This paper reviews the various researches on tilapia at the BAC with the purpose of disseminating the information so far generated and identifying the gaps in tilapia research under saline conditions. Primary studies on tilapia at BAC were concentrated on increasing production of tilapia in brackishwater ponds and how this targetted production could be obtained more effectively and efficiently. Monoculture and polyculture procedures for tilapias including fertilization and feeding were studied. Forage fish: carnivore fish ratios were established for certain species which could be effective in thinning down the population of young tilapia while allowing the original stocks to grow bigger and at the same time producing fingerlings for restocking. This paper presents the results of various studies on tilapia.

Increased tilapia production can be attained in several ways. It can be achieved through development of better diets, proper stocking densities, increasing cultural inputs, efficient management practices, etc. but yields cannot be optimized if genetically inferior species are used. The continued use of deteriorated stocks of tilapia (i.e. Tilapia nilotica) is a deterring factor in the expansion of the tilapia industry (PCARRD, 1985).

The Anatidae Family consists of ducks, geese and swans. These birds are one of the groups of waterbirds that are ecologically dependent on wetlands*, at least at some parts of their life cycle. Anatidae species and their habitats provide social, cultural, economic, and scientific benefits to human life. Wetlands and associated upland habitats are one of the world s most highly productive environments with wide biological diversity. Many populations of the Anatidae species are migratory. The typical migrations of Anatidae are populations breeding in the Arctic or northern temperate regions and wintering in temperate and tropical zones. During their migration, they regularly cross international borders of several countries and territories. Many tropical species are sedentary while others mainly have seasonal movements related to the occurrence of rains and the temporary flooding of wetlands. Almost all Anatidae species are temporarily flightless during the moult of their flight feathers after breeding, and many species make moult migration to the safe moulting grounds. Thus, the conservation of these populations and their habitats requires cooperation at the regional and international levels. The Anatidae Site Network is a cooperative international program with key sites of international importance to the Anatidae populations in the East Asian Flyway (migration route). Its goal is to ensure the long-term conservation of migratory Anatidae populations through recognition and appropriate management of a network of sites of international importance. It is a network of both sites and people. It encourages site management bodies and/or organizations relevant to the management of the site to promote appropriate management of the site through development of a site management plan and other conservation measures. It also promotes the local recognition of the importance of the site for the conservation of Anatidae populations through awareness and educational programs. The Site Network is being coordinated by Wetlands International under the Asia-Pacific Waterbird Conservation Strategy. Key sites of international importance to Anatidae populations are those that:

• regularly support > 20,000 migratory Anatidae populations;
• regularly support > 1% of the individuals in population of one migratory species or subspecies in the family Anatidae; or,
• support appreciable numbers of a migratory Anatidae population with unfavorable conservation status.

The Philippines has no natural populations of geese and swans. Only ducks species are recorded in the country - one endemic species (Anas luzonica), two resident species (Dendrocygna arcuata and Dendrocygna guttata) and 15 migratory species. Naujan Lake National Park in Mindoro Oriental, Philippines is the fifth largest lake and, at present, the only designated Anatidae Site Network in the Philippines. It has an area of 14,567 ha: 8,125 ha of open water; 1,412 ha of marshland; and 5,030 ha of terrestrial catchment. Three species of ducks are recorded in the area: Anas luzonica, Aythya fuligula and Dendrocygna arcuata. Aythya fuligula, a migratory species, has a biogeographical population in the East Asia Fly way of 500,000-1,000,000. Naujan Lake National Park supports an average of 11,000 individuals of Aythya which is estimated >1% of its bio-geographical population. The Lake is also a Ramsar Site (wetlands of international importance). The site management authority is the Regional Executive Director, Department of Environment and Natural Resources-Region IV, 1515 L&S Bldg., Roxas Blvd., Ermita, Manila. Tel: (+63-2) 5212064, Fax: (+63-2) 5212253. If you are aware of areas with large number of ducks, please contact Marlynn M. Mendoza of the Protected Areas and Wildlife Bureau (PAWB). Telefax: (+63-2) 9258950, Email: mmendoza@i-manila.com.

Lake Leonard is a potential ecotourism destination still unknown to many. It is located within the hinterlands of Maco, Compostela Valley Province (formerly part of Davao del Norte), Philippines. The lake was formerly utilized as tailing pond of mine waste generated by North Davao Mining Company from 1984 to 1992 and fortunately, its operations were stopped due to financial problems. In 1997, the Provincial Mining Regulatory Board recognized the lake s ecological importance and recommended for its establishment as a Protected Area under the National Integrated Protected Areas System (NIPAS). The Department of Environment and Natural Resources (DENR) conducted initial studies and among the results were: 1. Water analysis revealed that the lake falls under Class B, recreational water for bathing, swimming and skin diving. 2. Protected Area Suitability Assessment (PASA) showed, among others, that there are few inhabitants and it is surrounded by adequately-stocked dipterocarp forest. Biodiversity is high as shown by the presence of varied species of flora and fauna. The establishment of the lake and its environs as a protected area is imperative considering its unique biological and physical features. Likewise, it would contribute in the global effort towards biological diversity conservation and sustainable development.

This paper presents the successful partnership of the Buhi local government, the San Ramon Barangay Council and its residents, and the Bicol University for successfully reviving the stock of sinarapan (Mistichthys luzonensis Smith), through the Sinarapan Re-population Strategy (SRS), implemented in two mountain lakes in Buhi, Camarines Sur, Philippines. Given the very low population of the small fish in Lakes Buhi and Bato, where the fish was very abundant in the 1940s to the 1960s, developing the SRS is the direct approach to revive the stock of the world s smallest commercial fish . It has faced the problem of declining stock with a logical and immediate solution through a natural experiment . Sinarapan stock revival through the SRS exemplifies adequately practical use of scientific information for biodiversity conservation and comanagement. SRS is the only fish translocation strategy in mountain lake conditions in Asia. Success with the SRS is a vital prerequisite to the goal of reviving the sinarapan in Bicol s major lakes where the fish supported major fisheries and gave fame to the region. Experiences in implementing the SRS confirmed that natural science should agreeably blend with rural sociology towards the aim of successful biodiversity conservation. Local government support and active community participation are indispensable to effective biodiversity protection and management. Pro-active information dissemination mechanisms to local government councils were a key strategy for enjoining their cooperation for conservation.

Lake Buhi is a multi-species fishery resource and known worldwide for being the home of the world s smallest commercial fish (Mistichthys luzonensis). The lake is used for fishery, agriculture, irrigation, hydroelectric power, navigation, and domestic purposes. Any particular use of the lake s resource system will have beneficial or adverse effect to its immediate environment. Man-made intervention such as unregulated fish cages, unsound farming system practices, establishment of control structure for irrigation and the hydroelectric power plant, and improper waste disposal alter the ecosystem. Ecological imbalance has serious consequences for it affects the entire lake. The occurrence of massive fish kill in Lake Buhi is due to depletion of oxygen. Values dropped from 0.05 to 1.0 mg/L, which is lethal to the fish. This is brought about by the upwelling of accumulated organic pollutants from the lake bottom: (detritus and domestic waste, decaying unused feeds, fish excretes accumulated by overstocked tilapia in cages), the proliferation of water hyacinths, and fluctuating water level. These resulted to the formation of ammonia (NH₃), carbon dioxide (CO₂), and hydrogen sulfide (H₂S) that have exceeded the tolerable level for fish life. These factors caused high temperature (29°-30°C), enhanced respiration of aquatic life, and decreased the solubility of oxygen. Likewise, increased bottom sediments (2.3 - 3.0 m) and very low transparency (0.82m) that block the penetration of sunlight and hinder photosynthetic activity in the water were recorded. The inequitable access and use of fishery resource are the major problems that beset the lake. There is a need for sound fishery management and regulatory intervention to help resolve the problems affecting the productivity and stability of the lake s ecosystem.

Laguna de Bay is the largest inland body of water in the Philippines and one of the largest lakes in Southeast Asia. The lake and its watershed, technically referred to as the Laguna de Bay Region or Basin, encompasses the provinces of Rizal and Laguna, portions of Cavite, Batangas and Quezon and a large portion of Metro Manila. It is a host to a total of 66 local government units (LGUs) (49 municipalities, 12 cities and five provinces) and is home to over 10 million people. Over recent decades, uncontrolled population growth, indiscriminate deforestation and land conversion, intense fisheries, widespread industrialization, and urban sprawl have produced massive changes in the Laguna de Bay and its watershed. The resulting problems relate to solid waste management, sanitation and public health, congestion, sedimentation, unmitigated input of domestic, agricultural and industrial wastes, deteriorating water quality, flooding problems, and loss of biodiversity. The task of turning the tide of environmental degradation and of protecting and conserving the lake and its watershed for posterity calls immediate and decisive action. Using the so-called Integrated or Basin Approach to water resources management, the Laguna Lake Development Authority (LLDA) has initiated a number of innovative actions that could spell the difference in the effort to save Laguna de Bay. These include: a) the Environmental User Fee System (EUF), a market-based instrument designed to motivate polluters to comply with effluent standards; b) Zoning and Management Plan (ZOMAP) for fish pens and fish cages; c) Shore Land Development and Management Plan (SMDP); and d) the River Rehabilitation Program. The module for River Rehabilitation developed over seven years has produced a model for multistakeholder and community participation and involvement in the task of resource conservation and management which is gaining recognition internationally.

Some 75,000 pieces of live sinarapan (Mistichthys luzonensis) individuals were transferred to mountain Lake Makuwaw in San Ramon, Buhi, Camarines Sur in January to May 2001. Before the fish transfers, the lake was chosen from among four mountain lakes evaluated for their suitability for the fish. Five months before the direct live fish transfers, regular monthly seinings in the lake were done using fine-mesh push-net. No sinarapan or similar-looking small goby was found. This confirmatory survey was vital in evaluating the re-population strategy because it was ascertained that the new stock came from individuals stocked during the fish transfer activities. About 30-70% of the fish died during transport and until a day after each stocking of 15,000 per batch (with four batches a month). The minimum viable fish transfer quantity of 10,000 to 15,000 was estimated based from information on the population dynamics of the fish. Viable stock of the fish in the lake has thrived, matured, and bred as evidenced by live juvenile and gravid adult sinarapan sampled starting July 2001. Morphometrics and biological characteristics of the Makuwaw stock do not differ significantly (a=0.05) with those of the stock from Lake Manapao where the live sinarapan translocated were taken. From knowledge of the population dynamics and aspects of the reproductive biology of the fish, the change in the fish population in the lakes was quantified. Population analyses showed that the role of natural mortality is primary and critical to re-population success. Natural mortality is 95% and 99% for six-month and 12-month periods, respectively. Given the goby s high natural mortality, absence of pre- and post-hatching parental care, and the general vulnerability of eggs to environmental factors, the key biological determinants to successful re-population of the species are stocking at its viable quantity and meeting the basic life requirements of the fish. The social dimension related to community support and participation to strengthen network of protection for the sanctuaries is equally vital to sustain re-population efforts.

The Philippines is endowed with more than 200 lakes that are abundant in water, fisheries and other resources. With the exception of five major lakes (Laguna de Bay, Lake Lanao, Lake Taal, Lake Naujan and Lake Buhi), there is little or no information on resources management of other lakes in the country. The main issues and problems identified regarding lake resources management are the decline in their fisheries production and loss of biodiversity due to overfishing, destruction of habitat, pollution, introduction of exotic species and multiple-use conflicts. These challenges need an effective management framework, a national management plan for lakes with the ecosystems or integrated approach for their sustainable development and the capability-building of local government units (LGUs) and other institutions for lake management. The lessons learned from the management of the Laguna de Bay by the Laguna Lake Development Authority (LLDA), the Master Plan for Lake Taal, and the case studies of Lake Buhi for the sinarapan, and the cyprinids of Lake Lanao will be highlighted.