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.
A mass-balance steady-state trophic model of the coastal fisheries ecosystem off the West Coasts of Sabah and Sarawak, Malaysia (10 - 60 m depth) was constructed using the Ecopath software. The ecosystem models were partitioned into 29 ecological/trophic groups. The input values (e.g. biomasses) for selected groups were obtained from the research (trawl) surveys conducted in the area in 1972. The estimated mean trophic level of the fisheries catch for both models is about 3.3.
The biomass of 40 ecological groups, the diet composition of prey and predators, production/biomass (P/B) and consumption/biomass (Q/B) ratios, and catches were used as basic input to parameterize an Ecopath model of the Gulf of Thailand. Following construction of a mass-balance ecosystem model, a time-dynamic simulation model (Ecosim) was used to simulate the impact of change in fishing effort. This was done using time series data to validate the historic fisheries development in the Gulf of Thailand prior to using the model for forward-looking simulations.
Aquatic agricultural systems in developing countries face increasing competition from multiple stakeholders operating from local to national and regional scales over rights to access and use natural resources—land, water, wetlands, and fisheries—essential to rural livelihoods. A key implication is the need to strengthen governance to enable equitable decision-making amidst such competition, building capacities for resilience and transformations that reduce poverty.
Indonesia’s fisheries exports rose from 2 206 t in 1970 to 598 385 t in 1996 with a subsequent export value rise from US$0.69 billion to US$1.78 billion. The surplus in the balance of trade (BOT) was US$1.59 billion in 1996. The fisheries exports were predominantly shrimp, tuna, skipjack and demersal fishes. Large scale fisheries operations are prevalent in the Java Sea. The dominant fishing gear is hook-and-line (40%), gillnet (31%), traps (10%), seine net and lift-net (6%), purse seine (1%), shrimp net with BED (0.04%) and others (6%). The large scale fisheries e.g.
Sri Lanka is an island country with a land area of 65 610 km2. With the declaration of the exclusive economic zone (EEZ) in 1976, the country gained sovereign rights over an ocean area of 536 000 km2 and EEZ extending from 24 to 200 nm. The continental shelf is about 26 000 km2 with an average width of around 22 km, and the coastline is 1 100 km long. The total annual fish production of Sri Lanka was 25 000 t in 1952 and 269 850 t in 1998. Major fish species caught in Sri Lankan waters are skipjack, blood fish, yellow fin tuna, mullet, shark, trevally, Spanish mackerel, prawns, lobsters.
Fisheries are an important source of protein and employment for Sri Lanka’s population. The declaration of the Exclusive Economic Zone (EEZ) in 1976 gave the country a water area larger than its land area. The coastal fisheries resources consist of small and large pelagic fish, demersal and coral reef fish, invertebrates, shrimps and crabs. The small pelagic fish contribute 70% of the catch from coastal waters with an estimated annual production of 152 752 t in 1997.
India is endowed with a continental shelf of 0.5 million km2 and an exclusive economic zone (EEZ) of about 2 million km2. Almost half (39%) of the Indian population utilizes the marine fisheries resources. India ranked sixth worldwide in total fish production (4.95 million t) and second in inland fish production (2.24 million t) during 1995 - 96. Fish production expanded from 0.75 million t in 1950 - 51 to 4.95 million t in 1995 - 96, giving a significant increase at a cumulative growth rate of 4.2% per annum.
The marine fisheries sector in Malaysia contributes significantly to the national economy in terms of income, foreign exchange and employment. In 1999, marine fisheries contributed 1.245 million t (90% of total fish production) valued at US$1.18 billion. The total value accounted for about 1.53% of national GDP and 11.31% of agricultural GDP. The export of fish and fishery products amounted to about US$210 million. The sector provided employment to about 80 000 fishers. Fisheries management is currently guided by the Third National Agricultural Policy (NAP3 1998 - 2010).
A preliminary mass-balance trophic model was constructed for the coastal fisheries ecosystem of the West Coast of Peninsular Malaysia (0 - 120 m depth). The ecosystem was partitioned into 15 trophic groups, and biomasses for selected groups were obtained from research (trawl) surveys conducted in the area in 1987 and 1991. Trophic interactions of the groups are presented. The network analysis indicates that fishing fleets for demersal fishes and prawns have a major direct or indirect impact on most high-trophic level groups in the ecosystem.