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Asia-Pacific represents the most important region for fisheries and aquaculture production. It is world's largest contributor to the world's aquaculture, producing 46.9 million tons or 91% of the global aquaculture production (FAO, 2005). The growth of aquaculture production has been very strong for the last ten years due to the increased production from China. The aquaculture production in Southeast Asia is diversified comprising 41.6% freshwater fish, 23.5% of aquatic plants, 6.7% crustaceans, 7.3% marine/diadromous fish and 21.1% of mollusks. The Philippines consists of 7,107 islands and islets which has rich in marine and inland resources. In terms of coastline resources, Philippines ranked the fifth longest coastline worldwide having 36, 289 kms. in length. The Philippine coastal zone is typical of tropical coasts with five major resource units occurring along its shallow coastlines, i.e. coral reefs, mangrove ecosystems, beach systems, estuaries and lagoons. The linkage between the upland and coastal ecosystems is considered very important ecologically, therefore it is emphasized that Coastal Resources Management (CRM) should not be limited to only the coastal zone. The vast water resources allow Philippines to continue expanding its aquaculture production. However, this should be done in sustainable manner. In the Philippines, fisheries and aquaculture are an important part of the Philippines' economy: growing rapidly, providing export income, providing rural employment and sustenance for poor people. Agriculture and fisheries account to about a fifth of the total economy and based on statistics, it employs a total of 10M people, nearly 40% of the labor force (BFAR, 2006). Agriculture-based communities are host to most of the poor in the country. Further, large increases of wild fisheries sector are unlikely due to limited resources. In contrast, aquaculture is still expanding rapidly and the long coastline with sheltered area provides opportunities for expansion. For aquaculture to be sustainable there must be planned development to ensure that production is within the carrying capacity of the waters and that the environmental impacts mitigated. Aquaculture-related policy and legislations in the Philippines: The last decade of 19th century saw a major paradigm shifts towards conservation and management versus expansion and exploitation and sustainability over expanded production (Lopez, 2004). It was also in 1980s when decentralization of national policies and implementation of policies were devolved to local government units (LGUs) when Republic Act (RA) 7140 was enacted and came to force. This Law was followed with the issuance of RA 8435, otherwise known as Agriculture and Fisheries Modernization Act of 1997 (AFMA) which provides for the maximized and sustained utilization of production area towards local industrialization. The promulgation and approval of RA 8550 (Fisheries Code of 1998) likewise is a significant milestone of the decade. The legislation provides the policy, legal and institutional framework for sustainable use of the fisheries resources with the long term goal of ensuring that the fisheries sector objectives can be attained. Another equally important legislation is the National Integrated Protected Areas System (NIPAS) Act of 1992 otherwise known as RA 7586. The law provides for the establishment of protected areas with natural biological and physical diversities of the environment particularly, those with biological features to sustain human life and development as well as plant and animal life. These include all areas of lands declared as parks, sanctuaries and refuges, reserves, landmarks, protected landscapes and seascapes, virgin forests and watersheds existing as of 1993 and other areas as may be declared under the Law. Environmental impact of aquaculture: Like many other human activities, aquaculture produces wastes which, if not properly managed, may negatively affect the environment. Over the past decades, aquaculture industry has experienced considerable expansion with attention being paid subsequently to the environmental effects. The potential impacts of aquaculture are wide-ranging from pollution problems, fish kills and eutrophication, most especially in enclosed waters with poor water exchange rates. The increase in nitrogen and phosphorus from aquaculture activities results to eutrophication, oxygen depletion and consequently fish kills. Marine aquaculture operations and their associated infrastructure can disturb scenic rural areas. Fish production generate effluent (e.g. waste feed and faeces, together with associated by product such as pesticides) which can have unacceptable impacts on the environment. There are also unwanted effects on wild populations, such as genetic disturbance and disease transfer by escapes or ingestion of contaminated waste. Aquaculture impact in the Philippines: Brackishwater Aquaculture: Most brackishwater aquaculture activities in the Philippines were developed on mangrove swamps. Some 400,000 has. of mangrove forests, less than half remains untouched. Most mangroves swamps were developed into fishponds which were converted into shrimp ponds. Fishpond developers clear-cut the mangrove area even up to the water edge disregarding and violating the regulations requiring at least 50 meters of mangrove to remain uncut. The clearing of forested mangrove area has decreased greatly in the Philippines from an estimated coverage of 450,000 ha in 1918 to less than 248,813 ha in December 2003. The most rapid decrease in mangrove coverage was during the 1960s-1970s when national policies encouraged the expansion of aquaculture. Today, fishponds cover about 289,000 ha, most of which were formerly mangroves. It is worthwhile to note that the mangrove forest which is the interface between the land and the sea recognized as a rich nursery ground for various marine species. Freshwater Fishponds: Freshwater fishpond operation as practiced in the Philippines is not known to have had any adverse environmental impact. Production is very extensive and semi intensive systems. Wastewater should not pose any problem, if this is used to irrigate croplands instead of being discharged directly to a body of water. Fishpens: Fish pens and cages structures to contain the fish in a body of water potentially pose more negative effects to the environment. The cage and pen cultures affect water body in the following manner: •Take up space, thuscompeting with other users. •Alter flow regimes which govern transport of oxygen, sediment, plankton and fish larvae. •Sediment and water column impacts. A typical example is Laguna de Bay, Philippines during the early 1980s. The fishpens occupied 35,000 ha. of the lake's 90,000 ha. area. The total fishpen area slowly dropped over the years to reach only 4,425 ha. based on fishpen licensing records of LLDA (2002). This reduction has been due to increased eutrophication of the lake and rising number of fish kills. Fish Cages: The uncontrolled proliferation of fish cages in small lakes has affected the dissolved oxygen regime, water nutrient levels and growth of fish in the cages in lakes such as Taal Lake, Philippines. Thus, during some seasons low oxygen levels and algal blooms can result in massive fish mortality which has happened many times. The sea cages are also showing signs of environmental impact. Indiscriminate installation and operation has serious environmental consequences such as accumulation of organic matter on the seabed with later undergo anaerobic decomposition. The carrying capacity or the optimal area for fish cages in lake waters and coastal sea farming still remains to be studied. In 1993 to 1998, there was an increase production of Taal Lake from 13,778 MT to 40,263 MT specifically on aquaculture. The production increase has attracted more investors to engage in fish cage culture in the area resulting to the proliferation of fish cages at Pansipit River and Taal Lake. To attain maximum production rate, operators practiced high stocking density and intense feeding and as a result, fish kill occurrences were experienced in 1997 and in 2000. Because of the above incident, the lake-wide management plan for an integrated sustained aquaculture and fisheries based on scientific knowledge of the lake's carrying capacity was developed. To address the problem, the following management interventions were implemented in the lake in coordination with the Local Government Units, local communities and other stakeholders; 1. Conduct of research and development studies (fish kill investigation, feeds and feeding management of tilapia in the cages, isopod infestation of native freshwater fishes in the lake. 2. Strengthen the fisheries management councils in the area. 3. Advocacy and extension services to include water quality monitoring system, formulation of early warning systems and Information, Education and Communication. Considering that Taal Lake is a designated protected are under the Republic act 7586 otherwise known as the National Integrated Protected Area System Act of 1992, a holistic Management Plan for Taal Volcano Protected Landscape (TVPL) was developed based on the guidelines provided for in the Act, with the following components: 1. Water quality and health of the lake. 2. Aquatic living natural resources. 3. Terrestrial watershed components. 4. Disaster preparedness and management. 5. Population and socio-economics. 6. Research program and knowledge center. Recommendations: It is very clear that environmental issues are emerging with the expansion of aquaculture and fisheries in the Philippines. The increased occurrence of fish kills and the degradation of municipal fishing grounds caused a serious ecological problem. To address this challenge, government, industry and civil society worked together in the formulation and implementation of the management plan for sustainable aquaculture based on the rules and regulations already in place. In general, the management of aquaculture and fisheries should be undertake with an ecosystem approach based on their scientifically calculated carrying capacity based on appropriate regulations for management. Aquaculture development must be made within the carrying capacity of the environment so that it is sustainable. This requires good planning and management of development. It also requires coordinated management at the site level, using ecosystem-based management of the water resource. Monitoring impact of the environment is likewise required to ensure that it is not causing long-term change to the environment.
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