Aquaculture is the fastest food-producing sector. It is the farming of aquatic organisms, like crustaceans, fish, molluscs and plants. Culture of aquatic organisms, particularly shrimps, is usually done in earthen ponds with some intervention in the rearing process to enhance production. Some of these processes to increase production are pond preparation, regular stocking, feeding, and the use of probiotics and other chemicals to improve soil, water quality, shrimp growth and immunity against diseases. The long range effect of the use of probiotics and other chemicals on the environment and on shrimps is unknown. Despite the various inputs, diseases continue to plague the industry, which could be due to the deteriorating environmental conditions that cause stress in shrimps thus making them susceptible to infection. Furthermore, chemicals and nutrients from aquaculture may affect biodiversity of the receiving environment. Responsible aquaculture is a sustainable development approach that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. There should be a good balance between satisfying human needs while maintaining or enhancing the quality of the environment and conserving natural resources. Human health or food safety as well as economic efficiency and/or livelihood opportunities should be taken into consideration. Responsible shrimp culture through ecological approaches to improve environmental conditions is herewith described. Ecological approaches recognize the interactions between an aquaculture farm and the external environment, including environmental resources and local communities. Ecological approaches to improve environmental conditions identified from cross sectional, longitudinal and tank studies may be classified into culture systems and phases of pond production: pond preparation and rearing. Two culture systems are identified to improve water quality: 1) the use of the greenwater system, and 2) the presence of mangrove in the receiving environment. Among the pond preparation practices, sludge removal, crack drying of pond, and liming were identified. Toxic substances as well as organic matter, which provide nutrients necessary for the growth of microorganisms, are removed during sludge removal and crack drying of the pond sediment. Liming to pH 11 kills most harmful microorganisms including the white spot syndrome virus; it also kills unwanted species in the shrimp pond like fish and crabs. During the rearing phase, abundant supply of natural food, low stocking density, less input, addition of fermented Avicennia alba leaves, use of molasses and rest periods are some of the important farming practices that reduce risk of disease occurrence. Other reported practices are crop rotation, biofloc technology, aquaponics, and integrated multi trophic aquaculture.

Milkfish is an economically important fish cultured in many countries in Asia. In Thailand, milkfish culture has not been given much attention and has not as been developed as in the other Asian countries because in the past the farmers prefer to grow shrimps and other high value fishes. Nowadays, environmental changes and degradation can affect water resources as well as the important aquaculture species that thrive in them hence the Thai Department of Fisheries recognizes the importance of developing aquaculture that is environment-friendly. This includes milkfish in particular because milkfish meat tastes good, easy to manage on farm, grows rapidly and can be grown in sea water, brackish or even freshwater. Milkfish farming is a low cost operation because milkfish feed mainly on algae and organic matter and these are natural food produced from other types of aquaculture activities. Milkfish can therefore be co-cultured with other species and are capable of reducing the amount of organic material from the process of aquaculture before entering the environment. In 2002, milkfish was first bred successfully through hormone injection and later broodstock mated naturally in Thailand. At present, production of the 1-inch milkfish has reached 1,000,000 per year. The culture sites are in the southern and eastern parts of the country, in brackish and salty areas. Culture methods are either monoculture or polyculture with other species such as shrimp, mussel etc. Milkfish culture in reservoirs last from 6 to 12 months when fish size is about 500 g or two pieces to a kg. and the price is about 50 baht/ kg. On the other hand, milkfish that are 600-1,000 g can sell at 65-90 baht/kg. Apart from culture, processing as well as marketing promotion of milkfish has also started in Thailand. Milkfish processing training is being conducted at least 2 times a year. As for the marketing initiatives, there is a move for the milkfish to be declared the symbol of Prachuap Khiri Khan Province since it was here that the fish was first found naturally in Thailand. This, apart from the plan to promote milkfish in the festivals throughout the country. Although found promising, some problems in the Thai milkfish industry are also recognized. Such issues notwithstanding, the Thai Department of Fisheries is coming up with guidelines for milkfish aquaculture as it is optimistic that this commodity shall open the doors to a new alternative industry in Thailand.

Singapore is a small country state with a demographic profile of over 5 million in population. With limited land for agricultural purposes and sea space available for fish farming, Singapore depends heavily on importation of fresh seafood. Even so, Singapore has a small but thriving and increasingly important food fish farming industry which accounts for about 6% of local food fish consumption. The main bulk of local food fish production comes from coastal farming in floating netcages along the northern coast of Singapore. Popular species of marine food fish cultured include seabass, pompano, groupers, mullets and milkfish. There are also a few land-based fish farms culturing species like tilapia, marble goby and snakehead. The ornamental fish farming industry is concentrated mainly in Agrotechnology Parks and there are about 75 fish farms producing ornamental fishes with an approximate value of $76.7 million that is exported to over 80 countries. The Agri-Food and Veterinary Authority of Singapore (AVA) is the national authority for aquaculture development in Singapore and manages aquaculture farms through the issuance of fish farming licenses. For marine food fish farms, the farm licensee has to abide by good farm management guidelines to maintain the farm in good condition and ensure that the farm does not engage in activities that would impact the farming environment. For land-based farms, there are also guidelines that address infrastructure layout, farming system and water treatment facilities. The latter requires that sedimentation ponds, reservoir ponds/tanks, supply/drainage systems and trade effluent treatment plant are included in the farm set-up. There are several challenges and issues faced by the aquaculture industry in Singapore. One of these is the consistent supply of good quality fish fry as farmers have to source for fish fry from overseas sources that may not be consistent or readily available. Issues of fish health and farm management are other challenges faced by our fish farms. These factors affect farm productivity and the sustainability of farming operations. The AVA has established the Marine Aquaculture Centre (MAC) on St John's Island to address the needs of aquaculture development for Singapore through development of fish reproduction and seed production as well as large-scale fish farming technology. At present, the fish reproduction technology research work involves closing the reproductive cycles of key marine food fish species and also fry production at a commercial scale level. Closing the reproductive cycle will help to reduce the reliance on imported fry. Good quality brooders are selected, maintained and bred to produce quality fry, which would translate to better growth performance and shorter culture period. This, together with good farm management practices, will optimize the usage of fish feeds during the culture cycle. To fill the gap in production and supply of good quality fish seeds for local fish farms, AVA shares information on hatchery technology development with local commercial hatcheries. The AVA collaborates with research institutes and local fish farms in the development of vaccines to boost the survival rate of fish fry and fingerlings. This will improve survivability, thus increase the production of the farms and reduce the reliance on prophylactic drugs that may have negative consequences from prolonged use. The AVA also renders technical assistance to the farmers to formulate viable production plans to improve production. By leveraging on the use of technology and good farm practices, such as implementation of fish health, fish nutrition and feeding protocols, it is possible to reduce production costs and improve productivity. The introduction of the Good Aquaculture Practice scheme for food fish farming will help improve the standards of the local aquaculture industry and sustainability through responsible management practices.

The white spot syndrome virus (WSSV) remains to be the most widespread and devastating infectious agent that has hit particularly the marine shrimp aquaculture industry worldwide. To date, there are no known effective strategies that can combat WSSV infection. This study aimed to elucidate host-pathogen interaction through the functional study of host - gene. Utilizing RNA Interference, the function of contig23 (c23) in the shrimp genome, identified to have high homology with WSSVORF-325, was determined. Three set-ups were prepared for treatment of c23-, GFP-dsRNA, and PBS using Macrobrachium rosenbergii freshwater prawns. Each treatment group was challenged with WSSV and survival rate was recorded. C23-, and GFP-dsRNA injected prawns showed a significant survival rate of 100%, in contrast to 20% of the PBS injected prawns at 10 days post-infection (dpi). Results showed that injection of c23- and GFP-dsRNA prior to challenge with WSSV, delayed and reduced mortality in contrast to PBS-treated prawns, which showed high mortality. Gene expression analysis showed silencing of both WSSV and c23 at day 3 post-WSSV challenge. This study proved that c23-dsRNA has a protective effect on WSSVchallenged prawns and highlights its involvement in the infectivity of WSSV in M. rosenbergii.

Aquaculture is promoted for food security and poverty alleviation in developing countries. This study examines the socio-economic impact of aquaculture technologies extended to calamitystricken rural communities in Nueva Valencia, Guimaras, representing the marine water fishery and in Dumarao, Capiz, representing the inland freshwater fishery at west central Philippines. The adoption pathway employed in both sites was community-based and participatory. The survey was conducted among cooperators and non-cooperators, randomly selected in equal numbers in two sites with 60 respondents each per site using a pre-tested interview schedule. Results showed that aquaculture is an acceptable technology both for cooperators and noncooperators. The venture is a profitable business either done individually or collectively through an association, if managed properly. Milkfish cage culture, however, needs big capital that technology adoption among local fisherfolk (Guimaras) is limited. In contrast, tilapia cage culture enables small farmers/fishers in Dumarao to venture on their own. Dumarao growers were able to innovate using local materials like bamboo poles to make their cages afloat instead of drums or plastic containers as buoys. There were, however, environmental, technological and institutional issues deterring technology adoption in both sites. Climate change and institutional issues were the more prevalent concerns of Dumarao growers. The technological issues like fluctuating market price, cost of feeds, and fry supply were more enunciated in Guimaras.

The United States Soybean Export Council s (USSEC) Soy-In-Aquaculture (SIA) project in the Philippines introduced the Low Volume High Density (LVHD) cage culture production methodology in 2003. The aim of this technology is to maximize farmers profit, improve productivity, reduce feed conversion ratios (FCR) and limit environmental degradation. The Philippine fish farmers were very conservative and hesitant about adopting the USSEC SIA Low Volume High Density (LVHD) cage culture technology, particularly the new feeding techniques using extruded floating feeds. This conservative attitude was highlighted with different projects using Nile tilapia (Oreochromis niloticus), milkfish (Chanos chanos) and snubnose pompano (Trachinotus blochii) in USSEC SIA LVHD cage feeding demonstrations conducted in different commercial farms in the Philippines.

As aquaculture production of tropical fish and crustacean species becomes more intensified, practical diets need to be formulated to be cost effective and environment-friendly. Ingredients should be included to satisfy the nutrient requirements of the animal, promote optimal fish growth, and boost the income of small-scale farmers and commercial producers with minimal impacts to the surrounding environment. Feed formulation for sustainable aquaculture should aim at increasing aquaculture system performance and profitability, enhancing the animals disease resistance, increasing attractability, palatability, and digestibility of practical diets, and maintaining environmental quality through sound feeding management and good aquaculture practices. More vigorous research and development efforts need to be supported to generate feed technologies that will ensure a steady and reliable supply of safe and high quality aquaculture products to the public while preserving the environment.

Widespread interest in mud crab species is increasing because these are highly prized both in domestic and export markets. Among the three mud crab species commonly found in the Philippines, Scylla serrata, S. olivacea, and S. tranquebarica, S. serrata is preferred by farmers because it is larger and less aggressive than the other species. Likewise, S. serrata is the most widely distributed species in the Indo-west Pacific region. Hatchery-produced seedstock are presently used by some crab farmers in their grow-out operations. In the hatchery phase, feeding mud crab larvae with shrimp formulated diets and natural food was found to reduce the occurrence of molt death syndrome, one of the major problems in seed production. Larvae given 25% formulated diet (FD) + 75% natural food (NF; rotifers and Artemia) and 50% FD + 50% NF showed better performance than those larvae fed 100% FD, 100% NF and 75% FD + 25% NF indicating that usage of natural food, especially the expensive Artemia, can be reduced. Since the early crab instar (C) produced in the hatchery need to be grown further before stocking in grow-out ponds, two phases of nursery culture have been developed. C1-2 are grown to 1.5-2.0 cm carapace width (CW) size in the first phase and further grown to 3.0-4.0 cm CW in the second phase. Nursery rearing is done in net cages installed in ponds for easy retrieval. A combination of mussel or trash fish and formulated diet is used as feed. Domestication of the mud crab S. serrata as a prerequisite to selective breeding has been done at SEAFDEC/AQD. Likewise, defining criteria for the determination of quality of newly hatched zoeae for stocking in the hatchery was initiated. Newly hatched zoeae were subjected to starvation and stress test using formalin. Starvation failed to elicit responses that were significantly different between the good and poor quality larvae hence it is not suitable for larval quality evaluation. Based on three-year data, the formalin stress test gave mean cumulative mortalities of 2.38±0.32, 8.24±0.88, 20±1.58 in good quality larvae, and 43.74±2.39 while 22.93±4.19, 63.68±7.17, 84.29±3.88 and 97.65±1.06 for poor quality larvae at 0 (control), 20, 30 and 40 ppm formalin, respectively. As formalin level increased, cumulative larval mortality also increased regardless of the quality of the larvae. Formalin stress test proved to be a reliable method to determine whether a batch of newly hatched zoeae was of good or poor quality.

The basic procedures for producing marine fish fry in hatcheries developed for milkfish fry production nearly 3 decades ago are the basis of fry production systems for all other marine fish species that are now reared in hatcheries in the Philippines and other Southeast Asian countries. These include large-scale microalgae production in outdoor tanks, feeding of appropriate sized rotifer grown on microalgae such as Nannochlorum during the first feeding phase, and shifting to larger prey such as Artemia towards the latter stages of production. In recent years, the increasing demand for high-value species such as groupers, sea bass, red snapper, and pompano in both local and export markets has encouraged a number of hatcheries to produce fry to supply the requirements of fish cage farmers. Techniques are modified using information from research institutions and multi-national firms active in developing products and equipment to improve commercial production of these species. Larval feeds of appropriate sizes, forms and presentation for various larval stages incorporating essential nutrients, micronutrients, and feed stimulants are now available in the market. Diseases in marine fish hatcheries have become common occurrences such that various chemotherapeutants, vaccines, and immunostimulants are now available and increasingly being applied in fish hatcheries. Technological developments in hatchery systems, such as the use of recirculating systems, water pretreatment protocols (ozonation, mircrofiltration, UV light treatment) are also increasingly being adopted by commercial establishments. A critical link between fry production and production of marketable fish is fingerling/ juvenile production in nurseries. Fry are commonly grown in brackishwater fishponds to appropriate size for stocking in fish cages. Methods to improve growth through proper feeding and nutrition, eliminate or reduce disease occurrence and parasite infestation, reduce cannibalism in cannibalistic species such as sea bass, grouper and snappers are active areas of research. Nursery production is integrated with fry production in large commercial facilities but is also done by small-scale fish farmers who have access to fry either from the wild or hatcheries. Commercial hatcheries adopt fingerling production from well-studied species in developed countries. Smallscale farmers however still rely on zooplanktons collected from the wild such as copepods, Moina, mysids, and trash fish as feed. Production is dependent on availability of feed sources and susceptibility to pathogens and parasites that come with the feed. It can also be erratic since smallscale farms are vulnerable to changes in climate and weather conditions. Further technological advancement in marine fish hatcheries will increasingly be led by commercial establishments and industries developing equipment like photobioreactor for microalgae to produce algal paste, or methods to develop intensive systems for rotifer culture. Research institutions will however need to support the needs of the small-scale farmers and hatchery operators who may not be able to apply costly products from these companies by developing innovative simple techniques that can improve culture systems such as producing fry and fingerlings in mesocosm pond system, appropriate use of probiotics as water stabilizer, and production of zooplankton in ponds.

The reality of declining quality of coastal areas has been evident for many developing countries, especially in Southeast Asia. In the Philippines, rural coastal zones and estuaries are now being characterized by declining wild fisheries resources and degrading environment. This paper presents, as an example, the typical rural coastal towns of New Washington and Batan in Aklan province, Philippines and showcases how the concept of shrimp stock enhancement can provide incentives to restore the environment and provide sustainable fishing livelihood in the area. The New Washington-Batan Estuary in northeast Panay Island, Philippines was a productive fishing ground that has been in a state of degenerating brackishwater fisheries and estuarine environment. Average daily catch composed of various species decreased from 24 kg in 1970s to 0.7 kg at present. Shrimp fisheries, the most important livelihood, declined in quality and quantity. The highly-priced and once very abundant tiger shrimp Penaeus monodon was replaced with smaller-sized and lower-priced species like the Metapenaeus ensis. These can be attributed to the conversion of 76% of mangroves to culture ponds in the past 50 years and more than 400% increase in fishing gears since the 1990s. The need to reduce fishing structures and rehabilitate mangroves is evident. However, these drastic changes directly affect fishers livelihood. This paper explores the prospects of P. monodon stock enhancement as positive reinforcement for the estuary s rehabilitation. Number of gears per fisher may have to be reduced but shrimp catches will be relatively high-priced. Simulations with additional tiger shrimp caught due to stock enhancement show that fishers can increase income by more than 4 times from their current PhP 34 gear-1 day-1. Campaigns on the importance of mangrove especially as shrimp habitat can encourage local communities to reforest the estuary especially in abandoned ponds. With effective management, law enforcement, and sustained support from different sectors, shrimp stock enhancement can be a positive strategy in estuarine rehabilitation and livelihood sustainability in the New Washington-Batan Estuary.