Sompop Rungsupa

Gonadal maturation and reproductive performance of giant tiger prawn (Penaeus monodon Fabricius) from the Andaman Sea and pond-reared sources in Thailand☆

Abstract Broodstock trials were conducted with Penaeus monodon to compare the gonadal maturation and reproductive performance of four combinations of broodstock: wild-caught, pond-reared, and two groups of cross-matings between wild-caught and pond-reared. Wild-caught broodstock were captured from an off-shore area of the Andaman Sea. The average weight of wild-caught females was almost double that of pond-reared females. Wild-caught broodstock produced significantly greater numbers of eggs than pond-reared broodstock, despite comparable egg quality. Cross-matings between broodstock from the two sources did not improve gonadal maturation or reproductive performance.

Groundwater Discharge as an Important Land-Sea Pathway into Manila Bay, Philippines

Abstract A multidisciplinary approach was taken to assess the potential importance of groundwater seepage to nutrient inputs into Manila Bay, Philippines. Three lines of seepage meters were installed in transects along the coast at Mariveles, Bataan Province, during the period 8–10 January 2005. The overall average seepage flux was 5.1 ± 5.4 cm d−1 (n = 73) with a range of 0–26 cm d−1 and a calculated integrated shoreline flux of 12.4 m3 m−1 d−1. Additional methodologies employed included automatic seepage meters, resistivity measurements, sampling for nutrient analyses in both seepage meters and ambient seawater, and use of natural radon as a groundwater tracer. Seepage meter and tracer results provided consistent results of estimates of submarine groundwater discharge into Manila Bay. Many lines of evidence suggest that seepage fluxes are not steady state but are modulated by the tides. Resistivity profiles show that the saline-freshwater interface moves on a tidal timescale, consistent with the observed drop in salinity of the seepage waters as low tide approaches. Our results show that dissolved inorganic nitrogen (DIN) fluxes via submarine groundwater discharge are comparable in magnitude to DIN fluxes from each of the two major rivers that drain into Manila Bay.

An improved, closed seawater recirculation maturation system for giant tiger prawn (Penaeus monodon fabricius)

A large, closed seawater recirculation system for maturation of giant tiger prawns is described. The system consisted of a circular, 7-m diameter, flat-bottom maturation tank (1·4 m water depth), and a separate bio-filter tank. During operation, water recirculation was four times daily. The system was housed in a building with light intensity 5% of ambient. Eight prawn maturation trials were conducted with this system. Each trial normally ran for three months with stocking densities of 3 prawns/m2. Prawn sizes ranged from < 100 to 200 g. Water quality was maintained at optimal condition throughout the trials. Maturation and spawning success appeared dependent on prawn quality and food quality provided.

Maturation and larviculture of penaeid prawns in closed recirculating seawater systems

The maturation and larviculture of giant tiger prawns (Penaeus monodon Fabricius) and banana prawns (P. merguiensis de Man) were studied in two types of closed recirculating seawater systems (closed systems), and in a seawater system with daily water exchange (open system). One closed system consisted of a 6 m3 rectangular tank with filters at both ends of the tank. The second closed system of a new design consisted of a 30 m3 circular tank with a filter at the center of the tank. Penaeus monodon maturation in these culture systems was comparable. Although egg production rates in the open system was higher than for the closed system, nauplii production rates were similar. With P. merguiensis, the open system gave greater production of post larvae (P20), although the water quality in the closed systems was much better than with the open system.

Event-based feature extraction for analyzing the first damage of coral under temperature and light intensity stressor

This paper deals with event-based feature extraction to analyze the incubation time of coral under two stressor: temperature and light intensity. The study is conducted in Kho Sichang Island, Thailand during hot season. The method for extracting the important events is Hilbert Huang Transform (HHT). The event as a result of Empirical Mode Decomposition (EMD) and Instantaneous Frequency (IF) are confirmed with the time duration of first symptom appearance in Acrophora Hummilis coral. The result shows variation of incubation time of coral disease under different event combination. The important finding in this research is incubation time of coral disease under different situation. It is important for early warning in coral damage.