Interest in the culture of snappers, belonging to the family Lutjanidae, is increasing in Southeast Asia due to their relatively high market price. However, the fry needed for culture still comes exclusively from the wild. The anticipated demand for snapper fry has stimulated studies to develop methods of supplementing the natural fry supply. This paper evaluates the reproductive performance of wild-caught mangrove red snapper broodstock induced to spawn as part of a project to establish seed production techniques at SEAFDEC Aquaculture Department.

This paper provides a framework of conflict in small-scale fisheries and presents a case study of an island community in central Philippines. The following sources of conflict were identified: destruction of fishing gears, destructive fishing practices, and encroachment of commercial fishers into municipal waters. Mechanisms for resolution were found at the individual, group, village, and municipal levels.

The free essential amino acid levels in muscle of young Nile tilapia (Oreochromis niloticus) after feeding graded amounts of a corresponding test amino acid were measured in 9 separate experiments to determine if free amino acids indicate requirements for growth. Data were analyzed by the broken line regression method. Breakpoints for free threonine and free isoleucine were near the threonine and isoleucine requirements for growth. Breakpoints for free lysine, free histidine, and free valine were much higher than the lysine, histidine, and valine requirements for growth, respectively. Levels of other free essential amino acids in muscle behaved erratically or increased linearly as the dietary test amino acid increased. Amino acid requirements as estimated by levels of free essential amino acids in muscle did not consistently confirm amino acid requirements for growth of Nile tilapia.

Pond-reared Penaeus monodon males and females were sampled regularly over a 4 month period of length and weight measurments to the body and external reproductive organs; joining of the petasmata and the presence of sperm in the spermatophores and thelyca were also noted. Astrong linear relationship exists between body weight and length parameters, and between size of thelycum/petasma and carapace length (CL). Both the unification of petasmal endopodites and sperm presence in the spermatophores in males were first observed at Day 121 from stocking (CL 26.4 mm) while sperm was first noted in the thelycum of females at Day 125 (CL 28.6 mm). Male P. monodon with unified petasmata. In general, size were not significantly different between males and females over the culture period.

Serum samples were taken from gravid female catfish 0 to 24 h after injection of luteinizing hormone releasing hormone analogue (LHRHa) and pimozide (PIM) to monitor the serum steroid hormone levels during the off seasons (February) and the peak of the natural breeding period (August). A parallel study was also conducted to compare egg production, fertilization, hachuring and larval rates upon yolk resorption from spawn’s of hormone-treated fish. Serum E₂ levels were significantly different only with varying times after injection (PI); a marked increase occurred at 13 h, but the elevation was higher in fish induced to ovulate during the peak (16.8 ng/ml) than off season(7.7ng/ml). Hormone-treated fish showed higher serum testosterone (T) levels during the peak season (17-23 ng/ml) than those injected during the off season (10-20 ng/ml) at 4-12 h PI. Serum 17¤, 20ß-dihydroxy-4-pregnene-3-one (DHP) levels og hormone-treated fish during the off season were only about half the level (0.29 and 0.52ng/ml) of those treated with the same hormones during the peak season (0.54 and 0.9 ng/ml) at 8 and 12 h PI, respectively. Initial eggs size was larger in fish induced to spawn in August (1.54 mm) than in fish induced in February (1.49 mm). All fish ovulated when induced to spawn during the peak of the natural breeding period, but ovulation rate was only 60% when were injected during the off season. Egg production, fertilization, hatchery and survival rates were similarly much higher when gravid females were induced to spawn in August (88 eggs/g body weight, 97%, 73%, and 95%, respectively) than those spawned in February (20 eggs/g BW,36%, 20%, and 47%, respectively). Results indicate that more eggs and of better quality, higher levels of T and DHP were produced during the peak season.

Fragments of Gracilariopsis heteroclada weighing 10 g each were inserted in a polypropylene rope, suspended at different depths (25 cm, 50 cm and 100 cm below the water surface) and cultured with Lates calcarifer fingerlings (22-25 cm long and 158-252 g) in floating net cages from April to October. After seven months of culture, the specific growth rate of G. heteroclada was found to be influenced significantly (p ≤ 0.05) by the interaction of three factors: sea bass, water depth, and month of culture. Highest growth rate of Gracilariopsis heteroclada was recorded at 25 cm below the water surface during the month of April unaffected by the presence or absence of sea bass; while the lowest growth rale was observed at 100 cm during the months of September and October in the absence of sea bass. Approximately, 172 (dry) g m^-2 mo^-1 is produced from this culture system. The average length and weight of Lates calcarifer at the end of seven-month culture period was 35-39 cm and 565-741 g, respectively. Percentage weight gain/cage was 195-258, survival rate was 92-100%, and total fish production per cage was 6,780-9,637 g.

Recent advaces in the spontaneous and hormoneinduced breeding of caged sea bass (Lates calcarifer bloch, Family Centropomidae) are reviewed. Spontaneous spawnings follow a semilunar rhythm, with most spawings accurring in the evening of quarter moon. Independent of the Lunar-associatd rhythm, mature sea bass which have attained the critical oocyte size of 0.40 mm spawns after an injecton or implantation of luteinizing hormone-releasing hormone analogue (LHRHa) Pelleted LHRHa along together with methyltestosterone can advance sexual maturation and spawning in April-May, ahead of peak breeding in July-August. Depending on the pelleted or injected LHRHa dose, mature female sea bass spawns singly or consecutively over 4 evenings. LLHRHa-induced egg release peaks during the first day of a multiple spawning bout. Daytime injection of LHRHa stimulates spawning in the evening until dawn, while fish injected LHRHa at night induces spawning at daytime and releases fewer eggs compared to nighttime spawning. these results optimize the use of LHRHa to stimulate gonad maturation and spawning so that sea bass seed are made available for hatchery rearing and grow-out.

Epizootic ulcerative syndrome (EUS) is a disease of wild and cultured freshwater fishes in Asia and IndoPacific (Roberts et al., 1986; Lilley et al., 1992). In the Philippines, the first confirmed EUS outbreak is reported in Laguna de Bay in December 1985 to February 1986 (Llobrera and Gacutan, 1987). Since then, EUS has been observed annually in the lake during the coldest months of the year - December to February or March. The disease has spread throughout Luzon, affecting wild and cultured fishes in lakes, ponds, paddy fields, and rice fish systems (Bondad-Reantaso et al., 1992). In September to December 1990, EUS was recorded among brackishwater and marine fishes from a lagoon in northern Luzon (Reantaso, 1991). Although EUS is recognized as a regional problem, no definite primary causative agent has been established. Virus, fungi, bacteria, and parasites have been isolated in EUS-positive fishes, but none has been implicated as the primary pathogen (Roberts et al., 1993a & 1993b). Among the bacteria associated with EUS, Aeromonas hydrophila is consistently isolated in affected fishes from the Philippines (Llobrera and Gacutan, 1987; Torres et al., 1990; Lio-Po et al., 1992). This paper reviews the work done on the bacterial aspects of EUS in the Philippines.