Shrimp is a high-value commodity and one of the major aquaculture species in the world, including the Philippines. The shrimp farming industry is dominated by the black tiger shrimp Penaeus monodon and the Pacific white shrimp, Penaeus vannamei. Intensification in shrimp aquaculture to meet the global demand resulted to several socio-economic and biophysical production bottlenecks. Consequently, the issues besetting the industry had raised several questions on its sustainability. In particular, viral diseases remain a constant threat and a significant concern in many shrimp producing countries especially in the developing world. In this chapter, current knowledge on major viral pathogens affecting shrimp aquaculture in the Philippines is presented and discussed. The discussion is focused on white spot syndrome virus (WSSV), monodon baculovirus (MBV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), hepatopancreatic parvovirus (HPV). yellow head virus (YHV), and taura syndrome virus (TSV). Updates on their clinical signs, transmission and distribution are presented. Records of incidence in the Philippines are provided as well. The second half of the chapter discusses some of the methods how to control viral diseases in shrimp farming with a particular focus on vaccination, biosecurity and diagnostics.

Colour vision depends on sufficient ambient light and becomes ineffective at a particular low light intensity. It is not known how decapod crustaceans see colour in dim light. In the present study we investigated the colour vision threshold in larvae of the giant freshwater prawn Macrobrachium rosenbergii in a tank under natural illumination. Plastic beads of different colours (blue, red, yellow and white) in various combinations were suspended in the tank. The larvae swam straight toward the beads and gathered around them. The number of larvae was highest on the blue and white beads. The luminance in the tank was then gradually decreased by covering it with different numbers of layers of black cloth, and the response of the larvae to the beads was video-recorded under infrared illumination. The preference for blue and white beads remained manifest as the luminance was reduced from 418 to 0.07 cd/m², but not at 0.02 cd/m², indicating a colour vision threshold between 0.07 and 0.02 cd/m². The larvae have apposition compound eyes with large optical parameters, comparable to those of apposition eyes of nocturnal insects, which presumably capture more light and show enhanced sensitivity, enabling the larvae to see colour in dim light.

Milkfish hatchery broodstock are either from on-grown wild-caught or hatchery-produced fry/juveniles. To determine if a marker-assisted management scheme can be formulated for improved milkfish hatchery production, milkfish stocks were genetically characterized using nine novel short tandem repeats or microsatellites. Eight wild-bred Philippine stocks (CLA, CUR, CAM, SIH, SBH-I1, HH, PAL and ZH-P₀), four hatchery-bred stocks (SBH-I2, SBH-D, BoH and ZH-F₁), two farm stocks of known mixed lineages (SPH and BDH) and one Indonesian hatchery-bred stock (WJH) were assessed. WJH was included since milkfish fingerlings from Indonesia reared in Philippine farms could be developed into future broodstock. Mean allelic richness (Ar) was highest in wild-bred stocks (9.5) and lowest in hatchery-bred spawners (9.1). Mean expected heterozygosities (He) were relatively similar in all stocks with wild-bred stocks slightly higher (0.67) than the others. An analysis of molecular variance indicated significant yet low genetic differentiation among stocks (F_ST = 0.013; p = .000) where variation (98.6%) was explained by intra-stock differences. In some of the domesticated stocks, reductions in mean allelic richness were observed in first generation hatchery broodstock (e.g. ZH-F₁; Ar = 8.3), compared with their founder stock (e.g. ZH-P₀; Ar = 9.4). The Indonesian stock was similar to local wild-bred stocks based on genetic variability indices; thus, it might be likely that the local stocks’ fitness traits could be comparable with the imported milkfish stock which has been perceived to be better. The quality of locally available farmed milkfish and prospects of formulating a broodstock management scheme for the production of good quality milkfish seedstock are herewith discussed.

Information on the sensory basis of shrimp feeding provides the means for assessment of the effectiveness of food items in terms of smell, taste, size, and colour. This chapter summarizes information about the sensory basis of the feeding behaviour of the giant freshwater prawn (Macrobrachium rosenbergii) and the marine whiteleg shrimp (Litopenaeus vannamei). Existing literature on these shrimp species and other decapod crustaceans is reviewed, and unpublished experiments using the selective sensory ablation technique to determine the involvement of vision, chemoreception, and touch sense in the feeding behavior of the juveniles of M. rosenbergii and L. vannamei are also described. To determine the role of vision in feeding, the eyes of the juveniles were painted over (deprived of vision) with white manicure and their feeding response to commercial pellets was compared with those with untreated eyes. The untreated eyed juveniles detected and approached a feed pellet right away, but the specimens blinded by the coating detected a pellet only after random accidental touch with the walking legs while roaming on the aquarium bottom. Juveniles that had learned to feed on pellets showed food search and manipulation responses to a pellet-like pebble without smell and taste. The early larvae (zoeae) of M. rosenbergii already have colour vision (that likely persists through life) and colour preference for blue and white. The adults of L. vannamei discriminated a blue-colored well among seven grey wells in a palette, also showing colour vision in this shrimp. A behavioural experiment with dyed prawn flesh showed that L. vannamei has innate color preference for yellow food over black, red, green, and blue food regardless of the background colours of the aquarium bottom. To disrupt chemoreception, the juveniles of both the species were abruptly transferred to water of drastically different salinity and the osmotic ablation destroyed the chemosensitive sensilla. The osmotically ablated juveniles approached a pellet right away but failed to ingest it; they had learned the visual cue and texture of the pellets and recognized them by vision and tactile sense. To determine the role of sensory appendages in feeding of L. vannamei juveniles, the antennal flagella, antennular flagella, and the pincers of the pereiopods were ablated. The ablated juveniles roamed the bottom, touched a pellet at random, grabbed it with the maxillipeds, and ingested it. Subsequently they learned to lower the head, actively swim forward, sweep the bottom with the maxillipeds, detect a pellet, and ingest it—thus indicating a plasticity in feeding behaviour in L. vannamei.

Feeding trials were conducted to determine the optimum partial replacement level of soybean meal (SBM) with fermented copra meal (FCM). Isonitrogenous and isocaloric diets containing 0, 5, 10, 15, 20, and 25% of the locally produced FCM partially replacing SBM protein by 0, 12, 27, 41, 56, and 71%, respectively and fully replacing copra meal were formulated. The diets were fed to the fish with an initial weight of 2.83±0.14 g for 12 weeks. Thereafter, the best diet was further tested in a preliminary feeding trial in brackishwater grow-out ponds to verify the performance of the formulated diet against a commercial milkfish feed in an outdoor grow-out system. The results of the indoor tank feeding trial indicated that weight gain of the fish was significantly better in the group fed diet 2, with 5% dietary FCM but further increase in the FCM inclusion level up to 20% of the diet did not exhibit statistical differences against the control. Moreover in the preliminary pond feeding trial, growth and feed conversion ratio (FCR) of the fish fed the FCM diet were significantly higher than the commercial control diet. Survival and nutrient composition of the fish carcass were not adversely affected by the treatments. Hence, optimum dietary FCM inclusion level was determined at 5% of the milkfish diet replacing 100% copra meal and 12% SBM protein. However, in terms of economics, up to 20% FCM can be included in the diet replacing 56% SBM protein may be possible with growth comparable to the FCM-less control.

Luminous vibriosis is a devastating infection of penaeid shrimp larvae and juveniles causing heavy mortalities. To counter the bacterial pathogen, Vibrio harveyi, shrimp farmers in the Philippines modified their growout culture method of the black tiger shrimp, Penaeus monodon, juveniles and developed the greenwater culture technique. This culture method involves the use of pond water of all-male, saline-tolerant Oreochromis hornorum as rearing water for the culture of shrimp juveniles in ponds. Such a modified culture of P. monodon juveniles was found effective in preventing the onset of luminous vibriosis. Basic studies revealed that antiluminous Vibrio factors are inherent in the bacterial, fungal, and microalgal flora of the tilapia water, dermal mucus, and gut that singly or collectively inhibit the growth of V. harveyi, in vitro. The skin mucus studies of other brackishwater fish species showed that the siganids, Siganus guttatus, and red hybrid tilapia (Oreochromis niloticus × Oreochromis mossambicus), as well as sea bass, Lates calcarifer, are promising alternative fish species for this novel shrimp culture method. A review of pond-simulated studies in tanks and ponds, similarly, confirmed these findings and the impact of the greenwater culture technique on water quality, including its economic benefits to the farmer. The greenwater culture of shrimp can sustain the successful production of shrimp juveniles by inhibition of the luminous Vibrio. This culture method is also currently used in the growout culture of the white shrimp, Litopenaeus vannamei.

In the Philippines, salt tolerant Nile tilapia strains have been developed and promoted for culture to increase tilapia production in brackishwater pond systems previously dedicated for milkfish and/or penaeid shrimp culture. This was mainly done to address the decline in the production of such major commodities in ponds and/or cages brought about by diseases and mass fish kills caused by intensified culture methods. The present paper focuses on the different salt tolerant Nile tilapia stocks that have been developed and disseminated in the Philippines, the culture practices involved, as well as the prospects for profitable production of Nile tilapia in saline conditions.

The paper examines digitization and preservation initiatives in selected academic and research libraries in the Philippines. It identifies the drivers for the projects, practices followed, and issues encountered. Most of the projects were initiated by the librarians in cooperation with information and communication technology personnel. The selection of the materials for digitization was based on demand, the condition of the print format, and importance of the materials for future use. Conversion into microfilm from digital format, use of Internet mirror sites, and off-site repositories of data on hard disks were some of the preservation methods practiced by libraries. Challenges faced by digital curation activities include the need to develop digital curation skills of information professionals and researchers, and to develop the information infrastructure of the institutions and the country.

This study evaluated the effects of fertilizer type and fish density on early growth and survival of silver therapon Leiopotherapon plumbeus (Kner, 1864) larvae reared in outdoor tanks. In the first experiment, larvae (1.92 ± 0.09 mm total length) were stocked into nine, 4 m³ tanks at an initial density of 0.5 larvae L^-1 and reared for 42 days at an ambient temperature of 28.8–30.7°C. Three treatments with three replicates each were compared: organic (chicken manure, OF) or inorganic fertilizers (ammonium phosphate, IF) applied once every 2 weeks, and the unfertilized (NF) tanks serving as the control group. Water quality, zooplankton densities, survival or growth of L. plumbeus larvae did not vary significantly in either fertilized or unfertilized tanks. Fertilization resulted in elevated nutrient concentrations, which did affect survival (2.10%–6.07%) of the fish larvae. In the second experiment, larvae were stocked at densities of 0.4 or 0.6 larvae L^-1 in tanks fertilized at 4–5 days interval with OF and IF for 30 days. Growth performance of L. plumbeus larvae was affected by fish density, with significantly larger (20.04 ± 2.65 mm in total length) and higher specific growth rate (SGR; 6.97 ± 0.48% day^-1) at 0.4 larvae L^-1 than at 0.6 L^-1. Fry production did not vary significantly between fish density treatment groups given the same fertilizer types, but survival rates were improved at 0.4 L^-1. Together, production of L. plumbeus larvae in outdoor tanks can be optimized at a lower stocking density, regardless of the type of fertilizer used.

The beneficial effects of PHB as supplement for giant tiger prawn Penaeus monodon postlarvae using a short-term enrichment strategy via Artemia were examined. The effects of co-supplementing with a lipid emulsion were also evaluated to determine whether it yielded an additional benefit. Results on the average weight and larval development were not significantly different among postlarvae fed the different dietary treatments, indicating that PHB supplementation could not be used to stimulate growth in P. monodon postlarvae while such positive results have been reported in other aquaculture species. Nonetheless, significantly higher survival was obtained in postlarvae fed PHB-enriched Artemia irrespective of lipid enrichment. In addition, PHB increased the survival of the postlarvae after exposure to a lethal dose of ammonia. Lipid supplementation nullified this effect. The cumulative mortality of postlarvae subjected to a sublethal concentration of ammonia for 24 h and subsequent exposure to pathogenic Vibrio campbelli showed that PHB but not lipids could effectively enhance the resistance of the postlarvae. Co-supplementing lipids even significantly decreased this outcome. Our study indicates that PHB supplementation increases the quality of larval P. monodon and their chance of surviving under adverse environmental conditions. The short-term co-supplementation with lipid emulsion did not add to these effects.