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Argyrosomus Japonicus (Argyrosomu + japonicu)
Selected AbstractsEffect of short term exposure to the anaesthetic 2-phenoxyethanol on plasma osmolality of juvenile dusky kob, Argyrosomus japonicus (Sciaenidae)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2008A. K. Bernatzeder Summary The plasma osmolality of early juvenile dusky kob, Argyrosomus japonicus, exposed to 2-phenoxyethanol and control fish that were pithed prior to sampling, was investigated. Exposure to 2-phenoxyethanol, after 2, 4, 6, 8 and 10 min, did not alter plasma osmolality (Friedman test; P = 0.976). There was no significant relationship between the size of fish within the range 133,170 mm SL (40,85 g) and plasma osmolality. Finally, there was no significant difference in plasma osmolality between anaesthetized fish and the control group that were pithed directly after removal from the tanks. Anaesthetizing juvenile dusky kob with 2-phenoxyethanol prior to blood sampling did not affect plasma osmolality. [source] Synopsis of biological, fisheries and aquaculture-related information on mulloway Argyrosomus japonicus (Pisces: Sciaenidae), with particular reference to AustraliaJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2008V. Silberschneider Summary Argyrosomus japonicus is a member of the family Sciaenidae, which are commonly known as drums and croakers. A. japonicus occurs in estuarine and nearshore Pacific Ocean and Indian Ocean waters surrounding Australia, Africa, India, Pakistan, China, Korea and Japan. The biology of A. japonicus is relatively well studied in South Africa, and more recently studied in Australia, but no information is readily available from other areas of its distributional range. The early life history distribution of A. japonicus may differ among regions, with their distribution in estuaries linked to salinity, turbidity, freshwater flows and depth of water. Studies in South Africa and Australia found that juvenile fish grow rapidly, attaining 35 cm TL in 1 year and 87,90 cm TL in 5 years. Sexual maturity also differs among regions and is attained at 2,3 years of age and >50 cm in eastern Australia, 5,6 years of age and >80 cm TL in western Australia and southern Africa. The maximum reported length and age of A. japonicus is 175 cm and 42 years, respectively. Spawning most likely occurs in nearshore coastal waters although there is evidence to suggest that it may also occur in the lower reaches of estuaries. Time of spawning varies among geographic localities and is probably linked to water temperature and oceanography. Juvenile fish (<2 years) appear to be relatively sedentary, but sub-adults and adults can move relatively long distances (>200 km) and such movements may be linked to pre-spawning migrations. A. japonicus is important in many recreational and commercial fisheries, but like other sciaenids, is prone to overfishing. It is classified as recruitment overfished in South Africa and overfished in eastern Australia. Although much research has been done to minimize the capture of juveniles in Australian prawn-trawl fisheries, greater protection of spawners and improved fishing practices to enhance survival of discarded juveniles, particularly from prawn trawling, may be required. An aquaculture industry is developing for A. japonicus in Australia and preliminary research on the impacts and success of re-stocking wild populations has begun in an attempt to arrest the apparent decline in populations. [source] The interactive effects of dietary protein and energy on feed intake, growth and protein utilization of juvenile mulloway (Argyrosomus japonicus)AQUACULTURE NUTRITION, Issue 1 2010I. PIROZZI Abstract The objectives of this study were to describe the interactive effects of varying digestible protein (DP) and digestible energy (DE) contents on the feed intake, growth, protein utilization and whole body composition of juvenile mulloway (Argyrosomus japonicus) and to determine the optimal DP : DE ratio for growth. This was achieved by feeding mulloway diets containing one of four different DP levels (250,550 g kg,1) at two DE levels (16 or 21 MJ kg,1). Juvenile mulloway were stocked at each of two different sizes (70 or 200 g) in triplicate groups for each dietary treatment and fed twice daily to apparent satiation over 58 days. The results indicated that feed intake was not governed solely by energy demands but was also dependant on the DP content of the diet. Protein utilization did not improve with diets containing decreasing protein and increasing lipid content indicating that mulloway have a limited capacity to spare DP. Optimal DP content was found to be 444,491 g kg,1 depending on the DE content of the diet and the size of mulloway and is within the range reported for other sciaenid species. The use of formulated diets with 28.6 g of DP MJ DE,1 will achieve optimal growth and protein deposition for 70,275 g mulloway. [source] Weaning requirements of larval mulloway, Argyrosomus japonicusAQUACULTURE RESEARCH, Issue 10 2010Debra A Ballagh Abstract Mulloway (Argyrosomus japonicus) is an emerging aquaculture species in Australia, but there is a need to improve the production technology and lower costs, including those associated with larval rearing and live feeds. Three experiments were conducted to determine appropriate weaning strategies from live feeds, rotifers (Brachionus plicatilis) and Artemia, to cheaper formulated pellet diets. Experiment 1 examined the effects of feeding Artemia at different levels [0%, 50% or 100% ration of Artemia fed from 18 days after hatching (dah); based on current hatchery protocols] and a pellet diet from two larval ages (14 or 23 dah). In addition, rotifers were supplied to larvae in all treatments for the duration of the experiment (14,29 dah), at which time all larvae were successfully weaned onto the pellet diet. No significant (P>0.05) differences existed between the growth of fish fed a 50% and 100% ration of Artemia; however, fish fed a 0% ration of Artemia had significantly (P<0.05) reduced growth. The time of pellet introduction had no significant (P>0.05) effects on the growth of larvae. Experiments 2 and 3 were designed to determine the size [total length (TL), mm] at which mulloway larvae selected Artemia equally or in preference to rotifers, and pellet (400 ,m) equally or in preference to Artemia respectively. Each day, larvae were transferred from a holding tank to experimental vessels and provided with rotifers (2 mL,1), Artemia (2 mL,1) or a combination of rotifers (1 mL,1) and Artemia (1 mL,1) (Experiment 2), and Artemia (2 mL,1), a pellet diet or a combination of Artemia (1 mL,1) and a pellet diet that was broadcast every 15 min (Experiment 3). After 1 h, a sub-sample of larvae was randomly selected from each replicate vessel (n=5) and the gut contents were examined under a light microscope. Mulloway larvae began selecting Artemia equally to rotifers at 5.2 ± 0.5 mm TL and selected pellets equally to Artemia at 10.6 ± 1.8 mm TL. Our results have led to the establishment of weaning protocols for larval mulloway, which optimize larval growth while reducing feed cost by minimizing the amount of Artemia used during production. [source] | ||||||||||