In this study, locally available marine species were tested, milkfish (Chanos chanos) as the fed species, seaweed (Kappaphycus alvarezii) as inorganic-extractive species for the water column, and sandfish (Holothuria scabra) as organic-extractive species on the sediments. This study aims to verify and improve IMTA systems suitable for farm conditions in coastal areas in the Philippines, with emphasis on mitigating the environmental impacts of mariculture of milkfish.

This study aimed to integrate the mangrove clam Anodontia philippiana, which has the capacity to assimilate sulfide in a pond culture system with milkfish Chanos chanos and seaweeds Gracilariopsis heteroclada. Specifically, it aimed to know the effects of integrating other commodities on the growth and survival of milkfish, the primary culture species in IMTA in ponds.

The study was conducted within the integrated finfish broodstock facility complex of SEAFDEC/AQD at Tigbauan, Iloilo, Philippines. The broodstock facility has a water recirculating system. The 500-ton capacity broodstock/spawning tanks were stocked with 25 grouper (Epinephelus coioides) and 90 milkfish (Chanos chanos) breeders. Water from the broodstock tanks passes through the sedimentation tank, then through the filter tank before it goes back to the broodstock tanks. The filter tank has an area of 20 m², a water depth of 25 cm, and a water flow rate of 43 L sec^-1 (≈3720 m³ day^-1).

Threshold infection level is the pathogen load of the test animals measured before the appearance of clinical signs and mortality. This study aims to establish the threshold infection levels of WSSV in different weight ranges of Penaeus vannamei using qPCR. Artificial infection experiments were conducted using four weight ranges (3–5 g, 7–8 g, 15–18 g, and 22–25 g). The LD₅₀ of the different weight ranges of shrimps were achieved at viral dilution of 10^-6 and 10^-5 after 216–240 hpi, and the viral loads of these inoculums have a range of 10⁵–10⁶ WSSV DNA copies/g. The viral loads of the samples in the timecourse infection experiments when the mortalities started was determined at 10⁹ WSSV DNA copies/g, while for the survivors was at 10⁶ WSSV DNA copies/g. The threshold infection level of WSSV in shrimp was determined at 10⁷ to 10⁸ WSSV DNA copies/g. It was also found out that the threshold infection level was not weight dependent.

Infectious diseases caused by viruses and bacteria are a major threat to sustainable shrimp farming globally. Since early 80’s viral diseases such as White Spot Disease, Taura Syndrome disease have caused enormous losses to shrimp aquaculture both in eastern and western hemisphere. As the shrimp industry tried to recover from the onslaught of these diseases, a bacterial, Acute Hepatopancreatic Necrosis Disease (AHPND), also known as Early Mortality Syndrome, and a fungal disease Hepatopancreatic Microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) are now posing new threat to shrimp aquaculture. Acute Hepatopancreatic Necrosis Disease is caused by Vibrio spp. expressing plasmidborne binary toxins, PirA and PirB that is similar to entomopathogenic bacterium, Photorhabdus encoded toxin. In 2009, AHPND emerged in China and since then spread to many countries in East Asia and in the Americas. Another disease that has caused alarm in recent year is Hepatopancreatic Microsporidiosis (HPM) caused by Enterocytozoon penaei (EHP), a microsporidium. While AHPND causes acute infection and large-scale mortalities, EHP causes chronic infection and results growth retardation and size variation in population reducing marketability of the infected shrimp. Both diseases affect hepatopancreas, an organ involved in metabolism and humoral immunity in shrimp. The binary toxin, PirA/ PirB are the primary virulence factor for AHPND, but specific virulence factor(s) for EHP is not known. It is, however, known that EHP does not have mitochondria and appears to transport ATP from the cytoplasm of infected cells as it contains ATP transporter genes in its genome. EHP has been shown to be a risk factor for AHPND. Due to lack of therapeutics, preventative measures remain as a corner stone for managing these diseases and efforts are underway to develop genetically improved lines of shrimp having resistance to AHPND and EHP.

Aquaculture is an important industry in Thailand which has been established more than two decades ago. The cultured species are divided into two main groups; shrimp and finfish farming. The major cultured shrimp species are Penaeus vannamei (Pacific white shrimp), P. monodon (black tiger shrimp) and Macrobrachium rosenbergii (giant freshwater prawn), whereas the finfish are Oreochromis sp., Lates calcarifer and Epinephelus sp. Also, ornamental fish such as Cyprinus carpio (Koi carp), Carassius spp. (goldfish), and Betta splendens (fighting fish or betta). Disease outbreaks are the key factor that affect Thailand’s aquaculture production and resulting in economic losses. The infectious diseases in aquaculture are mainly caused by viral and bacterial pathogens. In 2018, the reported shrimp pathogens are white spot syndrome virus (WSSV), yellow head virus (YHV) genotype 1, Taura syndrome virus (TSV), infectious hypodermal and haematopoietic necrosis virus (IHHNV), Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease (VPAHPND), and microsporidian Enterocytozoon hepatopenaei (EHP). On the other hand, the reported pathogens in finfish are Betanodavirus causing viral nervous necrosis (VNN), Tilapia lake virus (TiLV) and Streptococcus sp. etc. In Thailand, the Department of Fisheries (DOF) is the competent authority for various aspects of aquatic animals including aquatic animal health. Strategies to prevent and control diseases in aquatic animals include issuance of legislations/regulations, implementation of biosecurity measures, disease surveillance programs, capacity building, cooperation with international and national organizations. Moreover, DOF has developed contingency plan in dealing with aquatic animal disease emergencies through the provincial fisheries officer. The provincial fisheries officer acts as director of emergency aquatic animal disease control center in each province, while Aquatic Animal Health Research and Development Division (AAHRDD) and Songkhla Aquatic Animal Health Research and Development Center (SAAHRC) serve as disease diagnosis and laboratory testing centers. Because of the above actions, we are capable of preventing and controlling disease outbreaks in the country. But during the occurrence of some diseases, we have no treatment to support and completely solve the problem. Example are viral diseases, unlike bacterial diseases which can be treated by using chemical or drug. Furthermore, there are a few researches that could be applied in farm level. Especially shrimp which has no adaptive immunity, so it is difficult to develop vaccine compare to fish. Therefore, DOF mostly recommended farmers to follow the good management practices on aquatic animal health for promoting sustainable aquaculture.

The national aquatic animal disease surveillance and reporting system is implemented by the Bureau of Fisheries and Aquatic Resources in coordination with other recognized laboratories. It covers the OIE/NACA listed diseases particularly those that cause major problems in aquaculture. The fisheries laboratories continuously enhance their capabilities to support the surveillance activities, controls on transboundary movement of aquatic animals, and provide services to the fish farmers. Programs are implemented to strengthen the aquatic animal health services in the country. Promotion of Good Aquaculture Practice and implementation of biosecurity measures are being done to prevent disease occurrences. Collaboration with other institutions on aquatic animal health programs are also established. The paper provides the information on the country’s status on aquatic animal health management.