After commencing with a summary of the current status, importance and productivity of natural wetlands, the chapter reviews the contribution of wetland ecological functions to sustaining vital ecosystem services. Wetlands are vulnerable to a range of anthropogenic pressures, notably land use change, disruption to regional hydrological regimes as a result of abstraction and impoundment, pollution and excessive nutrient loading, the introduction of invasive species and overexploitation of biomass, plants and animals.
Settlement ponds are used to remove particulate and dissolved nutrients in Australian land-based aquaculture wastewater. At best, marine and brackish water settlement ponds reduce total suspended solids by 60%, but their efficiency is inconsistent. Functional improvements to nutrient removal systems are essential to provide uniform and predictable treatment of flow-through aquaculture wastewater. Furthermore, environmental regulation of discharge from intensive systems in Australia is increasing, providing the impetus to upgrade rudimentary single-step settlement pond systems.
This paper deals with a number of case studies that were undertaken during the last 8- 10 years in utilizing divergent ‘Tal’ wetland ecosystems (deep, semi-deep, temporary in a range of agro-ecological zones like NAZ, OAZ and Coastal Zone of the region) for the development of integrated management programmes using a range of approaches.
A method of consensus building for management of wetlands and fisheries using a systematic approach to participatory planning and initially developed in Bangladesh is now being applied in both Bangladesh and the Mekong delta. The method recognizes diversity in livelihoods and works through a structured learning and planning process that focuses on common interests. It works with each category of stakeholder separately to prioritize the natural resource problems that their livelihoods are largely dependent on; they then share and agree common priorities in plenary.
Commencing with a summary of the current status, importance and productivity of natural wetlands the contribution of wetland ecological functions to sustaining vital ecosystem services is then reviewed. Provisioning services, notably fish and water for irrigation or domestic and industrial purposes constitute important benefits derived by humanity from wetlands, whilst recognition is growing that supporting, regulating and cultural services supported by wetlands are critical for sustaining social-economic systems and ensuring human well-being.
Bangladesh is rich in aquatic resources with extensive seasonal and perennial water bodies throughout the country. In the past, the expansive floodplains, oxbow lakes, beels, and haors were home to a vast range of fish species. Of the 260 fishes found in the inland waters of Bangladesh, 150 grow to a small size (maximum length of about 25 cm), and these are found in the wetlands.
Rural households who fail to gain a voice in decisions over the management of shared forests, pasturelands, wetlands and fisheries face heightened risks to their livelihoods, particularly as competition increases between existing and new user groups. Exclusion from decision-making increases vulnerability of rural households, making it more difficult for them to move out of poverty and thwarting broader efforts to achieve sustainable resource management. Poor rural women in particular often face institutionalized barriers to effective participation in resource management.
Small indigenous fish species (SIS) are an important source of essential macro- and micronutrients that can play an important role in the elimination of malnutrition and micronutrient deficiencies in the populations of many South and Southeast Asian countries. Of the 260 freshwater fish species in Bangladesh, more than 140 are classified as SIS and are an integral part of the rural Bangladeshi diet. As many SIS are eaten whole, with organs and bones, they contain high amounts of vitamins and minerals, including calcium, and iron and zinc. Some SIS, such as mola, are also rich in vitamin A.
Small fish are a common food and an integral part of the everyday carbohydraterich diets of many population groups in poor countries. These populations also suffer from undernutrition, including micronutrient deficiencies – the hidden hunger. Small fish species, as well as the little oil, vegetables and spices with which they are cooked enhance diet diversity. Small fish are a rich source of animal protein, essential fatty acids, vitamins and minerals.
Cambodia's wetlands cover over 30 percent of the country’s land area and support one of the largest, most diverse and intensive freshwater fisheries in the world. In the flood season (July-February), the flood waters from the Mekong River and Tonle Sap Lake catchments create a vast open water system on Cambodia’s lowlands. During this period, inundated rice fields become open access fishing grounds for local villagers and migrant fishers.