Maarten Kuijper1 and Oscar Pacheco Urpí2
1IOC/WESTPAC, c/o National Research Council of Thailand (NRCT), 196 Phaholyothin Road, Chatujak 10900, Bangkok, THAILAND
2Proyecto Desarrollo Rural Integral Peninsular, Apartado Postal 315, Puntarenas, COSTA RICA
Mangrove cockles (Anadara spp.) constitute an important shellfish resource in Southeast Asia. It is less known, however, that some Anadara species are also caught on a commercial basis in estuarine areas on the Pacific coast of the tropical Americas. Although the quantities harvested are smaller, they do represent the main source of income for a significant number of marginalised fishermen and women. Lacking the financial resources for buying fishing gear, these people dedicate themselves predominantly to the harvesting of these bivalve molluscs.
In Costa Rica, exploitation levels of mangrove cockles have in most places reached a stage where there are clear signs of over-fishing. The rehabilitation of coastal ecosystems is often perceived as restoring the physical appearance of an altered ecosystem with production considered to be a benefit in the long term. Restoring production however is a first priority for those local communities who depend on a particular ecosystem economically.
In the framework of an integrated rural development project with a coastal zone management component, an attempt was made to improve the livelihood of the marginalised fisher-folk, while at the same time to develop strategies to ensure the recovery and sustainable production of the mangrove cockles. A one-year ban on mangrove cockle gathering was established during which participatory research was carried out on aspects of the population dynamics of the cockles. Although the ban was successful in terms of compliance on the part of the local community, natural recovery turned out to be insufficient to sustain previous fisheries exploitation levels once the ban was lifted. Community management was introduced as a strategy for sustainable production after the ban with varying success. Obstacles had to be overcome at all levels of government because co-management was a new concept in fisheries management for Costa Rica. Most problems arose, however, at the grass-root level. Some of the implications of the introduction of co-management in Costa Rica are discussed. One of the outcomes of the study was the recognition of the need for an integrated coastal management approach covering the whole estuary. Steps are currently undertaken towards this goal.
J.A. Rubin1, C. Gordon2 and J.K. Amatekpor2
1 Institute of Marine Studies, University of Plymouth, Plymouth, PL4 8AA, UK
2 Volta Basin Research Project, PO Box 209, University of Ghana, Legon, Accra, GHANA
Halophytes growing in the study area consisted of two mangrove species, Avicennia africana and Rhizophora racemosa, together with grasses, ground-creeping angiosperms, the bulrush Typha domingensis and the fern Acrostichum aureum. Vegetation occurred in mono-specific patches, varying from a few m² to several hectares in size. Multivariate analysis of environmental data, collected in the field, revealed three distinct assemblages: one was dominated by A. africana and two other species, another contained T. domingensis, while the third contained R. racemosa and A. aureum. The consequences of the presence of the Volta Dams included gross overcrowding of R. racemosa seedlings and the total absence of recruitment in A. africana. However, exploitation of mangroves has increased simultaneously, as a result of the collapse of fishing and agriculture, both of which are additional consequences of construction of the dams. Suggestions are put forward which would increase biodiversity, improve mangrove timber yields and provide sustainable, alternative livelihoods for the local inhabitants. These include replanting programmes of both mangrove species in areas currently occupied by weed species which occur in the same assemblage as each of mangroves; that the SE Asian palm Nypa fruticans should be introduced artificially; and the development of low impact tourism in the project area.
K. Kathiresan, N. Rajendran and V. Palaniselvam
CAS in Marine Biology, Annamalai University, Parangipettai, 608 502, INDIA
Depletion of mangroves has caused loss of soil fertility, coastal erosion and a steep fall in fishery resources in many parts of tropical Asia. To reverse these losses, the reforestation of denuded mangrove areas is often carried out. As part of a research project at CAS in Marine Biology, Annamalai University, we have planted the seedlings of mangroves in a degraded area at the southeast coast of India. The seedlings comprise ten species, viz., Aegiceras corniculatum, Avicennia marina, A. officinalis, Bruguiera cylindrica, B. gymnorrhiza, Ceriops decandra, C. tagal, Excoecaria agallocha, Rhizophora apiculata, and R. mucronata, which are grown over a coastal stretch of 1.5km. The growth performance of the seedlings, and 28 other parameters including primary productivity, nitrogen-fixing microbial counts, prawn seed resources, soil fertility and environmental characteristics, were measured at monthly intervals for two years from July 1995 to June 1997. The use of mangroves to improve coastal ecology has been well demonstrated. Further monitoring and scientific management of the artificially developed mangrove plantations which are presently in progress are discussed in this paper.
Pranabes Sanyal
Environment Ministry, Government. of W. Bengal, INDIA
The Sunderbans is one of the largest mangrove patches in the world, and the world's largest accreting delta situated at the estuarine region of the Ganges - Bramhaputra river system. During the 17th century, this delta contained nearly 20,000 sq. miles of mangrove forest. Owing to anthropogenic impacts like reclamation, the intertidal area became increasingly encroached upon by human habitation. Continuous embankments along the creek were erected to create farmlands and brackish water aquaculture ponds. As a result, the intertidal mangrove forests suffered and shrank to an area of 8,373 km², of which 4,264 km² occur in India, and the rest in Bangladesh.
Of the 9,630 km2 of intertidal zone occurring in India, 5,366 km2 have been reclaimed. The water tables in the vicinity of these reclaimed areas contain saline water at an average depth of 3m, while the freshwater table lies at an average depth of 100m. As a result, only a single crop of low productivity is obtained annually. In addition, the problem of acid sulphur soil is quite acute in many places. Brackish water aquaculture has taken place at the expense of mangroves, and these areas are ultimately abandoned due to the acid soil problem, disease, etc. An area of about 3,500ha has been degraded within the reclaimed area to date. Within the mangrove forests, the pressure of an increasing population coupled with natural geomorphic stress caused by the neo-tectonic tilting of the Bengal basin has given rise to degraded mangrove areas, estimated to be around 22,500ha.
The Sunderbans serves many important functions in India, namely, 1) as a nursery habitat for a large range of aquatic life, and the subsequent source of coastal fisheries in Eastern India; 2) as natural traps for sediments carried down the Ganges; 3) as buffers receiving a huge nutrient load of 750 million l/day from Calcutta, and the River Ganges; 4) as natural shelters for the metropolis of the Calcutta suburbs, particularly during the annual high gales of the Bay of Bengal. The Sunderbans contains 37 species of 'obligate' mangrove plants stretched over an area of 2,200 km2, the largest diversity of mangrove plants on the Globe. This is also the only mangrove area on earth that is inhabited by tigers. In addition, it also contains 127 species of euryhaline fish, a total of 1287 animal species comprising 873 invertebrates, one species of Hemichordata, and 413 species of vertebrates. Owing to the rich species diversity present, the Sunderbans therefore deserves resuscitation, particularly of its degraded mangrove areas.
To date, the following measures have been adopted to restore the degraded mangrove areas of the Indian Sunderbans:
During the preparation of the coastal zone management plan of the West Bengal area, the dynamics of mangrove degradation was studied. A comparison of data from1989 and 1995 indicated that there was practically no increase in total mangrove area, but a net increase of density in mangrove vegetation by 110ha. In these 5 years, attempts have been made to artificially plant up to 9,050ha of mangroves in barren reclaimed areas. However, the success rate was only 1.52%.
Brian R. Crawford1, Audrie J. Siahainenia1, Ferdinand Pua2 and Christovel Rotinsulu1
1 Coastal Resources Management Project, Jalan Wolter Monginsidi No. 5, Manado, INDONESIA. (Coastal Resources Center, University of Rhode Island, U.S.A.)
2 Natural Resources and Environment, Regional Development Planning Board, North Sulawesi, INDONESIA
The United States Agency for International Development in cooperation with the Government of Indonesia started an initiative in North Sulawesi in 1997 which aims to strengthen decentralized and participatory coastal resources management. One goal of the project is to develop community-based coastal management models which can eventually be adapted more widely to other coastal villages in the Province, as well as within Indonesia. Three field sites have been selected in the province for intensive implementation activities. One site, consisting of the two villages of Bentenan and Tumbak located on the East coast of the Minahasa District and bordering on the Maluku Sea, exhibits several examples of destructive and unsustainable fishing and coastal resource use patterns found elsewhere in the Southeast Asian region, including Indonesia. Bomb fishing, seaweed farming above and near patch reefs, use of fine meshed nets for collection of milkfish fry, use of FADs for seasonal harvest of pelagic species in spawning aggregates, harvest of mangroves, capture of several rare and endangered species of marine animals, a growing local tourism industry, among other issues, have all raised concerns about the long term sustainability of these coastal ecosystems to provide livelihoods to the coastal residents. While many of the coastal ecosystems adjacent to these communities are still in good condition, evidence of degradation and trends towards increasing degradation and over-harvesting are present. The Coastal Resources management Project is attempting to slow, stop or reverse this degradation, while at the same time sustaining or improving the quality of life of coastal residents, through community-based planning and implementation strategies that have been applied successfully in others areas of the Asian region. A soft approach to rehabilitation (non-engineering) by transforming current unsustainable and destructive use practices into more sustainable forms of development is the primary emphasis of the project at this field site. Public education activities, community-based monitoring and enforcement, formation of local marine resource management committees and the development of village-level ordinances, among other things, will be implemented to encourage changes in the values and behaviour of local residents in the exploitation of resources. If destructive and unsustainable practices are abandoned, the ecosystems may likely be rehabilitated through natural regeneration, since they are still in relatively good condition. This is considered the most cost-effective solution. A significant design feature of this project is the application of a practical but systematic monitoring program at the project site and at nearby control sites, to determine the impacts of project interventions on environmental quality and quality of life of the coastal community over time. A management-driven research agenda is also being prepared to better understand the ecological and socio-economic underpinnings of the local issues. In addition, strategies for documentation, dissemination and adoption of successful approaches to other coastal communities are described so the project can have a cost-effective and lasting impact on progress towards more sustainable forms of coastal management in North Sulawesi and Indonesia.
Agustinus M. Samosir
Department of Natural and Rural System Management, University of Queensland, Lawes, QLD 4343, AUSTRALIA
The recent 'collapse' of the shrimp aquaculture industry in Indonesia has been a 'blessing in disguise', and has made way for the restoration and proper management of coastal resources. The Madura Strait along the east coast of Java contains complex mangrove and aquaculture areas, and provides an example of how traditional activities which have been carried out for more than five hundred years have suffered from modern environmental destruction. Although limited numbers of 'tambak' farmers have managed to survive, most have abandoned their ponds mainly due to the toxic cocktail of biological and chemical waste from intensive shrimp ponds and other coastal activities nearby. This paper examines the feasibility of rehabilitating more than 40,000 ha of mangrove and aquaculture areas, and especially focuses on the mitigation of water quality degradation. Integrated mangrove and aquaculture pond management in six 'green' and 'brown' villages are reviewed to establish the effectiveness of rehabilitation programmes in these areas. This will enable a proper assessment to be carried out on the effectiveness of community based strategies to restore the condition of the coastal plain.
A.Dikou1, and T.Toma2
1 Marine Science Department, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-01, JAPAN
2 Information Engineering Department, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-01, JAPAN
Since the late 1960's an unprecedented increase in sedimentation outflow (namely red-soil pollution) has occurred on Okinawa Island, Japan. This paper aims at: 1) Presenting the agents causing the red-soil pollution, the impacts and results of monitoring the pollution; and 2) Presenting and evaluating the administrative and technical measures taken against red-soil pollution. The main agents of red-soil pollution on Okinawa can be divided into natural and anthropogenic ones. Natural factors are affected by the nature of: i) the soil, i.e. low permeability and mainly composed of fine particles; ii) the terrestrial area, i.e. proximity of mountains to the shore, and comparatively small rivers facilitating quick discharge of red soil to the sea; and iii) the geomorphology of the sea, i.e. the "closed" sea around Okinawa island inhibits dilution of red-soil and facilitates its settlement near the shore. On the other hand, the main anthropogenic factors include: i) the extension of the agricultural zone, ii) the increase in construction activities, e.g. dams, roads, tourist facilities, and iii) military activities. Red-soil pollution has had adverse effects on fringing coral reef ecosystems around Okinawa, fisheries, aquaculture, the tourism industry, and underground water resources.
The Okinawa Prefectural Institute of Health and Environment has adopted an innovative monitoring method for the content of red soil in benthic samples. It measures the weight of suspended particles in kilograms (kg) contained in one cubic meter (m3) of sea sediment, to obtain an index of red-soil pollution. From 1983 to 1991, 560 sites all over Okinawa were repeatedly sampled annually to obtain a status of red-soil pollution along the coasts. The reports indicate that the red-soil content in benthic samples has dramatically decreased, mainly due to the application of mitigation measures and improved environmental politics. The main mitigation measures applied to prevent red-soil outflow include the use of sand-catch ponds, mulching, and contour farming. However, these measures have proven to be inadequate, and cost-ineffective in many cases, e.g. sand-catch ponds were helpful in preventing accumulation of coarse particles but not the outflow of fine ones, and mulching is too expensive for individual farmers, necessitating governmental funding of cooperatives.
Administrative measures against red-soil erosion from farmland development utilised preventive standards originally set for mainland Japan. However, the standards were inappropriate because of differences in climate, topography, and soil characteristics between Okinawa and mainland Japan. In addition, environmental impact assessments (EIAs) of potential development projects are still in rudimentary stages and have not yet yielded satisfactory results. Although the Okinawa Prefecture recently implemented a red-soil prevention ordinance for construction projects, this ordinance acts more as a guide for construction projects than as a law, since neither penalties nor rewards are mentioned. Prefectural research on the status of red-soil pollution and impacts on ecosystems is in the data accumulation stage, and collaboration between various, pertinent sectors is essential. A coastal zone management plan which would integrate the pertinent prefectural offices, researchers, users and an environmentally-aware Okinawan community is needed in order for the problem of red-soil pollution in Okinawa be managed sustainably.
Aileen S.H. Tan and Zulfigar B. Yasin
Muka Head Marine Research Station, Centre for Marine and Coastal Studies, Universiti Sains Malaysia, 11800 Penang, MALAYSIA
Giant clams in Malaysia are only found in limited areas in the South China Sea. Five species of Tridacnidae have been recorded: Tridacna gigas, T. maxima, T. squamosa, T. crocea and Hippopus hippopus. Of the five species, only T. crocea occurs in some numbers, T. gigas is virtually extinct, while the other three are endangered. Therefore, the depleted reefs in Malaysia need to be restocked with giant clams for conservation purposes. Local institutions and organisations, with the help of the Fisheries Department, can promote clam conservation, not only by restocking reefs and introducing regulations on giant clam collection, but also by stimulating the establishment of community resource management schemes based on the rich tradition of customary marine tenure found in the country. This paper will discuss the present and alternative methods of giant clam conservation in Malaysia.
Zulfigar B. Yasin, Aileen S.H. Tan and Anisah Lee Bt. Abdullah
Muka Head Marine Research Station, Centre for Marine and Coastal Studies, Universiti Sains Malaysia, 11800 Penang, MALAYSIA
The diversity of corals on Malaysia's reefs is among the highest in the world. More than 70 genera of scleractinians are found in Malaysian waters and most of these are located in the South China and Sulu Seas. The depth range of these corals are between 2-7m in the Straits of Malacca, to more than 35m in the Sulu Sea. This is reflective of the water turbidity in the respective waters.
Of the fourteen groups of islands in Malaysia, more than half have areas designated as Marine Parks or Marine Reserves. Most of these are on the east coast of Peninsula Malaysia where they enjoy legal protection. These islands that are protected also represent areas with better reefs.
Issues faced by reef conservationists in Peninsula Malaysia are different, compared with East Malaysia. The biggest threat to coral reefs located in Peninsula Malaysia is sedimentation due to coastal development, tourism activity in coastal areas and trawling. In East Malaysia, the threats are from increased tourism pressure and destructive fishing (fish bombing and poisoning). On reefs that are further from the mainland, lack of enforcement becomes an issue. This has arisen from the lack of manpower within the enforcement agency. This paper discusses what attempts have been made to overcome this issue, by the introduction of community-based reef conservation and management.