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Aim of study: To evaluate the biomass production of green bean (Phaseolus vulgaris) in a media-filled aquaponics system together with Genetically Improved Farmed Tilapia, GIFT (Oreochromis niloticus). Area of study: Kota Kinabalu, Sabah (Malaysia). Material and methods: The experiment involved modulating and optimizing the density of extractive species (plants) in the hydroponic tank (55 cm × 35 cm). Five treatments were carried out: T0 (control-without plant), T2 (2 plants), T4 (4 plants), T8 (8 plants), T12 (12 plants) where the stocking density of GIFT was 30 tails (identical in all the treatments). Water volume in each treatment was 800 L and the experimental set up was closed recirculating type. The trials were carried out over a period of 90 days. Main results: Growth of the GIFT was not affected by the presence of green bean or by manipulation of the stocking density. Treatment T4 yielded significantly higher biomass production of green beans (1556.4 ± 88.9 g), compared to T2 (1083.6 ± 86.9 g), T8 (404.6 ± 47.9 g), and T12 (401.8 ± 98.1 g). There were noticeable fluctuations in the concentrations of NH3-N (ammonia), NO2-N (nitrite), NO3-N (nitrate) and PO4-P (phosphate) over the experimental period that indicated the process of nitrification and absorption of nutrients. Research highlights: The nitrogenous waste produced by the fish supported the biomass of the green beans in the aquaponics system and the waste uptake of this extractive species is effective enough for reuse of the water for rearing of GIFT.

The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method of biodiesel production from wet microalgae biomass is compared with the conventional water bath-assisted solvent extraction. The microwave irradiation extracted more lipids and high biodiesel conversion was obtained compared to the water bath-assisted extraction method due to the high cell disruption achieved and rapid transesterification. The total content of lipid extracted from microwave irradiation and water bath-assisted extraction were 38.31% and 23.01% respectively. The biodiesel produced using microwave irradiation was higher (86.41%) compared to the conventional method. Thus microwave irradiation is an attractive and promising technology to be used in the extraction and transesterification process for efficient biodiesel production.

Steady increase of fishmeal price due to unreliable supply of fish meal in the world market, coupled with increased demand have led aquaculture nutritionist to search for cheaper and sustainable alternative protein sources that can be incorporated in formulated diets. Green water which consists of green microalgae (mainly Chlorella sp.) can be produced easily in freshwater fish culture tank. Dried green water or green water meal GWM contains relatively high crude protein making it a potential candidate for fishmeal substitution. In the present study, the potential of GWM as a substitute of fish meal in the diets of Pacific white shrimp (Litopenaeus vannamel) was evaluated through two feeding trials. In Feeding Trial 1, five isoproteic and isolipidic diets with 0% (control diet), 10% (GWM10), 20% (GWM20), 30% (GWM30) and 40% (GWM40) GWM replacing fishmeal protein were fed to triplicate groups of shrimp, with an average initial weight of 1.73±0.003g and cultured in a flow-through tank culture system. The shrimps were fed by hand three times daily with amount 7-10% of their body weight for 44 days. In general, growth of the shrimp decreased with increasing level of GWM substitution. Although the 10% replacement of GWM (GWM10) caused significantly lower final body weight (FBW) and weight gain (WG) (P<0.05) compared with the control diet, the dry feed intake (DFI), feed conversion ratio (FCR), and specific growth rate (SGR) of this diet were not statistically different (P>0.05) from the control diet. In Feeding Trial 2, diets were formulated using the same speCification with diet's formulation in Feeding Trial 1 and fed to bigger size shrimps with an average initial weight of 6.42±0.02g and fed at 5-7% of their body weight daily for 56 days to investigate if larger shrimp has better tolerance than the smaller shrimp to GWM as dietary protein source. Similar growth trend with Feeding Trial 1 was observed in this trial. However, shrimp fed diet GWM10 did not show any signi

Larvae and juveniles of barramundi Lates calcarifer (Bloch) were examined for the development of the retina, occurrence of the retinomotor response and retinal tapetum and change in eye size with age in days. The barramundi hatched with unpigmented non-functional eyes in which retinal cells had not yet differentiated into the various elements. Soon it was followed by rapid changes in the histology of the retina. Two-day-old larvae had a well-pigmented retina with area temporalis which would allow acute vision and prey attack in the nasal direction. At 10 days, rod cells and the retinal tapetum first appeared in the retina and the retinomotor response first occurred; these would allow feeding in dim light. The retinal tapetum moved in unison with the cones and the pigment epithelium during the retinomotor response. At 26 days, the horizontal cells were divided into two layers and the twin cones appeared. These changes in the eyes occurred concurrently or in anticipation of behavioural changes, such as the onset of the first feeding at 2 days, the shift of habitat from coastal waters to swamps at the notochord flexion stage at 7-15 days, the abrupt change in feeding behaviour from roving zooplanktivore to lurking predator at 25-30 days and a later shift of habitat from turbid swamps to open coastal or lake areas at the early juvenile stage.

This study was conducted to clarify the development of free neuromasts with growth of the barramundi, Lates calcarifer. A pair of free neuromasts was observed behind the unpigmented eyes in newly hatched eleutheroembryos with a mean total length of 1.93 mm, and two-hour-old eleutheroembryos could respond to an approaching pipette. At 2 days after hatching, the egg yolk sac was mostly consumed, the eyes were pigmented, and the larvae commenced feeding on rotifers. Free neuromasts increased in number with growth and commenced developing into canal neuromasts in barramundi 15 days old with a mean total length of 8.07 mm. The average length of the major axis of the trunk free neuromasts attained approximately 12.9-15.5 μm, and the number of sensory cells was 15.4-17.5 at 15-20 days old. Developed cupulae of free neuromasts were observed in 1-day-old eleutheroembryos. The direction of maximum sensitivity of free neuromasts, determined from the polarity of the sensory cells, coincided with the minor axis of the lozenge-shaped outline of the apical surface of the free neuromasts. The polarity of trunk neuromasts was usually oriented along the antero-posterior axis of the fish body, but a few had a dorso-ventral direction. On the head, free neuromasts were oriented on lines tangential to concentric circles around the eye. © 2007 Zoological Society of Japan.