The abdominal segment deformity disease (ASDD) is a new shrimp disease reported only in cultured Penaeus vannamei in Thailand. Shrimp with ASDD have deformed abdominal segment, jagged gut line and bumpy surfaces. Similar signs were observed in cultured P. indicus in the Philippines. However, aside from the signs described for ASDD, some P. indicus showing abdominal segment deformity syndrome (ASDS) had more severe deformities up to the extent that the number of body segments was reduced due to fusion. Shrimp with fused body segment deformity (FBSD) had four instead of five pairs of legs. To account the prevalence of the deformities in P. indicus, shrimp were classified into grossly normal shrimp (NS), shrimp with abdominal segment deformity syndrome (ASDS) and shrimp with fused segments (FBSD). Out of the shrimp sampled, 83.4 ± 5.4% was NS, 10.9 ± 6.2% was ASDS and 5.7 ± 3.0% was FBSD. Morphometric characteristics of the shrimp were measured. There was no significant difference in body weight (BW) among male and female NS, ASDS and FBSD. In both sexes, total length (TL) of FBSD was significantly shorter compared to NS and ASDS. Shrimp samples were also screened to be negative for known infectious viral diseases including white spot syndrome virus (WSSV), infectious hypodermal and haematopoietic necrosis virus (IHHNV), infectious myonecrosis virus (IMNV), P. vannamei nodavirus (PvNV), Macrobrachium rosenbergii nodavirus (MrNV) and Taura syndrome virus (TSV). Occurrence of ASDS and FBSD in post-larvae (PL) produced from captive and wild spawners were also determined. Based on a tank experiment, no significant difference was detected between the percentages of ASDS in PL produced from wild or captive spawners but FBSD was only noted in PL produced from the latter. Deformities generally did not affect the size of P. indicus except for the reduced length of shrimp with FBSD which when coupled with missing pleopods could lead to major economic loss for shrimp farmers if not addressed properly.

Nutritional qualities of fish processing by-products can further be improved through enzymatic hydrolysis. The objective of this study was to elucidate the efficacy of hydrolysed milkfish offal at different inclusion levels when fed to juvenile grouper, Epinephelus fuscoguttatus, with an initial body weight of 2.88 ± 0.06 g. The animals were fed for 56 days with seven diets supplemented with 0 (control), 5%, 15% and 25% of milkfish offal (MO) and milkfish offal hydrolysate (MOH). The diets were formulated to be isonitrogenous (45%) and isolipidic (11%). The diets were assigned to 21 tanks (15 fish per tank) with each diet having three replicates. Results from the experimental trials indicated that feed conversion efficiency, feed intake and weight gain of fish significantly (P < 0.05) improved when fed diets with MOH. No significant differences within the rest of the dietary treatments were observed. Survival rate (>90%) did not differ in all the dietary treatments. Proximate composition (crude protein, crude fat and ash) indicated no significant difference among fish fed from all the dietary treatments. Apparent digestibility of MOH indicated a 95% and 66% digestibility for protein and dry matter respectively. Plasma stress parameters (cortisol and glucose) were not influenced by the dietary treatment when fish were subjected to an acute stressor (5-min chasing). Liver morphology indicated normal hepatocyte shape and the presence of lipid droplets in fish fed from all the dietary treatments. The results indicated that milkfish offal processed as hydrolysate can be utilized in grouper diets and can promote growth and feed efficiency when supplied at 10–15%.

The embryonic and larval development of hatchery-reared silver therapon Leiopotherapon plumbeus are described to provide essential information on the early life history of this species. Egg size, larval size at hatching, yolk resorption rate, onset of feeding and development of some morphological characters were examined. Fertilized eggs (430–610 µm in diameter) were spherical, yellowish, demersal and slightly adhesive. First cleavage occurred 6 min post-fertilization and embryos hatched 21–24 h post-fertilization under ambient temperature of 27.5 ± 0.1 °C. Newly hatched larvae [1.79 ± 0.04 mm in total length (TL)] with yolk volume of 0.579 ± 0.126 mm3 had no functional or pigmented eyes, mouth or digestive tract. The eyes became fully pigmented and mouth opened [31 and 36.5 hours post-hatching (hph)] shortly before yolk resorption at 39 hph and when larvae had grown to 2.65 ± 0.14 mm in TL. Some morphological characters such as total length, pre-anal length and eye diameter decreased following yolk resorption, which also coincided with the development of foraging capacities shortly before exogenous feeding was initiated. L. plumbeus larvae initiated exogenous feeding at 54 hph, indicating a short (15 h after yolk resorption) transitional feeding period. Larval growth at the early stages of development (54–72 hph) was rapid and steadily increased from 288 to 720 hph, when larvae, 12.05 ± 4.02 mm in TL, closely resembled the external characteristics of their adult conspecifics.

Acute hepatopancreatic necrosis disease (AHPND) is caused by unique strains of Vibrio parahaemolyticus (VP_AHPND) and V. harveyi that have transferrable plasmid carrying the virulent PirAB-like toxin genes. The genomes of VP_AHPND strains and V. harveyi from Thailand and Viet Nam, respectively, have been characterized by our group. The genome of VP_AHPND strains from Mexico, Viet Nam, and China have also been studied by other groups. We have developed a conventional polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) methods for the detection of AHPND using a primer set that targets the PirAB-like toxin genes of VP_AHPND. We have characterized the toxin genes of VP_AHPND strains and also constructed a recombinant plasmid (broad host range) carrying PirAB-like toxin genes. Non-VP_AHPND strain N7 which does not carry the plasmid and strain FP11 which is carrying a plasmid not coding for the toxin genes were transformed with the plasmid carrying PirAB-like toxin genes. As a result, the transformed N7 and FP11 strains became virulent and killed whiteleg shrimp (Penaeus vannamei) similar to or at par with the virulence of VP_AHPND strain. We then fed the whiteleg shrimp with commercial feed containing the formalin-killed VP_AHPND strain. After 2 days of feeding, all of the whiteleg shrimp died. These results clearly indicate that the PirAB-like toxin is the virulence factor of VP_AHPND.

We have been investigating the virulence mechanism of the PirAB-like toxin produced by VP_AHPND strains. First, we calculated the copy number of plasmid encoding the PirAB-like toxin genes of several VP_AHPND strains. The copy number of the plasmid varied, ranging from 1 to 36 copies. Interestingly, VP_AHPND strains carrying low copy number of plasmid were more virulent than VP_AHPND strains carrying high copy number of the plasmid. These results imply that the copy number of toxin genes is not an important factor responsible for the degree of virulence of the VP_AHPND strains. We are also studying other factors associated with the virulence of PirAB-like toxin. Likewise, we are developing prevention methods against AHPND including the use of formalin-killed cell vaccine, IgY additive in feed, and nano-bubble treatment of rearing water. This paper summarizes the current R&D on the disease.

Transboundary diseases have been a constant challenge for the aquaculture industry in Indonesia. In spite of this, Indonesian aquaculture has experienced a steady growth since 2010. Early mortality syndrome (EMS) or acute hepatopancreatic necrosis disease (AHPND) is a serious emerging transboundary disease of cultured shrimp that has not been reported in Indonesia. On the contrary, hepatopancreatic microsporidiosis (HPM) was first detected in 2015. Other previously reported transboundary diseases of shrimp and fish include white spot disease (WSD), Taura syndrome and infectious myonecrosis (IMN), and viral nervous necrosis (VNN) and koi herpesvirus (KHV), respectively. These diseases have been included in the surveillance program conducted in 2016. To avert the spread of these transboundary pathogens in the Indonesian aquaculture facilities and natural waters, competent authorities have been tasked to implement stringent control measures including government policy and regulation, active and passive surveillance, and strengthening farmers and stake holders awareness of the importance of disease control and health maintenance.

Acute hepatopancreatic necrosis disease (AHPND), formerly called early mortality syndrome (EMS), was first reported in 2010 among penaeid shrimps cultivated in the Mekong Delta Region of Viet Nam albeit without any laboratory confirmation. The disease subsequently spread to a wide range of shrimp production areas in the same region (Soc Trang: 1,719 ha; Bac Lieu: 346 ha; and Ca Mau: 3,493 ha), so that the Government of Viet Nam requested for technical assistance from the Food and Agriculture Organization (FAO) of the United Nations in 2011. In 2012, FAO supported Viet Nam through the project TCP/VIE/3304 Emergency assistance to control the spread of an unknown disease affecting shrimps in Viet Nam, under which the Department of Animal Health of Viet Nam (DAH) collaborated with the University of Arizona and FAO experts to carry out indepth studies to identify the etiologic agent of the disease. As a result, unique isolates of Vibrio parahaemolyticus was identified as the causative agent of AHPND in 2013. Viet Nam has been vigilant and transparent with regard to aquatic animal diseases through official notifications to the World Organization for Animal Health (OIE) and the Network of Aquaculture Centres in Asia-Pacific (NACA). AHPND outbreaks have no clear temporal pattern with black tiger (Penaeus monodon) and whiteleg (P. vannamei) shrimps showing similar incidence risk. The disease occurs at any stage of shrimp cultivation, i.e. on average about 35 days after stocking. To date, unwarranted outbreaks of AHPND in major shrimp-producing provinces in Viet Nam have been apparently regulated. Aside from AHPND, white spot disease (WSD) has also been a persistent problem responsible for serious economic losses in many shrimp-producing areas in Viet Nam. To prevent and control the further spread of infectious diseases of shrimps including AHPND and WSD, multiple control measures have been implemented including guidance of farmers to improve production conditions, facilities and biosecurity application, active surveillance of shrimp production areas for early warning, screening of broodstock and postlarvae for any OIE listed diseases, regulation on movement of stocks, and collaboration with regional and international organizations in carrying out in-depth epidemiological studies that will be needed in the formulation of pragmatic and holistic disease interventions.

A report about a disease problem in cultured whiteleg shrimp (Penaeus vannamei) was first received by the National Fish Health Research Center (NaFisH) in 2011 from Perak State showing signs of white feces and slow death leading to serious mortality rate. Later, in September of the same year, the Malaysian Shrimp Farmers Association (MSFA) reported to Department of Fisheries (DOF) severe mortalities in almost all of the whiteleg shrimp farms throughout Peninsular Malaysia. Sampling of shrimps for disease diagnosis was then conducted by NaFisH. The bacteriological and histopathological examinations revealed respectively the isolation of V. parahemolyticus and massive sloughing of hepatopancreatic epithelial cells. The disease was subsequently identified as acute hepatopancreatic necrosis disease (AHPND). From our 3-year study, the annual prevalence rates of AHPND were 50%, 26% and 73% in 2011, 2012 and 2013, respectively. At present, AHPND still persists in Malaysia but at a lower prevalence. The risk factors associated with the disease were studied, however, varied environmental and management data analyzed were inconclusive to relate any one parameter directly to the disease. To help ensure the early detection of AHPND, an experimental observation study on `gut scorecard was carried out and this was confirmed by PCR and histopathology. Validation of this technique has yet to be carried out to ensure its reliability. We also examined the potential use of some commercial products such as probiotics and disinfectants available in the market but unfortunately results showed that they were not effective in controlling AHPND. Control measures applied by the farmers such as the use of probiotics were also verified but data generated likewise appeared to be inconclusive. On the contrary, our preliminary study on the antibacterial property of the plant extracts, i.e. betel and lemongrass, incorporated in the feed showed some prophylactic and chemotherapeutic potential against AHPND. However, comprehensive in vitro and in vivo trials are still currently being undertaken to elucidate its efficacy and practical applications. To ensure the shrimp industry s sustainability in Malaysia, results of our ongoing and future studies aimed at preventing and controlling unwarranted outbreaks of AHPND and other emerging transboundary diseases of penaeid shrimps will be continually disseminated to shrimp farmers and pertinent stakeholders.

The Organization for Economic Cooperation and Development (OECD) and the Food and Agriculture Organization (FAO) of the United Nations Agricultural Outlook 2015-2024 reported that fisheries production worldwide is projected to expand by 19% between the 2012-14 base period and 2024, to reach 191 million metric tons (MT) and the main driver of this increase will be aquaculture, which is expected to reach 96 million MT by 2024, 38% higher than the base period (average 2012-14) level. Among the 7 key uncertainties that affect gains in productivity, the potential of animal disease outbreaks to affect aquaculture production and subsequently domestic and international markets are once again highlighted, although for the first time in this outlook. Another milestone document, the Blue frontiers: managing the environmental costs of aquaculture identified a number of fish health issues, including increased risk of the spread of pathogens and diseases with intensification, through increased movement of aquatic animals, inter-regional trade and introduction of new species and new strains, and through the use of trash fish or live feed; concerns on residues and development of drug resistant pathogens brought about by the abuse on the use antimicrobials and other veterinary drugs; limited availability of vaccines; environmental stressors that compromise the immune system; difficulties faced by developing countries in implementing international standards; and the need for legislation, enforcement and capacity building. The issues identified then and now are almost the same.

Addressing animal health issues in aquaculture is very challenging because the sector is highly complex (with a wide range of diversity in terms of species, systems, practices and environment, each presenting different risks), its fluid environment, and the transboundary nature where fish is considered as one of the most traded commodity, aquatic animals require more attention in order to monitor their health: they are not visible except in tank holding conditions; they live in a complex and dynamic environment and feed consumption and mortalities are hidden under water.

This paper looks at the status of a newly emerging disease of cultured shrimp, acute hepatopancreatic necrosis disease (AHPND), which has been recognized as the most important non-viral disease threat to cultured shrimp. In particular, this paper presents the highlights of the International Technical Seminar/Workshop: EMS/AHPND: Government, Scientist and Farmer Responses held from 22-24 June 2015 in Panama City, Panama, which was organized under the auspices of an FAO inter-regional project TCP/INT/3502: Reducing and Managing the Risks of AHPND of Cultured Shrimp, being participated by 11 countries, namely: Colombia, Ecuador, Guatemala, Honduras, Mexico, Panama and Peru from Latin America and the Caribbean (LAC) region and India, Iran, the Philippines and Sri Lanka from the Asian region. The Panama EMS/AHPND June 2015 event aimed to provide a platform to improve the understanding of the disease through the lens of governments, scientists and producers and collectively generate practical management and control measures. More than 100 stakeholders from 21 countries representing the government, academe and producer sectors participated in the event. The highlights contain the latest available information at that time (June 2015) about AHPND including the current state of knowledge about the causative agent, the host and geographical distribution, detection methods, risk factors, management and actions of regional and international organizations.

SEAFDEC/AQD’s Stock Enhancement Program started in 2001 with the first stock enhancement initiative on mud crab Scylla spp. funded by the European Commission. This was followed by another stock enhancement program in 2005 supported by the Government of Japan Trust Fund with seahorses Hippocampus spp., giant clam Tridacna gigas, abalone Haliotis asinina, and sea cucumbers Holothuria spp. as priority species. This paper discusses the release strategies that have been established for giant clam, abalone and mud crab.

The total global production from capture fisheries has plateaued since the mid 90s. This stagnation in production or reduced productivity of the world’s coastal and marine wild fisheries is caused by overfishing and degradation of habitats through coastal development and destructive fishing methods. Reports have shown that if the current fishing trends continue, all of the commercial fisheries will have collapsed by 2050. To boost production, scientists, fisheries managers, government agencies, and NGOs have been looking at ways of enhancing fish stocks. Replenishing depleted stocks may be done by regulating fishing effort, restoring degraded nursery and spawning habitats or through resource enhancement. Resource enhancement using individuals reared in aquaculture facilities or seed stocks abundant in the wild is becoming a popular method of supplementing depleted stocks. It is one of the many strategies that could help address the decreasing fisheries production in the wild. A brief history of resource enhancement, the aquatic species released in the different countries in the region, the reasons for releasing stocks, and the issues involved, are discussed briefly in this paper. Among the main reasons for resource enhancement are to increase production or enhance stocks and increase food supply and/or family income. Other reasons include protection of endemic and maintenance of endangered species, rehabilitation of degraded natural habitats and for recreation fisheries, among others. Age or size of seeds, seed quality, genetics, governance, economics, biodiversity conservation, politics, and the introduction of exotics are among the resource enhancement issues identified in the region.