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Materials and methods Design of experimentThe experiment was conducted in 6 high density polyethylene (HDPE) lined ponds (300 m 2 ) at King Abdulaziz University (KAU) Fish Farm, Faculty of Marine Sciences, Obhur, Jeddah for a period of 96 days. Semi-intensive type of culture method was followed for rearing shrimp. Both control and treatment experimental ponds were triplicated. All ponds were sundried and limed ABSTRACT A study was conducted to assess the efficiency of green water culture strategy for production of Pacific white shrimp Penaeus vannamei (Boone, 1931) in high density polyethylene (HDPE) lined ponds (300 m 2 ) for a period of 96 days. Green water from a broodstock fish pond was used for rearing shrimp in treatment ponds; whereas, filtered seawater was used for growing shrimp in control ponds, with both treatment and control in triplicates. Shrimp juveniles (specific pathogen free, SPF) of uniform size (1.74±0.46 g) were stocked at the rate of 100 nos. m -2 per pond. Feeding, water exchange, sampling and water quality analysis were done as per standard shrimp growout procedure. Shrimp health status and microbial load in culture ponds were recorded periodically. Water quality parameters did not show significant variations between control and treatment ponds. Enhanced growth, survival (19.7%) and biomass (23.3%) were observed in treatment ponds when compared to control. Significant reduction in bacterial population and improved shrimp health status were also noticed in treatment ponds. Green water culture technique reduced harmful bacterial population in culture ponds and enhanced shrimp growth, survival, health and production.

A study was conducted to assess the effect of UV-B solar radiation on plankton community, chlorophyll-A and β-carotene of pacific white shrimp, Litopenaeus vannamei cultured in HDPE liner ponds. There were control (ponds exposed to sunlight) and treatment (ponds shaded for 50% sunlight filtration) for the study and intensive shrimp culture was done in the ponds. UV-B radiation, physico-chemical parameters of pond water, Chlorophyll-A in phytoplankton and plankton community were monitored during the period. Significant (p<0.01) reduction in UV-B radiation was found in treatment ponds when compared to control with an average reduction of 23.2% at surface water due to solar filtration. Among plankton, Chlorophytes and diatoms were found to be lowered in control ponds. Dinoflagellate did not show significant difference between control and treatment, whereas Cyanophyte population decreased in increased solar radiation. Chlorophyll content in phytoplankton and shrimp β-carotene was found to be increased in treatment ponds. Significant effect was noticed on plankton growth and distribution due to UV-B radiation. However, it did not influence growth of shrimp in culture ponds.

Asian Seabass Lates calcarifer is widely used for pond and cage culture practice in the Kingdom of Saudi Arabia. A studywas carried out to understand the influence of an exogenous androgen, Testosterone propionate (TP) on milt quality ofL. calcarifer. Intramuscular injection of TP at dose 1.0 ml kg-1 was given to mature male fishes grown in a brood stockpond. A control was also maintained without giving hormone injection. After 36 h of injection, milt was collected and miltquality was assessed for colour, sperm cell concentration, motility and viability of spermatozoa. Short-term preservation ofmilt was carried out in oxygen and marine teleost Ringer’s medium at 4oC for 120 h. No significant change was observedin colour and pH of milt, but nature of milt changed from thick to watery due to hormone injection. Enhanced milt volume(14%) and sperm cell concentration (4%) was noticed in fishes from the treatment group 36 h post-injection, when comparedto control. Sperm motility duration and percentage motility were high in treatment fishes than control. Milt preserved inoxygen medium showed high sperm motility and viability when compared to Ringer’s medium. Intramuscular injection ofTP at 1.0 ml kg-1 improved milt volume and quality and therefore can be used for induced breeding of Asian Seabass. Keywords: Asian Seabass, Hormone, Intramuscular injection, Milt quality, Ringer’s medium, Sperm motility, Testosteronepropionate