAN REGION

by

Suraphol ~udara '

ABSTRACT

Marine production is rapidly expanding in countries bordering the South China Sen and nearby seas, which include all ASEAN countries. Before 1960, even though annual cgml consumption in regional countries was 25 kg compared to less than 10 kg for people in most developed countries, the contribution of regional marine products to total world catch was estimated at less than two million tons /Sakiyuma, 1986). Fish caught in those days were predominantly small-size pelagic species, suck as mackerels, sardines and anchovies, and they were captured in inshore and coastal waters by n large number of small-scule or artisanal jkherfolks, employing traditional types of fishing gear, main!y stationary, such as stake traps, lift nets, set bag nets, beach scines and hooks and lines. The artisanal fisherfolks during this period used small and non-motorized boats.

In the region, the rising trend of:fish production carried on in the eighties and early nineties. In the nineties, aquaculture has also been contributing to landings. Estzmated annual fish production of South China Sea countries rose from about 2 million tons in 1950 to 8.9 mlllion tons in 1970, and to 25 million tons in 1991. Excludmg China. total production in 1991 was about 12 million tons or 12.6 % of total world catch {Menasveta, 1995)

Such a dramaric rise injisheries production has had inevirable consequence.s on coastal and marine ecosystems. Ove$shing and the use of destructive ,fishing techniques have led to the degradation of many valuable fish habitats, including mangroves, seagrass beds, ,and coral reefs. Unbridled expansion of aquaculture, particularly shrimp farming, has also contributed to resource depletion and environmental degradation. This gloomy picture is made worse by the impact o f land- and marine-based pollution, dredging, upland development activities, siltation, coral mining, and tourism.

1. MARINE FISHERIES IN ASEAN COUNTRIES

Of countries bordering the South China Sea, ASEAN members Thailand, Indonesia and the Philippines, in addition to China, were among the major producers of marine fisheries resources in the seventies. Malaysia also increased fish landings in the latter part of the seventies. Formerly, tropical waters such as the South China Sea were severally believed to have low productivities. However, the rapid development of marine fisheries after 1960 in these waters has confirmed that these areas are highly productive (Table 1). The major producing countries were China,. Indonesia and the Philippines. Excluding China, the value of the catch taken by ASEAN countries was estimated at US$6 800 million (Menasveta, 1995).

Department of Marine Science, Chulalongkom University, Bangkok 10330, Thailand.

Table 1. Total marine fish landings of the countries bordering the South China Sea

Brunei 2 Cambodia 21 7 36 34 China (PRC) 3 726 2 813 7 07 Hong Kong 132 187 220 220 Indonesia 836 1 395 2 380 2 692 Malaysia 325 734 904 1 024 Philippines 928 1 251 1 673 1 660 Singapore 15 16 1 1 9 Taiwan 611 759 308 326 Thailand 1 538 1 648 2 479 2 736 Vietnam 81 1 398 610 810 Total 8 945 9 212 17 118

Source: Menasveta, 1995 and SEAFDEC, 1992.

1.1 Factors contributing to marine fisheries expansion

The expansion of regional marine fisheries is due to the following factors:

(1) The introduction of new fishing techniques and equipment, such as monofilament nylon gill nets of various sizes, for artisanal fisherfolks, and trawl net fishing in the commercial fisheries sector;

(2) The improvement of fishing boats, including the use of motors; (3) The introduction of modern techniques with the assistance and

cooperation of developed countries; (4) Investment from developed countries for extra-infrastructures such as

processing facilities, cold storage, ice plants, etc.; ( 5 ) Opqations in new fishing grounds in the offshore areas of the South

China Sea and Indian Ocean; (6) Government policy aimed at promoting marine fisheries.

Formerly used for local consumption, marine fishery production changed after 1960 through higher demand from other inhabitants of countries outside of coastal areas. There was an increase in exports to developed countries of higher quality and value selected species such as shrimps. Joint investment between developed countries and key production countries in the region also contributed greatly to the expansion.

Even though trawl fisheries did not outnumber the small non-motorized boats of artisanal fisherfolks, trawlers contributed to the rapid expansion of marine fisheries in the region after 1960. In Thailand for example, the introduction of trawl net fisheries to Thai fisheries in the earlier sixties led to a tremendous increase in production. From 200 000 t of annual landing in 1960, it had increased to 1 400 000 t by 1970. By 1980, more than 85 % of the Thai marine fish catch was taken by trawl fisheries. The success of the Thai trawl fisheries led to the subsequent expansion of

trawl fisheries in Indonesia and Malaysia in the late sixties. Marine fisheries also increased notably in the Philippines, especially by artisanal gillnetting and purse seine and "basnig" nets for catching pelagic fish and fauna in coastal commercial fisheries (Menasveta, 1995).

1.2 Problems caused by trawl fishing

Intense trawl fishing in the Gulf of Thailand and also in other areas of the Sunda Shelf has resulted in smaller capture sizes of demersal fish and in changes in the species composition of the catch, whereby long-lived and higher valued species are replaced by short-lived and lower-valued species. Available fisheries statistics (SEAFDEC, 1993) indicate that at present more than 65 % of the trawl catch in the Gulf of Thailand consists mainly of trash fish, contributing only 16 % to total landed value. Regional trash fish production has remained relatively constant since 1978, about one million tons annually. There is still demand for trash fish, especially by animal feed and aquaculture industries.

The Philippines experienced biological overfishing in Manila Bay in the sixties and seventies. The past three decades has seen biological overfishing in the Gulf of Thailand, which has forced larger Thai trawlers to fish further afield in the South China Sea, in the Indian Ocean and other distant waters. There have been conflicts between trawl and artisanal fisherfolks along the coasts of Thailand. Malaysia and Indonesia have experienced the same problems. These developments led to the revision of fisheries legislation in Malaysia, including the zoning of fishing operations, and a ban on trawling activities in the Java Sea and part of Malacca straight by Indonesia in the early eighties.

It is believed that many demersal fish stocks in most parts of the region have been fully or overexploited. With the decline of predator species as a result of intense trawling, the population of cephalopods, mainly squids and cuttle fish, have increased substantially, now supporting both artisanal fisherfolks and commercial fisheries in the region. Regional cephalopod landings rose from 60 000 t in 1970 to 250 000 t in 1990. Cephalopods are the only resource from which a substantial catch can be made in many parts of the region. However, intensive fishing for cephalopods has been observed in the Gulf of Thailand, and it is believed that the resources have been fully exploited (~enasveta, 1995).

The decline in the abundance of demersal fishery resources has stimulated regional fisheries to increase the exploitation of pelagic fish stocks, using purse seines or purse seines with luring lights. A number of fishing grounds for small and medium-sized pelagic fish such as scads were discovered in the middle of the Gulf of Thailand. This contributed to the increased production of pelagic fish in the seventies and eighties. In the late eighties, about three million tons of these small and medium- sized pelagic fishes were caught annually.

Coastal pelagic resources in many areas of the region may also be fully exploited. In Thai waters, many of these resources have been overexploited, except Indian mackerel (Rastrelliger kanagurta), which could sustain an increase in fishing effort by about 20 % over the 1991 - 1992 level (Dept.of Fisheries of Thailand, 1993).

1.3 Oceanic fisheries

Oceanic pelagic fish such as skipjack and yellowfin tuna are fished mainly by Indonesia and Philippines. Estimated total landings of tuna and tuna-like fishes in the region was about 400 000 t in the late eighties. It is believed that the oceanic tuna stocks exploited by southeast Asian fisheries are part of the entire stocks widely distributed in the Pacific Ocean beyond the eastern border of the region. A moderate expansion of the fisheries in the region for skipjack and yellowfin tuna can be made as the exploitation of the Pacific Ocean stocks of skipjack stiH remain at a moderate level and the state of exploitation of the yellowfin tuna stocks is unclear (Menasveta, 1995).

1.4 Aquaculture

Aquaculture has only really started to develop rapidly during the past few decades, due to better knowledge of the species cultivated, improved methodologies and techniques in breeding and nutrition, and increasing demand for food fish from countries for higher-valued species such as shrimps, sea bass and grouper. Aquaculture production of the Southeast Asian countries rose' rapidly from about 3 million tons in 1972, to 9 million tons in 1990, representing a threefold increase.

In recent years attention had been focus on developing an intensive shrimp culture with a view to exporting the products. The culture of marine fish is not yet as intensive as that of crustaceans. This intensive shrimp culture in the region may have a negative impact on coastal capture fisheries and environment. In Thailand and Vietnam, mangrove deforestation for expanded shrimp culture activities has resulted in the losts of habitats for breeding and spawning of a number of commercially important species of fish, crustaceans and mulluscs and could have long term negative impact on coastal fisheries. With the conversion of one third (100 000 ha) of the mangrove forests along the Mekong tidal flats into shrimp ponds, it is observed that the ksh catch in the coastal waters of the delta region have decreased sharply with the annual catch of the Mekong fish species now down to 100 000 t (Interim committee for Coordination of Trevestigation of the Lower Mekong Basin, 1992).

From the study at a small river-mouth, welu estuary, chantaburi, the study showed a 65% decrease in mangrove area, resulkting from shrimp farm expansion. The result of relationship analysis between mangrove area and the production of the nearshore mangrove-dependent fisheries revealed a clear drop in fisheries production following extensive conversion of mangrove area in 1988. Average fisheries production decreased from 16 076.4 t (1974-1988) to 10 281 t (1989-1992), a 36.05% drop with a value of about 31 million baht per year.

Mangrove deforestation also has an impact on shrimp culture itself as the latter's success, if the traditional method of culture is used, depends on the amount of post larvae in the wild for stocking in ponds. For the intensive culture system, the number of spawners caught in coastal waters, which are used for breeding in hatcheries may decrease because the wild shrimp populations also use mangrove swamps as their feeding ground.

Other negative effects of mangrove destruction to make way for shrimp ponds in coastal areas include water pollution, due to release of pond effluents; sedimentation due to release of solid material from ponds; the interruption of the water flow regime; the introduction of disease causing organisms; the loss of natural shrimp and fish stocks due to increased pollutants and product contamination due to indiscriminate use of chemicals. In recent years, an epidemic was prevalent among intensive cultured fish and shrimp in a number of southeast Asian countries; this might have been due to mismanagement in fish culture, e.g. high stocking density, over-feeding, etc. Chemicals and antibiotics have also been used in fish and shrimp culture recently to prevent and control bacterial and virus disease; the implications for human health are not clear.

In order to ensure the sustainable development of aquaculture, it is felt that the countries should continue to refine aquaculture techniques, to promote environmentally friendly aquaculture practices, and to gain a better understanding of the ecosystems in which they would like to introduce aquaculture, bearing in mind their relationship to various socio-economic settings.

3. COASTAL ECOSYSTEMS RELATED TO FISHERIES

Coastal fisheries, particularly in tropical areas, rely to a great deal on the condition of coastal ecosystems because various parts of their life cycle depend on the coastal ecosystems, namely, mangroves, seagrass beds, soft bottom areas and coral reefs or coral communities. In the ASEAN region, the coastal ecosystems are deteriorating and that is threathening to the existing situation of the coastal fisheries which the ASEAN countries are depending upon both for their own consumption as well as part of their export products.

3.1 Mangroves

The present situation shows very clearly that various activities together with weakness in present management policies have resulted in massive mangrove losses in the ASEAN region and hence a loss of regional biodiversity. Loss of mangroves, as a grass estimate, in the ASEAN region during the past 50 years would be about 50%. The biggest loss has been in the Philippines and Thailand, estimated at 60 - 80%, about 50% in Indonesia and 30% in Malaysia. Most destroyed mangrove areas have been converted to fish or shrimp ponds.

Figure 1. The major mangrove areas and prawn fishing grounds of the ASEAN countries. Inset shows Singapore (mowed in map). , Information extracted fiom Gomez (1980), Chullasorn and Martosubroto (1986), Chan (1987), and Naamin (1 987), and Low and Chou (1 993).

Indonesia

Indonesia has mangrove areas of approximately 4.30 million hectares in Sumatra, Kalimantan, Java, Nusatenggara Sulawesi, Maluku and Inan Jaya (Ong, 1944). This is approximately 30 to 40 % of the world's total. However, this is approximately 66% of the original mangrove area. Mangroves have been continuously utilized in Indonesia for many purposes such as forestries, fisheries, agriculture, industry, settlement, mining and tourism.

The Indonesian government is aware of the economic importance of mangroves for fisheries and coastal protection and the current rate of mangrove degradation, and has implemented a conservation strategy by declaring 17.5% of the remining area as conservation forests and 25% as sustainable forestry areas. Much of the remainder, however, will be impacted during increasing development. Large areas of the forests on Java and Sulawesi have been removed to construct prawn and fish culture ponds (tambala). More recently, large areas of mangrove trees have been removed for the export wood-chip industry, particularly to Japan.

Coastal fisheries are important in the Indonesian economy, contributing 2.27 million tomes for local and export consumption, with much of this mangrove based. This amount is predicted to almost treble as the industry develops. Maintenance of the mangrove forests is seen as a vital component of this potential expansion.

The mangrove forests also contain some species threatened with extinction e.g. long tailed macaque, proboscis monkey, estuarine crocodile, and many bird species that use mangroves are either permanent or migratory habitats.

Malaysia

Malaysia has extensive areas of mangrove forests in both East Malaysia (particularly in Sarawak) and Peninsular Malaysia (particularly the west coast). These forests total approximately 650,000 hectares, with about 100,000 being in Peninsular Malaysia (Ong, 1994).

The mangrove forests are globally significant with the third largest area coverage of 647 thousand hectares, most of this in East Malaysia : 57% in Sabah ; 27% in Sarawak. Mangrove forests have decreased in area by approximately 35%, with large scale losses on the western side of Peninsular Malaysia through domestic, industrial and agricultural development, and in Sabah and Sarawak because of clearing for the export woodchip industry (Japar, 1994).

Probably the world's best example of sustainable mangrove use is found on the west coast of Peninsula Malaysia at Larut-Matang. An area or 40,000 hectares have been managed as forestry concessions for about 80 years with no decrease in productivity and an active fishing industry based in and around the forests. Mangrove saplings are used as scaffolding and fishing stakes with the mature trees harvested after 30 years for charcoal production ; this forestry industry is worth US $9 million per annum. Cleared plots either regenerate naturally or are replanted with seedlings. The fishery supports approximately 10,000 people yielding approximately US $80 to 150 million from prawns, crabs, finfish and molluscs, although there is evidence of over-exploitation with smaller stock being caught and catches decreasing.

Philippines

The best estimate of the original total mangrove forest in the Philippines comes from the Forest Research Institute which is about 500 000 ha in 1920. In 1965 this was reduced to 448 300 ha, and much further reduced to about one half (56.7 %) or 254 016 ha in 10 years. However, based on satellite imagery taken in the same year by the Natural Resources Management Center, remaining Rhizophora-dominatd forest was 106 133 ha. Such reduction in mangrove hectarage was due large to fishpond conversion.

In general, the area of mangrove forest in the Philippines has been reduced by almost 80% in the past 70 years with most of the losses being caused by clearing for fish and prawn ponds, collection of firewood, and clearing for human settlements. The current losses of mangrove trees are about 760 hectares per year with direct losses

to the economy of approximately US$ 1.7 million. These losses do not include reductions in fisheries productivity, which is based on the nursery ground function of mangroves. The Philippine mangrove forests are particularly rich in tree species (50) and fish (over 100 species).

Many of the mangrove reforestation efforts in the Philippines started in the late 1980s. In 1992, a total of 22 723 ha have been reforested with 986 reforestation contracts. Of these less than half (14 698 ha) have been monitored showing 0 - 64 % survival. In most cases, however, only the genus Rhizophora is used due to the ease in planting and monitoring, and the availability of propagules. In Bais Bay, about 55 ha of Rhizophora mucronata and R. apiculata were planted in 1991.

The Philippine Government has attempted reforestation of some degraded areas by issuing Certificates of Stewardship to local people and NGOs. This has shown limited success. The recipients have access to the firewood and increased fisheries of the areas, but the reforestation has shown only limited success.

An additional 18.5 ha in 10 sites have been planted with 0% survival (mostly R. mucronata), with 65% performed by CSC holders. The Certificate of Stewardship Contract gives the holder stewardship of a piece of land to be reforested, renewable for 25 years. A higher percentage of survival (68 %) was noted for non-CSC holders as against those by CSC holders (19.6 %). These observations do not augue well for the CSC holders calls for a re-evaluation of this strategy as a resource regeneration scheme for mangroves. Causes of low survival include predator attacks, especially by land crabs (Cardisoma), infestation with barnacles and oysters (Crassostrea), algal blooms (of Enteromorpha) covering newly planted and germinating propagules, and substrate unsuitability.

Attempts at multispecies reforestation are being undertaken. For example, in Bais Bay a multispecies mangrove nursery has been established and germination trials, survival rates and growth rates of several species are under investigation.

Singapore

There has been widespread destruction of the once flourishing mangrove forests during the development of modern Singapore with only 600 hectares present; 0.5% of the original forest area. Most of the forests have been cleared for industrial and domestic development as the area of the island state has been increased by 10%.

Some areas have been designated 'green areas' by the government, while some mangroves are retained in currently protected parks and bird sanctuaries. The absence of a significant economic rationale for conserving mangroves, coupled with the land needs of a rapidly growing and industrialising country, mean that probably only token mangrove areas will be conserved for aesthetic and educational purposes in the future.

Thailand

Mangroves in Thailand grow in 22 provinces in the eastern and southern parts of the country. Between 1961 and 1989, mangrove cover in Thailand, originally at about 367 900 ha, was cut in half, with the clearing for aquaculture ponds being responsible for more than 50% of the lost. A number of approaches have been adopted to try and to prevent the destruction of mangrove forests. In late 1987, a Cabinet Decision introduced three zones for mangrove forests in order to partition uses so as to avoid significant damage to important mangrove areas. The Preservation zone, because of it's value to the natural environment, would be strongly protected from any human impacts and no exploitative uses of it would be allowed. Economic Zone A would allow for forest utilization on a sustainable yield basis including charcoal production and locus uses. Economic Zone B would allow for other development with consideration given to the potential impacts on the environment. This approach has met with little success because of various reasons, the most important ones being: the weakness in law enforcement, a poor attempt to clearly demarcate the zones which made proper control difficult, and the lack of political will to face growing economic pressure.

At present, the Royal Forestry Department groups mangrove forests into 4 broad regions and the latest figures from Landsat-TM 1993 shows alarming destruction to all. In the Eastern region, along 502.4 km. of coastline, only 6.05% of the original mangrove cover remains. As for the Central region, with 439.2 km. of coastline along the inner part of the Gulf of Thailand, only 0.45% of the original mangrove cover is still left. Lastly, along 932.4 km. of Southeast coastline and 709.6 km. of Southwest coastline, mangrove cover is down to 8.05% and 85.45% respectively (Kongsangchai, 1994).

The rapid and continued growth of shrimp ponds into the good mangrove areas is now causing increasing destruction to the mangroves particularly along the southwest coast. The above figures should now be much less than what was quoted.

Despite the rapid destruction of mangrove forests, these is a widespread awareness in Thailand of the importance of mangroves resulting from the campaigns of both NGOs and government authorities. While this awareness may not be frequently backed by any depth of understanding of the way in which mangroves are beneficial, the breadth of awareness is probably greater than any other large country in Southeast Asia.

Coastal communities generally have a greater understanding of the importance of mangroves than the population at large. Often, they depend directly and indirectly on the mangroves for their livelihood.

Both government agencies and community groups have been involved in mangrove replanting programs. It is to be noted that not all their efforts are successful. The Royal Forestry Department has been involved in mangrove replanting for around 30 years. Prior to 1990, most of this activity was in mangrove concession

areas that had been logged by concessionaires and in mining areas. Replanting programs primarily made use of Rhisophora and Brugueira species.

As a result of growing concern over the rapid rate of destruction of the mangroves, a Mangrove Forest Development of Conservation Zone Project was established under a 1991 cabinet directive. The main objectives are to create a mangrove management strategy, to mark the boundaries of mangrove zones, to map out important areas for use in preventing more encroachment and to gradually replant the mangroves.

Areas where the mangroves have been cleared can be successfully replanted if these areas have not been converted permanently for other uses or claimed by a land title holder. An alternative practice in mangrove rehabilitation is to plant the seedlings or sabbings on mud flats seaward of the existing mangroves. Successful results have been evidenced in several places where the planting was done close to the mangrove forests. Oftentimes however, project supervisors were to .eager to gain tnore ground, and the planting of seedlings or sabbings was extended to far out into the sea. In these cases, the young plants usually did not survive perhaps because the mud flats were not yet in favorable condition for the growth of mangroves or the top of the young plants were expased to the attack of barnacle. Plankton studies can help very much in successful planting because mangroves should ideally be planted during periods of low barnacle larvae in plankton. (Sudara et al. 1994)

This difficulty shows very clearly that the rehabilitation process to extend the existing mangrove lines hrther seaward needs more scientific investigation into the nature of the problem preventing mangrove survival. Every year, a huge budget is wasted by planting seedlings or sabbings on the mud flats without success. Therefore, more studies on how to plant mangroves, 'as well as what could be planted and when to plant are still needed.

3.2 Seagrass

The seagrass ecosystems of ASEAN are the most neglected comparatively - both as objects of scientific research and as marine resources. While the region is characterised by a near-maximum variety of seagrass species and habitats, these are increasingly being degraded at an alarming rate by both natural and man-induced stresses.

In the last 50 years, research on seagrass ecosystems in the region focused primarily on the structural aspects of the resident and associated communities. The Indo-West Pacific region is the center of generic richness and diversity of seagrasses in the world. The highest number of species is found in the coastal waters of Malaysia bounded by Indonesia, Borneo, Papua New Guinea and northern Australia. The 16 seagrass taxa reported from the ASEAN region (i.e. Brunei Darussalam, Indonesia, Malaysia, Philippines, Singapore and Thialand) and to which at least two more could be added, make its marine submerged angiosperm flora second in species diversity to Western Australia, which has the highest in the world. However, seagrass distribution and ecolgy in ASEAN remain very poorly known.

Three countries :Philippines, Indonesia, Malaysia and Thailand have large resources of seagrasses and associated fisheries. It is in these countries that efforts have been concentrated in assessing seagrass resources and their importance in fisheries.

Indonesia

The large continental shelf around the western Indonesian archipelago, creates ideal conditions for the growth of luxurious seagrass beds. There are also extensive beds on the narrower shelves around the eastern islands. It is probable that Indonesia has the world's largest resources of seagrasses, estimated at around 30,000 km2 , but this cannot be confirmed as few studies have been conducted to measure seagrass area. Certainly, this region shares some of the richest biodiversity with at least 12 seagrass species and over 300 species of fishes in the seagrass beds.

In several places in Indonesia, the coastal population has had a considerable impact on seagrass macro fauna. For example, in Banten Bay local fishermen collect fishes by beach seine. In Kuta and Gerupuk Bays, South of Lombok the people collected molluscs, sea urchin and coral mining on the beds, the damage varied between 17.95% to 42.72% of the beds. The ecological effect of this superficial exploitation are of minor importance, but selective collection of animals over specific areas may have local influences on the biomass relation between seagrasses and larger benthic animals.

The main study area for scientists fkom the Indonesian Institute of Sciences is Banten Bay in far western Java, where recent industrial activities have resulted in losses of almost 80% of the seagrass beds. Disturbance by fishing boats has caused similar damage to the seagrasses on the coral reef flats of Pulau Seribu, to the north of Jakarta. Other study areas around Bali and Lombok show losses of seagrass cover.

A major concern in Indonesia are possible localized extinctions of dugong and marine turtles, which feed extensively on seagrass beds. These are being threatened by hunting and destruction of the habitat, particularly in heavily populated parts of Indonesia. One of the largest constraints against seagrass conservation is a lack of recognition by decision makers of the ecological importance of seagrasses. Few senior managers realise that extensive losses in seagrass cover will result in major losses to commercial fisheries.

Malaysia

With the available records based on written accounts, herbarium specimens and actual collection, there are 13 species belonging to 7 genera of seagrasses sparsely distributed over wide areas covering the west, east coasts and southern part of Peninsular Malaysia.

Ten species of seagrass occurring in the west coast includes one species, Ruppia maritima found in paddy lands or fields in Province of Wellesley, Prai, Penang growing in swamps, in brackish water close to the coast but apparently rare in

Peninsular Malaysia. The east coast has a total of 7 species of seagrass, mainly recorded in off-shore islands with fringing coral reefs in East Johore and a mangrove habitat in Terengganu. The southern part of the Malay Peninsula has a total of 11 species, the highest number in term of species composition ever recorded in one area comprising of the mangrove estuary of Sungai Pulai and the nearby Merambong shoal.

Little is known on threats to the seagrass resources of Malaysia. Losses of seagrass communities in the coastal areas of Malaysia caused either by natural processes or human activities generally pass unnoticed or unrecorded.

Of several human activities which affect the success of seagrass communities in the estuaries and coastal ecosystems, only a few have so far been considered as being deleterious. High sedimentation and total suspended solids in the water at Cape Rachado, Port Dickson as a result of the construction of a condominium on the beach, have reduced the numbers of Enhalus acoroides inhabiting amongst the corals. This suggests that subtle changes caused by human activities may have an impact on the growth of seagrasses.

Other human activities that may pose threats to the seagrass resources are mangrove clearance along the coastal areas (e.g. Port Dickson), land reclamation (e.g. in Perlis), coastal development (e.g. in Langkawi Island) and the proposed sand mining and deposition of dredge spoils along the coast off east Johore (e.g. Tanjung Rumania). These activities, without effective planning and mitigation measures, can cause an increased sediment load in the water and would produce adverse effects on the animal and plant life in such areas.

Philippines

The Philippines has very large areas of seagrass beds which may be pristine, disturbed, altered, or emergent, with 16 seagrass species having been identified. Highest densities occurred where monospecific stands of the smaller or finer species were found. Highest number of species were recorded in sandy-muddy areas, moderaterly protected from wind and waves. On the other hand, lowest number of species were recorded from areas either highly exposed to waves in hard, impenetrable bottom or highly protected from waves in mud substrate.

Human impacts include sewage and sediment pollution which causes a reduction in available light and smothering of the grasses. Dredging for port activities and trawlers also cause considerable damage, and can reduce the number of species to form altered seagrass beds. Disturbed beds have reduced productivity because of structural and pollution damage to the seagrasses.

Seagrass beds are also disturbed by storms and it is possible to detect signatures of past storm and other weather events (like El Nino Southern Oscillation- ENSO) in banding patterns in rhizomes or underground stems. Seagrass transplantation and the use of artificial (plastic) seagrass has improved considerably the biodiversity in a bay disturbed by the dumping of copper mine wastes.

The resource. management perspectives from the results of activities on seagrasses in the Philippines draw significance from the predictive value of the ecological and environmental outcomes. Current distribution patterns of the seagrasses, value of seagrass biomass, turnover rates, production, and recruitment and mortality rates are directly useful in planned and existing efforts in rehabilitation, restoration and coastal zone planning. Similar and related parameters have also been initiated for the fauna associated with the beds. Hence, information is now available on smgrasses with desirable structural and dynamic features, on areas in the bay suitable for transplantation, or areas suitable for multiple use, faunal species with resource and conservation potential, and those whose importance is yet to be elucidated for prospective planning. With the distribution and extent of the seagrass habitats in some of the areas known, the nature and relative abundance of the other resources associated with the beds (i.e. fishes, crustaceans) could similarly be predicted with reasonable precision.

Singapore

Singapore originally had relatively large areas of seagrass beds around the island. These have been drastically reduced following the large scale development of the island: land reclamation and dredging for port construction. The depth distribution of the seagrasses has also decreased due to large increases in the amount of suspended sediment in the water. The existing shallow water beds are disturbed by boat traffic and oil pollution from ships and industry.

The loss of seagrass beds has had little observable impact, despite its importance to fisheries as nursery grounds. This is due to the near non-existence of commercial fisheries in Singapore waters. There has been a reduction in subsistence fishing, but there was no evidence to link this with the degradation of seagrass beds, whereas increased economic activity and the availability of more lucrative employment are more likely reasons (Loo, 1994).

The remaining patches of seagrass beds fringing the southern coral islands grow in shallow muddy to sandy sediments. Recent study by scientists from the National University of Singapore have identified 7 species of seagrasses and 13 species of fish and 23 species of molluscs that live within seagrass beds.

Thailand

Seagrass resources in Thailand occur in both the Gulf of Thailand and the Andaman Sea. These beds are rich in biodiversity with 12 seagrass species and 67 speciess of fishes, including many of economic importance. These seagrass beds, particularly those in the Andaman Sea, support one of the last remaining populations of the threatened dugong and sea turtles.

The area covered by seagrass in the Andaman Sea was calculated by using aerial photographs and ground surveys to be apprdximately 50 km2 (not including mud or sand flats in the same area). These areas did not include some small patches

of seagrass beds where no study transects have been indertaken. These beds are productive with a dry biomass of 1.2 kg/m2, but degraded areas have much less. Damage has been caused by trawlers operating in the beds, although they are prohibited from operating within 3 km of the coast. Pollution and sediment from the development tourism industries of Phuket is also degrading the beds.

Seagrass beds in the Andaman Sea are more abundant than in the Gulf of Thailand in terms of plant density and area covered. For the Gulf, seagrass beds could be found all along the east and west coast. Degraded seagrass beds were found ik an area where considerable industrial construction, shrimp farms and land development were present. Therefore, adjacent seagrass beds were effectively destroyed by those activities which resulted in massive pollution in the Bay.

Human factors are the main cause of seagrass decline. The declining seagrass area in Thai waters is a direct result of illegal andlor destructive fishing methods. On the commercial scale, large trawl boats sometimes fish within the 3- kilometre legal limit from shorelines. At the local scale, destruction results from illegal dynamite fishing, cyanide fishing, small-mesh beach seines, and mechanised push nets. All of these fishing methods not only destroy the coastal environment and its rehabilitation capacity, but also exploit the juveniles of the important marine species, i.e. fishes, crabs, shrimp and moulluscs. Sometime endangered species, such as dugongs and sea turtles, are incidentally destroyed.

The effects- of human perturbation, such as siltation (from road construction near the shore and coastal tin mining) in the Andaman Sea is believed to be responsible for degradation of grass beds in 5 sites under investigation. Most seagrass beds are affected by the operation of mechanised push net boats.

Another example of the destruction of a seagrass bed near Khung Krabane, Chanthaburi Province, on the east coast of the Gulf is due to the polluted waste water from shrimp farming. It also appears to have caused a rapid decrease in juvenile groupers, which were collected for cage culture.

Among the sites studied, 40% were in pristine condition; 30% in good condition; with the remaining 30% in poor or degraded condition. Apart from restricting trawlers, the important measure to protect the seagrass beds is to control the nature of coastal development to reduce the input of sediment and pollution. The economic and biodiversity value of seagrasses needs to be conbeyed to decision makers and local fishermen, probably through the activities of NGOs. Such activities have resulted in areas on the Andaman coastline being protected to conserve the last remaining populations of dugong. Moreover, if fishermen appreciate the value of seagrasses to their catches, they will restrict damaging practices, in favour of safer and environmentally friendly methods.

3.3 Coral reefs

Over 30% the world's coral reefs are located in the ASEAN region, growing in shallow and reasonably clean waters. Coral'reefs are found in all six ASEAN countries, with the largest extent occurring in the two archipelagos of ndonesia and the Philippines. All reef types (fringing, patch, atoll, barrier) are represented in the region. The warm climate, constant nutrient source from land masses, and strong currents favour the development of reefs. Coral reefs are unique marine ecosystems supporting high biodiversity through the tight and efficient cycling of nutrients among associated organisms. The massive limestone framework is built through thousands of years by many different species of hard corals.

ASEAN reefs have been damaged considerably in the last 50 years. The rate of damage is apparently increasing, particularly over the past 10 years. It is probable that about 10% of ASEAN reefs have been severely damaged: the reefs around Singapore reclaimed; reefs in Jakarta Bay have disappeared because of mining or pollution; likewise reefs around major development areas such as in Thailand or the Philippines have largely disappeared under sediment and sewage.

Indonesia

The Indonesian island chain has about 17 500 islands with 81 000 km of coastline. These have probably the largest concentration and diversity of coral reefs in the world. Reefs contain at least 359 species of hard corals and many more species of coral reef fish.

In recent years, the coral reefs in Indonesia have been subjected to more and more stresses. Pressure on these resources comes from such diverse human activities as fishing, upland deforestation, agriculture, industry, tourism an drecreation. There is the tendency for these activities to increase steadily with time. The coastal environment is also affected by natural perturbations which may have serious impacts on coastal ecosystems.

Assessing the string of platform coral reefs and cays, Pulau Pulau Seribu, which stretch northwards from Jakarta Bay, the percent coral cover is declining steadily due to a combination of pressures, particularly pollution from the city of Jakarta and intense fishing activity, including dynamite fishing. Most (73.2%) of these reef, which do not experience strong natural disturbances, have coral cover less than 50% cover. Only 5.1% of the reefs in the zone of highest coral cover (at 3 to 10 m depth) can be described as having excellent cover (>75 %). The reefs in Eastern Indonesia with 69% of the reefs surveyed having only fair cover (<50 %) and 7% being in excellent condition. Most of these reefs are not impacted by pollution, but the fishing pressures and natural disturbances causing most damage.

Fishes on Indonesian coral reefs are being heavily exploited, with subsistence fishery catches on Pulau Pulau Seribu decreasing from 1,350 tonnes in 1973 to about 100 tonnes in 1990. There is a distinct correlation between a decrease in percent ocral cover and fisheries stocks, with both declining under human pressures.

Malaysia

Coral reefs of Malaysia differ remarkably from those on the heavily sedimented west coast of the peninsular to the oceanic reefs off Sabah. The majority (64 %) of reefs have fair coral cover dominated by the offshore reefs which have good coral cover ; a total of 346 species have been recorded. The fringing reefs on the west coast have fair to poor coral cover, about 27%, because of the high levels of sediment in the water. Reefs on the east coast of Peninsular Malaysia have fair to good cover, 60 - 70% live coral cover, except for the reefs of Pulau Tioman where intense tourism activity and crown-of-thorns starfish have resulted in a decrease in cover, about 27%. The reefs off Sabah have fair coral cover, about 50%, and those in the Spralty group, the atoll reef, have lower cover about 30% due to strong wave action and localised dredging activities. Recent construction of airstrip and sea-wall using mussive corals collected from the lagoon patch reefs reduced the live coral cover by almost 75%.

More than 320 species of fish have been recorded on Malaysia reefs, with the most species being on the eastern reefs. Coral reef fisheries provide from 7 to 35% of the fish landings in the west and more in Sabah (28 %), but these probably underestimate the true proportion as much of the catch does not reach the market. Fishing activity is generally not as intensive as other parts of Asia, however there are instances of the use of dynamite and poisons.

Philippines

The extensive surveys of coral reefs throughout the country showed that only 5.3% of the Philippines reefs have excellent coral cover, whereas 39% have fair and 30% have poor coral cover. These results are summarized from more than 740 different sites. While some of the damage to the reefs is due to the numerous typhoons that sweep across the northern islands, the persistent and long-term damage is a result of direct human stresses: over-collecting of corals and clams, destructive fishing practices like dynamite, muro ami and poison fishing. In addition there are massive indirect human impacts, particularly sediment runoff from large scale deforestation and mining, and sewage, agricultural and industrial pollution.

The recent volcanic eruption of Mt. Pinatubo in the Northwestern Philippines, had a considerable effect on the Zambales coastal environment because of the ashfall and subsequent lahar (volcanic mudflows). From an estimated 60 - 70% live coral cover before the eruption, a survey soon after the eruption showed the remaining live coral cover to be only 10 - 20%.

Coral reefs haye played a strong traditional role in Philippine culture. Reefs fringe most of the islands and their fisheries provided up to 36 tons per square kilometre, whereas the degraded reefs now only provide 10 to 15% of this. In addition, reefs have provided much material for the curio trade and now live animals for aquariums. Unfortunately, many of these benefits are being devalued as the reefs are being damaged by human activities.

Singapore

The small coral reefs in Singapore are amongst the most stressed in Asia. Singapore is a major port and the island has undergone massive land reclamation. This has caused considerable deterioration in water quality, such that corals that once grew below 10 m depth, now only grow in the upper 5 m.

There are 197 hard coral species on Singapore reefs. Percentage Iive coral cover ranged from 0% to 76% in the earliest survey. The upper limit of coral cover subsequently dropped to 72% and 69% in the survey later subsequent. Marked decreases were observed at the shallower water records in sereal sites.These sites have been subjected to anthropogenic and sediment stresses over the years. Anthropogenic stresses included coral fishing and use of fish traps on the reef flat and upper reef slone, removal of corals for the aquarium trade,and scuba diving and boating activities. Some sites were also subject to high levels of sediment. Increasing coastal development has led to increased sedimentation. The settlement and accumulation of sediment, and decreased light penetration at the lower slopes contribute to the decline of the reef community in terms of abundance and species richness. The effect of reef flat reclamation on the live coral cover at the crest and slope showed that live coral cover at the crest and slope was depressed on reefs with reclaimed flats compared to reefs with intact flats.

Diversity and abundance of reef fish were recorded and found that abundance and diversity decreased with depth, and increased with distance from the mainland. More than 107 species of fish occur in Singapore reefs.

Thailand

A. Gulf of Thailand 1. The inner part of the Gulf

The total coastline of Thailand is almost 2 600 kilometres, with over 300 major reef groups, covering an estimated area of 12 000 km2. These can be divided into four distinct areas of different oceanographic conditions, i.e. the inner part of the Gulf of Thailand, the east side of the Gulf of Thailand the west of the Gulf and along the coastline on the Andaman Sea. The majority of coral reefs in Thailand are either fringing reefs or coral communities growing on substrates other than limestone such as boulders and granite cliffs.

Coral reef condition in Thailand ranges from very good to very poor. Over 60% of all major coral reef groups in Thai waters are either in poor or fair condition. Less than 36% are in good or very good condition.

Since there are four major rivers opening into the inner part of the Gulf of Thailand, most of the coastal areas are covered with mangrove forest. Several islands in the inner part of the Gulf do have scleractinian corals which should be considered as coral community, rather than a reef formation. The coral communities on these islands have been damaged by over use, particularly by tourism. Islands closer to the shore show more damage than the others fkther away. In the Navy restricted areas the coral communities are still in very good condition.

2. The west coastline of the Gulf

Fringing reefs occur on many offshore islands which have become the target for considerable tourism development. These reefs were once heavily damaged by dynamite fishing, but now the most damaging impacts are due to uncontrolled tourism and the capture of live fish for aquarium export. Recent damage has been so severe on some reefs, which a few years ago had good coral cover, that they are now almost devoid of live corals.

3. The east coastline of the Gulf

Many fringing reefs on islands are occasionally impacted by typhoons. All reefs close to land have been damaged by sediment and pollution runoff from the land. This are includes some rapidly developing tourism centres with tourism numbers having increased from almost zero 15 years ago to approximately ! million per year. This increased activity resulted in considerable damage to the coral reefs with losses of cover of more than 20%.

B. The Andaman Sea

The Andaman Sea reefs are the richest in Thailand with the spectacular reefs of the Surin and Similan Island National Parks and many reefs around Phuket. Reefs close to shore, particularly those around Phuket, are showing damage from sewage and sediment runoff from tourism developments.

4. AN EXAMPLE OF COASTAL ECOSYSTEM CONSERVATION WITH COMMUNITY PARTICIPATION

Since 1987, when the Yad Fon Foundation began replanting mangroves with villagers in Trang province, the need for conservation activities with villager participation became very strong in the hope of spreading ecologichl awareness among coastal communities.

Seagrass conservation practices were introduced to many coastal villages located near seagrass beds. Afterwards, seagrass conservation activities, protecting the seagrass beds from being dektroyed by push nets or trawlers, came to be enforced

by the villagers. Eveqtually, they found that their catches improved and-that fishing was easier, which made them realize the importance of their conservation efforts. Thus, they expanded the area of protection and other villages followed suit.

From the record of catches made in waters around the seagrass beds, there is evidence that recovery from destruction of the seagrass beds could take less than a year and that catches were higher once the destruction was stopped. A large push net can destroy about 80 kg. of seagrass within one hour and (around 84 % of) the catch would only be composed of juveniles of economically important fishes, squids, crabs, and shrimps, all of which would be considered as trash fish.

The work of NGOs at Trang helped to bridge the gap between local people and local authorities through the co-management of the mangrove rehabilitation programme. Furthermore, the introduction of seagrass conservation practices to the coastal villages by scientists proved to be very successful when the villagers realized that they could improve their catches throgh such efforts at conservation. In order to better preserve their fishing territories, the villagers decided to extend their sphere of conservation to include the coral reefs upon the insistance of NGOs. They set up bouys to mark the boundaries of coral reefs in their area. NGOs also played a very important role in getting more authorities, such as the ONEB and the Fisheries Dept. to assist villagers in protecting their areas from the intrusion of trawlers and large push-net boats. Legally, these boats cannot operate within 3 km. of shore. This example illustrates the cooperation between the local villagers and authorities to strengthen law enforcement.

This success story at Trang spread among the coastal villages. Starting with 5 villages at Trang, similar conservation activities spread to more than 50 villages in the south by around 1990. Yad Fon and Wildlife Fund Thailand had been playing the leading role in organizing the meetinga of villagers with scientists and government authorities in order to strengthen local conservation practices. Their efforts resulted in the establishment of the Southern Artisanal Fisherman Federation. The federation provides an opportunity for local fishermen to get together to exchange information and voice their demands. Through the federation, they have asked the authorities for more stringent enforcement of the 3 km. limit and for help in various other aspects, such as to campaign on their behalf against certain policies and practices. The fishermen are also free to discuss their different needs with the authorities. For example, in some areas, they want the Fisheries Dept to construct artificial reefs which would serve not only to attract fishes, but also to obstruct the operation of trawlers and push-net boats. In other areas, however, they voiced their concern that artificial reefs would make it difficult for them to fish by traditional methods. Clearly, there is a growing sense of local participation in coastal planning.

In 1995, the local fishermen, the Fisheries Department and the governors of 3 provinces, Phuket, Phangna and Krabi, signed agreements with the Deputy Minister of Agriculture to develop joint efforts at conserving the natural resources within their respective areas. The villagers even built a center for officers to patrol the coasts.

Conservation of natural resources and coastal ecosystems also involves other actors. Private investors represent another influential sector in coastal zone management, and they can bring increasing economic pressure. Industrialization, tourism, land development agriculture and even aquaculture, can all produce tremendous change in landuse patterns, provoking degradation to coastal areas and changes in local lifestyle. It is therefore very important that the investment sector be involved in coastal zone management to avoid conflicts with environmentalist and conservationist groups. NGOs can bridge the gap by involving private investors in the process of co-management. They would be invited to participate in discussions to solve conflicts or to plan out manegement strategies.

Practicable solutions for an integrated coastal zone management plan necessitate the joint involvement and efforts of five sectors: local people, government authorities, scientists or academics, private investors, and most importantly, NGOs, whichserve as the catalysts, facilitators and initiators.

5. CONCLUSION: COASTAL ECOSYSTEM LINKAGES AND THE IMPORTANCE OF INTEGRATED CONSERVATION

Fortes (1994) suggested that material export, high interhabitat similarities in fish crustacean, and epiphytic algal community composition provide strong evidence of close hctional linkages between mangroves and seagrass ecosystems. Poovachiranon (1994) reports from a study in Thailand that from 71 species of fished captured fiom a seagrass bed and 69 species from adjacent mangrove creek, 45 were found in both habitats.

Artisanal fishermen at Petchburi in Thailand reported that cockle culture on the mudflats in front of the mangrove was less successful after most mangroves had been cleared for shrimp pond construction. Few years ago when conservation activities of the local people had been set up and rehabilitation of mangrove proved to be successful the population of cockles have been increasing. The cockly seeds which used to be so low up to the point that they had to buy seeds fiom other areas, has now become richer, and they almost do not have to buy them. Nutrients from mangrove help in producing enough food for cockles to grow in larger quantity as they used to be in this area.

Sudara, et al. (1992) demonstrated the interrelationship of fish communities between coral reefs and seagrass beds. The movement of reef fishes to seagrass beds demonstrates the connection between these habitats.

As is well known, many mangrove and reef fauna, i.e., mud crab gropers, cockles, etc. either migrate out to the sea to release their eggs or larvae in planktonic stages. These larvae would be transported far afield. During the juvenile stage, they usually stay in seagrass beds, which provide them with better shelter from predators as well as food. Upon approaching adulthood, they migrate either to the mangrove or to the coral reef as their final habitats.

If each ecosystem were dealt with individually in conservation, the ontogenetic cycle of these fauna could not be completed since they need all these habitats at some point in their life cycle.. Hence activities cannot be dealt with separately in a successful conservation approach.

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