As part of the technology verification exercise for technologies developed through research, the economics and marketing aspects were investigated before such technologies can be extended to industry practitioners. These were done for groupers raised in marine fishcages, tilapia raised in fishcages set in farm reservoirs, and for mudcrabs raised in pens set in mangroves.

Abstracts of the papers presented at the conference are cited individually.

A survey on the resistance patterns to selected antibiotics of bacterial pathogens of fish and shrimps in Panay Island, Philippines was conducted. One hundred and sixteen (116) bacterial isolates were collected from fish (Chanos chanos, Epinephelus sp. and Lates calcarifer) and shrimp (Penaeus monodon and P. indicus) tissues and rearing water. Among these isolates, only seven were identified as Aeromonas spp., the rest (109 isolates) were Vibrio spp., 42% of which were luminous Vibrio. Results of the sensitivity tests showed that all Aeromonas spp. isolates were resistant to streptomycin, oxytetracycline, and trimethoprim/sulphamethoxazole. Most of the Vibrio spp. isolates (94.5%) were resistant to streptomycin. Multiple resistance to two or more antibiotics was observed in 17 isolates of Vibrio spp. and all isolates of Aeromonas spp.

The morphology of Pseudorhabdosynochus lantauensis is described. It is the most numerous parasite recovered from the gills of cultured orange-spotted grouper Epinephelus coioides in the Philippines and is smaller compared with similar species reported in Hong Kong, Malaysia and Indonesia. This species is characterized by having an overlapping dorsal bar and short copulatory organ. The life cycle of the gill monogenean is also described. One mature parasite lays at least 10-22 eggs/day. Eggs are oval (0.021-0.120 mm) with a spiral filament attached to one end. Eggs hatch into free-swimming larvae (oncomiracidia) within 2-6 d at 30°C and 30 ppt. The rate of hatching of various eggs is highly variable, that is, some eggs hatch in 2 d while others take 6 d. The oncomiracidium can attach to the grouper host within 8 h. Upon attachment, the oncomiracidium metamorphoses to an adult parasite in 4-7 d. The parasite becomes fully mature and delivers eggs in 7 d. Without a host, the life span of oncomiracidium is only 4-8 h. The life cycle is complete in 13-20 days (eggs to oncomiracidium 2-6 d; oncomiracidium to adult parasite 4-7 d; adult to fully mature and egg delivery parasite 7 d). This is the first report on the morphology and life cycle of P. lantauensis from the Philippines.

The aims of this study were to establish an accurate size measurement method and a nutritional condition evaluation method of Holothuria scabra (Jaeger). Although 0.5% KCl and 0.05% MgSO₄ did not induce anaesthesia, 2% menthol–ethanol for 20 min was found to be effective and harmless. The anaesthetization significantly reduced the coefficient of variation of the mean body length and weight by 68% and 43% respectively. During starvation, body size and weight decreased concomitantly, resulting in an unchanged condition factor (body weight/volume), suggesting that the condition factor cannot be used as an index of nutritional condition. Protein, cholesterol and carbohydrate concentrations in the body fluid were analysed to study the relationship with starvation. As the protein and cholesterol concentrations initially increased and then decreased during the starvation period, it is difficult to use them as an index of nutritional condition. The carbohydrate concentration showed a gradual one-fold increase during 10 days of starvation, and it may be used as a proxy for nutritional condition; however, further physiological studies are needed. Body fluid density and volume relative to body size gradually increased and decreased, respectively, during starvation. These methods may be used to correctly monitor the conditions of H. scabra in studies for aquaculture and stock enhancement techniques.

White spot syndrome virus is the most important among the shrimp diseases. It has been devastating the shrimp industry for more than 3 decades. Previous studies reported that greater percentage of yellow colonies on thiosulfate citrate bile salt sucrose agar (yellow vibrios) in the rearing water, abundant supply of natural food such as Chlorella, and the use of the greenwater technology (GW) are some ecological ways of preventing WSSV outbreak. The aim of this study was to investigate the efficiency of the 3 systems against WSSV. Shrimp, experimentally infected with WSSV by feeding with WSSV positive shrimp carcass, was cultured in tanks using three treatments: with tilapia to simulate the GW, seeded with Chlorella, and with molasses added to enhance growth of yellow vibrios. Shrimp cultured in seawater served as the control. Survival was recorded and shrimp were analyzed for WSSV quantification using qPCR upon termination. Analysis showed no significant differences in shrimp survival at 120 h post infection in all treatments and the control. However, from the original viral load of 1.40 × 10¹ WSSV/mg sample, WSSV decreased and was significantly lowest in shrimp cultured using GW (7.0 × 10⁰), compared to the control (4.82 × 10⁵) and the other treatments (3.66 × 10⁵ for molasses added and 4.64 × 10⁵ for Chlorella seeded) in which viral load increased 4–5 times. Shrimp survival was highest in Chlorella seeded treatment and lowest in GW. Nitrogenous waste concentrations were lowest in molasses added water and highest in GW. Results suggest that the GW culture technology provides protection against WSSV while addition of molasses lowers nitrogenous waste concentration. The use of GW in combination with the addition of molasses for shrimp culture is suggested.

Intensification in the grow-out culture of high-value fish requires a large quantity of quality fingerlings. Fingerling production is a component of fish farming that comprises nursery and grow-out culture, and may be a commercial enterprise option for fish farmers with limited pond area. The nursery rearing of the Asian seabass Lates calcarifer (Bloch) was conducted in netcages inside a brackishwater pond. The fish were fed with two isocaloric, high-protein diets formulated at the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) and a control treatment: diets A (40.40% crude protein, CP) and B (46.17% CP), and trashfish (TF) as control. Hatchery-bred seabass early juveniles of two size groups (S₁, 4.0 ± 0.2 g; S₂, 2.40 ± 0.03 g) were stocked at 75–100 fish per m³ and given diets A or B at 6–10% of average body weight (ABW) d^-1, or TF at apparent satiation. Seabass given the formulated diets attained the desired size (≥ 20–40 g) after 45 d but not the fish fed with trashfish. Size and treatments showed significant effects on final ABW, although no significant interaction between these factors was shown to affect body weight. As expected, S₁ fish attained a significantly higher ABW (30.7 ± 18 g) compared with S₂ fish (20.7 ± 11 g) regardless of diet treatment. Seabass fed with trashfish exhibited significantly lower final ABW (6.6 ±1.6 g) than those fed Diet A (33.4 ± 6.5 g) or Diet B (37.1 ± 9.4 g). Fish size did not have any significant effect on specific growth rate (SGR), but diet treatments did. SGR was significantly better when either Diet A (5.2 ± 0.30) or B (5.4 ± 0.20) was used compared with the SGR of seabass fed with trashfish (1.7 ± 0.5). Although size and treatment did not show significant interaction on fish survival, the use of bigger seabass resulted in higher survival (89 ± 11%) compared with smaller seabass (80 ± 11%). Regardless of size, similar survival was attained in seabass fed Diet A (89 ± 6%) or B (95 ± 5%), significantly higher than that in seabass given trashfish (72 ± 6%). An interaction between size at stocking and diet treatment significantly affected protein efficiency ratio (PER). When S₁ fish was used, diets A and B gave similar PER. However, when S₂ fish was used, diet A gave significantly higher PER (2.49 ± 0.02) among the treatments (P < 0.05). Regardless of size, significant differences (P ≤ 0.05) were observed in the mean production cost, revenue and income among the three diet treatments. Moreover, post hoc analysis using Tukey’s HSD test further showed that use of diet B resulted in significantly higher revenue (PhP25,132.80) and income (PhP12,597.47) compared with the two other treatments. Trashfish treatment gave the least revenue (PhP 9,525.60) and negative income (- PhP 1,798.40). Production cost was not significantly different between diets A and B. Hence, diet B is the most economically viable and productive diet treatment. The low break-even price of fingerlings obtained for diet B showed that selling price can still be reduced to lower production cost in grow-out farming.

The manual discusses spawning tilapia (Oreochromis spp) in concrete tank hatcheries, hapa hatcheries in ponds and in lakes in the Philippines. Also included in the manual are a list of agencies involved in tilapia research, a glossary of technical terms, and useful references.