The intestinal microbial community has crucial functions for their vertebrate host. Several studies in fish showed that their gastro-intestinal tract harbors a diverse population of bacteria that supplies exogenous nutrients, enzymes, fatty acids and vitamins to their host. Most studies on probiotics involved their practical use for aquaculture, but are limited for the ornamental fish industry. Hence, this study aimed to screen the gut microbiota of a freshwater fish, Anabas testudineus, for potential probiotic candidates for the ornamental fish industry. Gut bacteria were obtained from the gut of climbing perch by plating of serially-diluted samples of the gut contents onto Nutrient Agar (NA). In vitro antagonistic activities of these gut bacteria against a fish bacterial pathogen, Aeromonas hydrophila, were determined by spot-on-lawn method. Isolates that had strong antagonistic activities against A. hydrophila were further characterized using standard staining and biochemical techniques. Rapid screening of the gut microbiota of climbing perch resulted in the identification of a promising probiont, Kurthia gibsonii through sequencing of its 16S rRNA gene. This bacterium is a member of the Planococcaceae family and is a Gram-positive, non-spore forming and rod-like bacterium. The isolate is yellowish in appearance and has a filamentous colony on nutrient agar. It exhibited catalase and amylase activities. Immersion challenge of freshwater ornamental fish with the bacterial isolate showed no mortality at 15 days after exposure. Taken together, the present study demonstrated that the gut microbiota of fish is a rich source of probiotic candidates that can be utilized during the culture of freshwater ornamental fish.

The world is currently experiencing an age of information overload, as information about anything and almost everything is easily obtainable. However, essential information that could help a community strive and survive is often left unread in scientific papers and grey literature, thus unable to reach its intended audience. Fishers, specifically in developing countries such as the Philippines, are still known to be information-poor despite the rich scientific knowledge produced by concerned agencies. This chapter describes and analyses the information needs and seeking behaviour among fishers in the coastal communities in Iloilo, Philippines. Taking the initiative and time to profile how specific groups consume information can help narrow the information gap and aid concerned agencies to create and conceptualise successful, sustainable, and effective information, education, and communication campaigns.

Nursery production of shrimp is usually done in small ponds; however, the use of small and circular tanks with plastic liners is gaining popularity. From an industry standpoint, there is still a need to assess how nursery systems can be of benefit to the shrimp production cycle. Hence, the use of small circular tanks coupled with the incorporation of biofloc technology was assessed in terms of its viability during the nursery production of the Pacific whiteleg shrimp, Penaeus vannamei. A 450m² plastic lined circular tank was installed and prepared for the stocking of P. vannamei postlarvae (PLs) at a density of 500 PLs per m². Biofloc was produced and maintained throughout the nursery phase using brown sugar as carbon source at a carbon to nitrogen (C:N) ratio of 10. Water quality was monitored daily, while presumptive Vibrios were enumerated weekly. Sampling for growth was done at the 14^th day post-stocking and weekly until harvest on the 30th day. The different water quality parameters were within optimum levels required for shrimp growth. Presumptive Vibrios were dominated by the yellow colonies. At the end of the nursery phase, there was 100% survival and the shrimp attained an average body weight of 1.26 g and a feed conversion ratio (FCR) of 0.43. Our results indicate that the use of small circular tanks with biofloc during the nursery production phase of whiteleg shrimp is feasible and can be incorporated in the grow-out culture of this shrimp species.

The present study was carried out to assess the toxic effect and determine the lethal concentration of dried garlic (Allium sativum) powder on the orange-spotted grouper (Epinephelus coioides) juveniles. Laboratory static bioassays were conducted to determine the 96-h LC₅₀ of different concentrations of garlic (0, 30, 60, 90, 120, 150 and 180 mg L^-1) on grouper juveniles (mean weight, 35.4±6.18 g and mean length, 13.2±0.51 cm). The 96-h LC₅₀ was 74.78 mg L^-1 with lower and upper confidence limits of 62.8 and 89.06 mg L^-1, respectively. All fish exposed to 30 to 180 mg L^-1 exhibited rapid movement, faster opercular activity and erratic swimming whereas at higher concentrations (90 mg L^-1 to 180 mg L^-1) fish showed additional behavioral changes such as loss of balance, lethargy, gulping for air and respiratory distress. Water quality parameters were within the recommended acceptable limits. This LC₅₀ value can be used as a baseline reference to generate an effective concentration of garlic for future prophylaxis and treatment for parasitic, viral and bacterial infection in grouper.

From 2008 to 2014, we monitored the abundance and daytime habitat use of the freshwater shrimp Macrobrachium yui at a fixed site on a tributary of the Xuang River in northern Laos. Throughout the monitoring period, the shrimp M. yui showed strong preference for cobble and small boulder substrates, as well as moderate preferences for 21–30 cm depth and the midstream (251–350 cm distance from the bank) as daytime habitat factors. The shrimp M. yui, on the other hand, exhibited intense avoidance for shallower water depths (less than 10 cm), stagnant (0 cm s⁻¹) and faster water velocity (greater than 60 cm s⁻¹), finer substrates (from silt to gravel), and stream margin (less than 50 cm from the bank). During the day, the habitat with the cobble and small boulder in the midstream is probably the best place for the shrimp M. yui to hide from predators. The abundance of the shrimp M. yui had positive and negative correlations with water depth and sand percentage in the bottom sediment, respectively. It suggests that a decrease in water depth caused by increased deposition of fine sediment from the catchment has a negative impact on the shrimp abundance.

The International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC) through the Aquatic Commons Board approved the deployment of IAMSLIC Digital Fisheries Library in the Philippines during the 2015 Conference. The digital library utilized the LibraryBox, a portable, open source distribution tool. This standalone wireless access is ideal for fisheries schools in the area due to limited or no Internet access and intermittent electrical power conditions. With the aim of providing access to SEAFDEC Aquaculture Department (AQD) publications in these schools, more than a thousand publications that were already made available in SEAFDEC/AQD institutional repository were also added in the box. The box contained over 26,000 publications, reports, articles and documents on all aspects of fisheries that are freely available. SEAFDEC/AQD is the first institution in the country to launch t he project in July 2016 using LibraryBox. Five boxes were distributed in Philippine fisheries libraries devastated by Typhoon Yolanda or hazed by fire. This study examined the factors that influence student’s acceptance and attitude towards the IAMSLIC Digital Fisheries Library. A survey was distributed to selected fisheries and marine biology undergraduate students in the Philippines. Relevance, perceived usefulness, perceived ease of use, screen design and behavioral intention to use the digital library were determined.

Viral nervous necrosis (VNN), also referred to as viral encephalopathy and retinopathy (VER), has been reported in at least 120 cultured or wild marine and freshwater fish species and has caused serious economic losses among farmed marine fish species in the past decades. Since the first description of this disease at the end of the 1980s, substantial amounts of researches have been instrumental in understanding the mechanisms involved in fish infection, development of reliable diagnostic methods, and disease prevention and control. This chapter presents some important aspects of the disease with particular emphasis on etiologic agent, clinical signs and gross pathology of the disease, histopathology, disease risk factors, virus propagation and identification, molecular diagnostics, and concomitant prevention and control methods.

The nearshore (Soya Warm Water (SWW)) and offshore (Intermediate Cold Water (ICW) and Okhostk Sea Low Salinity Water (OSLSW)) waters in the Okhotsk Sea differ substantially in their physico-chemical characteristics. Thus, the extent to which water mass mixing impacts phytoplankton dynamics in the Japanese scallop Patinopecten yessoensis culture areas needs to be assessed to properly manage scallop stocks. This study examined the phytoplankton dynamics in nearshore (SWW) and offshore (ICW and OSLSW) waters and phytoplankton response to water mass mixing (SWW + ICW, OSLSW + ICW) for 5 days in spring (2007) and summer (2007–2009) microcosm experiments. Increased chlorophyll a concentration in ICW was observed due to higher nutrients available for phytoplankton uptake than in OSLSW and SWW at the start of each microcosm experiment. In comparison to spring microcosm, mixing of SWW + ICW promoted higher chlorophyll a concentration and faster Si(OH)₄ utilization than in OSLSW + ICW in summer. In addition, the size structure of chlorophyll a differed from micro-size (>) in SWW + ICW to nano-size (<) chlorophyll a in OSLSW + ICW. Suspended particulate organic matter (SPOM) \(\mathsf{\delta^{13}C}\) ratios were positively correlated with chlorophyll a in both mixed microcosms whereas SPOM \(\mathsf{\delta^{15}N}\) isotopic ratios were inversely related to nitrate concentration in SWW + ICW, except in spring. This suggests that stable isotopes can be used in predicting phytoplankton biomass and nutrient utilization. In comparison to microcosm experiments, nearshore water column structure suggests vertical water mixing in summer to autumn when phytoplankton biomass and micro-size fraction were at maximum. Taken together, the advance of nutrient-rich ICW to nutrient-poor nearshore areas in the Okhotsk Sea resulted in increased chlorophyll a biomass and dominance of micro-size phytoplankton in summer, potentially enhancing nutrient and food supply to bottom-cultured scallops as suggested by both microcosm experiments and field observations.

Polychaete is considered the best maturation diet for penaeids; however, fluctuating supply and quality warrant detailed studies to understand the specific maturation-promoting factors present in polychaete. Indian white prawn, Penaeus indicus, was fed diets supplemented with different fractions of Marphysa sp. extracts. Fractions, such as the total soluble fraction (TSF), neutral lipid fraction (NLF), and polar lipid fraction (PLF), were incorporated in the maturation diet at 0.25, 0.50, and 1.00% following a 3 × 3 factorial design. One group was fed with basal diet (BD), and another was fed with fresh squid, mussel, and polychaete, serving as the control. After a 30-day feeding trial, results showed that the inclusion of polychaete extracts in the diet significantly improved P. indicus maturation compared to groups fed BD and control with 40% maturation rates (MR) (p = 3.4 × 10⁻⁴). MR was optimum in groups receiving diets supplemented with ≥0.5% TSF (70.00% ± 0.00) and NLF (60.00% ± 5.77). Similar improved MR was achieved in treatments receiving ≥0.25% PLF supplementation (60% ± 0.00). Accordingly, relative expression of ovarian vitellogenin mRNA of broodstock fed under 0.25 and 0.50% PLF group was 4.44 and 3.96 folds higher than BD, respectively (p = 0.003). No significant differences were detected in the broodstock survival, latency period, hepatosomatic, and gonadosomatic indices. Biochemical content analyses showed no significant differences among the nine treatments except for broodstock's higher ovary protein content in the TSF group (p = 0.037). This study highlights PLF as the most potent component of the polychaete extract in promoting gonad maturation in P. indicus maturation supplemented at a 0.25% optimum inclusion level.