40 resultados para Man-Machine Communications.


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Macrobrachiurn rosenbergii is one of the widely cultured freshwater prawn species globally. India was the third largest producer of this species in 2007 and its aquaculture production rose to 43,000 metric tons (t) in 2005 froin less than 500 t in 1995. However, since then production has been declining and in 2008-09 it was 12,856 t, a reduction of more than 70% compared to 2005. There are several contributing factors to this decline, such as slow growth rate, poor survival, disease outbreaks, increase in cost of production, and availability of low risk alternative fish species. However, there is a consensus that poor seed quality leading to unsatisfactory growth and survival rates in ponds is one of the major reasons. Hence, the development of a systematic selective breeding program aimed at improving growth rate and ensuring high survival rate of this species was deemed a high priority. The Central Institute of Freshwater Aquaculture (CIFA), Bhubaneswar, India in collaboration with the WorldFish Center, Malaysia initiated a selective breeding program for this species in 2007.

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Larvae of Macrobrachium rosenbergii were successfully reared in artificial sea water prepared in fresh ground water. The water was circulated through a biological filter by means of air-lift pumps for a period of one week to remove the undissolved particles prior to use in the hatchery operation. The experiments were initiated during 1989 and the hatchery has been working on pilot scale since June, 1990. The larvae in all the experiments were fed with egg-custard, Mona and Artemia nauplii. The survival rate varied from 5 to 52% in the 12 experiments. These findings can add to the development of hatcheries in the inland areas which can further boost the popularization of giant freshwater prawn farming.

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During 1964, the offshore fishing station, Cochin, took up a programme of exploratory tuna fishing in the deeper waters off Cochin. A side trawler was converted into a tuna long liner for this purpose.

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During the course of experimentations on the inducement of breeding in Macrobrachium rosenbergii (De Man) under laboratory conditions, detailed observations on the mating behaviour of the species have been made, which have been elaborated in this account. Various behaviour patterns have been analysed critically and the probable directive and releasive factors for these behaviour patterns discussed. Differences in behaviour of the male resulting from the introduction of another mature male in the arena have been described. An aberrant displacement activity which has been observed in one of the males has also been discussed.

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An experiment was conducted in two phases for 45 days each to study the effects of six stocking densities (phase-I: 100, 200 and 300 PL/m² and phase-II: 250, 500 and 750 PL/m²) on growth and survival of Macrobrachium rosenbergii postlarvae (PL) in nylon hapa-nets (1.8m x 1.8m x 1.4m) installed in a pond. Stocking densities of 100, 200 and 300 PL 10/m² resulted in similar (P<0.05) body length (47-48 mm) and survival rate (84-88%), while body weight (0.62g) in PL with 300/m² was significantly lower than that (0.70g) in PL with 100 and 200/m². The growth (body length 47mm and weight 0.64g) and survival (84%) of PL stocked at 250 PL/m² density were significantly higher (P<0.05) than that of PL at 500 and 750/m². Besides the variation in growth and survival in PL at six tests stocking densities, a sharp increase in body weight of PL was observed beginning at the 4th week of rearing.

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Total bacterial load in the haemolymph of freshwater prawn Macrobrachium rosenbergii varied from 6.2x10⁴ to 1.9x10⁷ CFU/ml whereas in the hepatopancreas, bacterial load varied from 1.9x10³ to 2.9x10⁵ CFU/g. The total bacterial load in the pond water varied from 2.6x10² to 4.1x10⁵ CFU/ml. The isolated bacterial genera in the haemolymph and the hepatopancreas of prawn were Streptococcus, Acinetobacter, Micrococcus, Aeromonas, Vibrio, Flavobacterium, Staphylococcus and Pseudomonas, whereas the detected bacterial genera in pond water were Micrococcus, Streptococcus, Vibrio, Flavobacterium, Staphylococcus, Pseudomonas and Aeromonas. Among the detected genera, Vibrio and Staphylococcus were found to be dominant genera in the haemolymph of the sampled prawn throughout the study period whereas Staphylococcus and Pseudomonas were dominant in pond water.

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An experiment was conducted for 105 days in 12 earthen mini ponds of each 30m² size. Five different experimental diets containing 32% protein were formulated and prepared using fishmeal, shrimp meal, soybean meal, mustard oil cake, sesame meal, wheat bran and rice bran. A commercial shrimp diet (SABINCO starter-III) was assigned to treatment six and considered as the control. Prawns were stocked at the rate of 2.5 fry/m² and feed twice daily at the rate of 10% at the beginning and reduced to 8% for the last two months. The results of the experiment showed that prawn fed diets 1, 2, and 6 (control) showed significantly (P<0.05) highest weight gain among the dietary groups, while prawn fed diet 5 showed significantly lowest weight gain. The FCR values of diets ranged between 3.06 to 4.85. Prawns fed diet 1 and 6 showed significantly higher SGR, survival (%) and production among the dietary groups. The survival (%) of the prawns ranged between 46.6 to 66.6% and the production ranged between 304.5 to 563.3 kg/ha/105 days. The result of the study showed that diet containing 30% fishmeal, 5% shrimp meal, 5% soybean meal, 10% mustard oil cake, 10% sesame meal, 20% wheat bran, 18% rice bran, 1% oyster shell and 1% vitamin premix may be recommended for monoculture of M. rosenbergii.

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Distribution of post larvae, juveniles and adults of Macrobrachium rosenbergii was studied in three rivers of Paikgachha, Khulna during November '91 to Apri1 '94. The adults were found to ascend upstream and the matured ones again return to the estuary to breed. Post larvae of M. rosenbergii prefer a salinity range in between 0.5 to 19.0 ppt and juveniles require a salinity range in between 0.0 to 2.0 ppt.

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Cultured Macrobrachium rosenbergii (Scampi; 30-40 g) in headless shell-on form was stored in ice (Prawn:ice=1:2) in a plywood box insulated with 2 cm thick expanded polystyrene and subjected to detailed examination of quality by chemical, microbiological and organoleptic evaluation at regular intervals to assess the storage life. The prime quality life of prawns in ice was found to be 8 days followed by a phase of lowered quality, but still acceptable till the end of 13 days.

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Cultured Macrobrachium rosenbergii (Scampi, about 30 g each) in headless shell-on form was individually quick frozen in a spiral freezer. The frozen samples were glazed and packed in polythene bags, which were further packed in master carton and stored at -18°C. Samples were drawn at regular intervals and subjected to biochemical, bacteriological and organoleptic analysis to study its storage characteristics. The data on the above parameters showed that the samples were in prime acceptable condition when stored up to 23 weeks. No appreciable change in colour and odour was noticed in the raw muscle. Afterwards, organoleptic evaluation of the cooked muscle revealed slight change in the flavour. Texture also appeared little tougher. These changes in organoleptic characters were well supported by the biochemical bacteriological changes in the muscle.

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Effects of three different doses of vitamin D sub(3) on molting, growth, and calcium and phosphate composition of tissue and molt during the grow-out of the giant freshwater prawn Macrobrachium rosenbergii (average weight 10.56 ± 0.20 g), obtained from a grow-out pond, were studied. Intramuscular doses of vitamin D sub(3) (100, 500 and 2000 IU/kg body weight) were given on the 1st, 3rd, 5th, 7th, 9th, 11th, 13th, 15th, 20th, 25th and 30th days. All the experimental animals were fed with a basal diet containing fish meal, shrimp meal, wheat flour, groundnut de-oiled cake, soybean meal and wheat bran at 3% of the body weight. The numbers of molts were recorded as 20±0.50, 29±1.16, 51±1.87, and 30±1.60 in control, 100, 500 and 2000 IU/kg body weight physiological doses, respectively. Maximum growth was recorded in prawns given 500 IU/ kg dose. Survival was between 58.33 ± 9.13 and 77.77 ± 8.61%. The ash content and calcium level increased significantly (p<0.05) and recorded the highest values in 500 IU/kg physiological dose. However, the inorganic phosphate (P sub(i)) content recorded the highest values in tissue in 2000 IU/kg dose (p<0.05, F = 50.60613). There is no significant difference in calcium contents (p>0.05) in both tissue and molt at 500 and 2000 IU/kg doses. It was found that a higher physiological dose (2000 IU/kg) of vitamin D sub(3) increased the rate of mortality. Results have shown that vitamin D sub(3) has a positive impact on the growth and survival of M. rosenbergii and it interferes with the metabolism of Ca and P sub(i), in tissue, and alters molting frequency. Results on physiological dose suggest an alternative and effective dietary supplementation method of vitamin D sub(3) in the grow-out phase of M. rosenbergii.

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Morphometric characteristics of Lamellidens lamellatus were studied using a random sample of 138 individuals collected from Bathalagoda reservoir in Kurunegala district. The largest number of individuals in the collection was between 40-50 mm in length. They had a body weight between 60-80 gm. The most abundant bio-chemical component in the adductor and in the foot was protein. Carbohydrate and lipid quantities were almost equal while ash showed the least value. The total protein content ranged from 48.8% to 73.4%; the carbohydrate content from 12.64% to 23.8%; and lipid content from 12.0% to 28.1% of their dry weight. It was found that there were significant relationships between the length and the body weight; and between length and volume.

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An incidence of bopyrid isopod infestation was observed in giant freshwater prawn, Macrobrachium rosenbergii (de Man) juveniles (40-60 mm/0.9-1.5 g) in a scampi culture farm in East Godavari district of Andhra Pradesh. The presence of parasite was observed by conspicuous boil like swelling of the branchial chamber where the parasite was found lodged on the gills. The infested gill was highly compressed and necrosed. Only one branchial chamber was infested by the parasite while the other gill was normal. The infested prawns were thin and emaciated and showed retarded growth. The parasite was identified as Probopyrus bithynis (Richardson, 1904) which caused inhibition of ventilation due to its permanent lodging in the branchial chamber and impaired the gaseous exchange by gills. It was also observed that this parasite caused parasitic castration in the infested prawns.