Effect of Pseudomonas aeruginosa (MTCC 1688) on the tissue phosphatases activity on Macrobrachium rosenbergii (De Man)

A time course study on the endotoxin toxicity of the gram negative bacteria, Pseudomonas aeruginosa MTCC 1688 on the tissue phosphatases activity on the giant freshwater prawn, Macrobrachium rosenbergii was conducted. The results revealed marked elevation of both acid and alkaline phosphatase activity in the haemolymph and body muscle. The hepatopancreas showed reduced phosphatase activity compared to control. The enzymes, being non-specific in action and particularly the acid phosphatase being of lysosomal origin, their increase in muscle and haemolymph has pathogenic significance in the inoculum treated prawns.     

Metabolism of proline by the tiger prawnPenaeus esculentus

The distribution and fate of¹⁴C-proline were investigated in immature tiger prawns,Penaeus esculentus Haswell, collected in Moreton Bay, Cleveland, Australia, by trawling during 1986/1987. Initially the prawns were fed¹⁴C-proline in food pellets to follow the pathway of proline absorption and distribution in the body.¹⁴C-proline was also injected directly into the prawn to provide sufficient tracer to follow the incorporation of¹⁴C into other amino acids and into proteins. A comparison was made of the metabolism of injected¹⁴C-proline over 48 h in prawns that had been fed and those that had been starved for 10 d. Free amino acids (FAA) in the muscle and protein-bound amino acids were analysed separately. Labelled proline was completely absorbed and distributed within the body 3 h after ingestion, about 80% being in the tissues, mostly in muscle. There was no significant difference between the total CO₂ output in fed and starved prawns, but the latter metabolised about twice the amount of labelled proline over 48 h. At this time, in abdominal muscle of fed prawns, about 95% of the total muscle label was in the FAA; of the label in the FAA, 78% was proline and 18% glutamic acid, with the remainder in hydroxyproline, aspartic acid, glutamine, alanine and Kreb's cycle intermediates. In the starved prawns, proline was 58%, glutamic acid 24%, with correspondingly higher amounts in the other compounds. In the muscle protein, the distribution of label was similar in fed and starved prawns, with 72 to 74% as proline. The experiments showed that proline is not very labile in the tiger prawn and its rate of synthesis is slow. It does not appear to be an important source of energy as in some insects and cephalopods, but during starvation is only slowly oxidised for energy.     

Acute toxicity effect of the venom of the marine snail, Conus zeylanicus

Acute toxicity of the venom of Conus zeylanicus was studied to evaluate its risk and toxic factors in view of human safety The lethality of the crude venom (LD50 -60 mg/kg via i.p.) in mice was associated with increased heart rate and strong muscular hind limb paralysis, skeletal muscle paralysis, dyspnea, loss of spontaneous activity followed by respiratory failure. The effect on vital tissues revealed liver tissues were disrupted with hemorrhagic necrosis and the lung showed the pathogenic changes of diffused inflammation of the parenchyma and obliteration of the alveolar space. In brain, edema was observed throughout the parenchyma and the kidney shows the tubules with cloudyswelling of the lining cells and the parenchyma inflammation and few inflammatory cells infiltration.     

Contribution of mangrove detritus to juvenile prawn nutrition: a dual stable isotope study in a Malaysian mangrove forest

Dual stable C and N ratio analyses of primary producers and prawns have clarified the important role of mangrove detritus as the primary food source of juvenile prawns inhabiting the upper estuaries of the Matang mangrove swamp in Malaysia. The contribution of mangrove carbon to prawn tissues, as high as 84%, decreased in the offshore direction, as the contribution by phytoplankton became progressively more important. Prawns located 2 km outside the mangrove swamp still exhibited a dependency of 15–25% on mangrove carbon, but farther offshore (7–10 km) in shallow waters, the prawn's food was basically phytoplankton, with some contribution from benthic microalgae. Comparative stable C and N isotope ratios of tissue and gut contents indicate that prawns basically assimilated what they consumed. Received: 29 February 2000 / Accepted: 26 August 2000     

Effects of Hg and Cu on hemocytes-mediated functions in the prawn,Macrobrachium malcolmsonii

Sublethal effects of Hg (9.6, 14.5 and 24.1 microg/l) and Cu (60.5, 90.8 and 150.5 microg/l) on the hemocytes-mediated functions in the juveniles of the economically important freshwater prawns, Macrobrachium malcolmsonii were investigated. The population of total hemocytes, percentile phagocytosis and superoxide anion production were found to be increased in test prawns exposed to the lowest sublethal concentration of these two metals in comparison to controls. This indicates the fact that a mechanism of host-defence was in an active state to encounter metal toxicity. The total hemocytes population, percentile phagocytosis and superoxide anion production were found to be decreased in test prawns exposed to intermediate as well as the highest sublethal concentrations of Hg and Cu when compared with controls. This suggests that high concentrations of both Hg and Cu have inhibitory effects on the immune functions of the hemocytes in the prawn, M. malcolmsonii.     

An individual-based stochastic hazard model of eastern king prawn (Melicertus plebejus) migration with spatially and temporally varying fishing effort

This paper describes an individual-based stochastic model of eastern king prawn migration along the eastern Australian coast. Migration is treated as one-dimensional diffusion with drift. Capture of a prawn is seen as a failure event driven by movement through a spatially and temporally variable fishing mortality hazard. This hazard is combined with a uniform natural mortality hazard. We use a Monte Carlo method to estimate parameters by comparing expected numbers of tag-returns predicted from the model with previously published tag-release data. As the previous study used a discrete compartmental model, with compartments corresponding to zones of constant fishing effort, we used the same zones and fishing effort in our comparison. The marginal distribution of yield in each zone per single recruit is determined, providing more information compared with the deterministic approach to yield-per-recruit. Using our model we also derive the constant fishing mortality rate equivalent to a spatially variable fishing mortality rate in its impact on the proportion of prawns surviving the migration to reach spawning grounds. Determination of this proportion could contribute significantly to a sustainability assessment of the fishery. It is demonstrated using the AIC that better fits to the data of the previous study and greater parsimony are obtained using our model than were found in the deterministic compartmental analysis of that study. This improvement results from the ability of our model to account separately for average speed of movement and average dispersal rate, whereas in the previous deterministic compartmental model, movement is governed by just one parameter. Our individual-based model includes a parameter that explicitly accounts for dispersal of prawns in migration, so it can distinguish between speed effects and dispersal effects in the data. It also models both types of mortality as processes distinct from those of movement. This enables it to better separate movement and mortality effects compared to the compartmental approach, in which movement and mortality are treated as similar departure processes from a compartment. This separation reduces confounding of movement and mortality effects when parameters are estimated.     

Acute toxicity of copper sulphate to fresh water prawns

Fresh water prawns, Macrobrachium lamarrei and Macrobrachium dayanum (Crustacea-Decapoda) were subjected to static bioassay tests to ascertain the LC50 values of copper sulphate. The 24, 48, 72 and 96 hr LC50 values of copper sulphate for M. lamarrei were 0.38, 0.361, 0.343 and 0.300 mg/l and for M. dayanum were 1.634, 0.988, 0.532 and 0.418 mg/l respectively. Behavioral responses and LC50 values indicate that M. lamarrei were more sensitive to copper sulphate than M. dayanum.     

Carbaryl-induced alterations in biochemical metabolism of the prawn,Macrobrachium malcolmsonii

The present study was performed to investigate the toxic impact of carbaryl on biochemical metabolism in the hemolymph, brain, hepatopancreas, gills and muscle of intermoult juveniles of the economically important prawn, Macrobrachium malcolmsonii. The concentration of glutathione S-transferase (GST) was found to be higher in test prawns when compared with controls. This suggests that a mechanism of detoxification was in operation to neutralise carbaryl toxicity. However, the toxic effect of carbaryl was not fully neutralised, and hence, alterations were recorded in basic biochemical metabolism of test prawns. The concentration of acetylcholinestrase (AchE) was found to be lower in test prawns than that of controls. Carbaryl toxicity resulted in utilisation of major biochemical constituents, such as total carbohydrate, glycogen, protein and lipid to generate required energy as an attempt to withstand the toxic stress. Glycogenolysis resulted in elevation of total free sugar level in the hemolymph of test prawns. While proteolysis led to elevation of total free amino acid level in test prawns. The content of total lipid have also been found lower in test prawns than that of controls. This suggests that carbaryl toxicity resulted in severe energy crises in test prawns. In the present study, toxic effects of carbaryl impair basic metabolic functions and hence pose a threat to the life of M. malcolmsonii.     

The influence of rainfall on the distribution and abundance of the school prawn Metapenaeus macleayi in the Hunter River region (Australia)

The effects of rainfall on the distribution and abundance of Metapenaeus macleayi in the Hunter River region (Australia) were examined as part of a study of the prawn fishery and biology in this region. A marked increase in the freshwater flow into the estuary of the Hunter River enhances the seasonal seaward movement of prawns and produces an initial increase in the abundance of adults in the adjacent oceanic waters; it is suggested that the disturbance to the estuarine sediments and to the prawns' normal burrowing and respiratory activity, as a result of the increased river flow, is responsible for this pronounced emigration. This initial increase in adult abundance enhances the prawns' reproductive potential, and the heavy rainfall indirectly assists the recruitment of young to the cotuary and their growth and survival, and thereby increases prawn abundance in the following year also. Prolonged dry weather adversely affects the prawns, and usually results in a smaller population. The annual fluctuations and absence of a downward trend in the catch statistics indicate that this stock has not been overfished.     

Seagrass and algal beds as nursery habitats for tiger prawns (Penaeus semisulcatus and P. esculentus) in a tropical Australian estuary

We evaluated the importance of seagrass and algae to two species of tiger prawns (Penaeus semisulcatus and P. esculentus) by detailed sampling at four sites (two seagrass, two algae) in the Embley River estuary, and through sampling 26 sites in 7 adjacent estuaries at one time of year. Samples of tiger prawns were collected in the Embley River estuary with a small beam trawl at night every 2 wk from September to May for 2 yr (1990 to 1992). The two seagrass sites, which were 11 and 13 km from the river mouth, showed less seasonal variation in salinity than the two algal sites, which were 15 and 20 km from the river mouth. The algal beds at the two upstream sites almost disappeared during the wet season, but the biomass of seagrass did not change significantly between the wet and dry seasons. The grooved tiger prawn (P. semisulcatus), the main species at all sites, comprised 88% of the total tiger prawn catch over the two years. They were found at all sites during the pre-wet season, but after the onset of the wet season, they disappeared along with the algae, from the upstream sites. The brown tiger prawn (P. esculentus) was found almost exclusively (97% of the total catch) on the seagrass sites downstream. In the study of several estuaries, juvenile P. semisulcatus were caught at all 26 sites, and P. esculentus were caught in much smaller numbers, at 16 sites. Approximately equal numbers of P. semisulcatus were caught in seagrass and algal beds in the pre-wet season. Very few individuals >10 mm carapace length of either species, were caught. The results from this study highlight the importance of algal beds during the pre-wet season as nursery areas for one species of tiger prawn (P. semisulcatus).     

附生假单胞菌存在下不同光照时间对铜绿微囊藻生长与磷代谢的影响

通过设置8/16、12/12、16/8不同光暗比,分析了附生细菌存在下不同光照时间对铜绿微囊藻(M icrocystis aeruginosa)生长及其与附生假单胞菌(Pseudom onassp.)磷代谢之间关系的影响。结果表明:光照时间越长,铜绿微囊藻生长越快,16 h光照下的比增长速率为8 h光照下的1.6倍。铜绿微囊藻的快速生长促进了附生细菌中磷的释放;藻细胞增殖越快,附生细菌释放的磷越多。铜绿微囊藻对数生长期末,8、12、16 h光照下附生细菌磷含量分别降至对数生长初期的87.8%、78.6%和64.9%。铜绿微囊藻对附生细菌磷释放的促进作用是由藻细胞生长对磷的消耗再吸收导致的。     

Sub-lethal impact of carbaryl on food utilization in the freshwater prawn Macrobrachium malcolmsonii

This study determines the toxic effect of carbaryl (Sevin50% W.P) on the food utilization parameters in intermoult juveniles of the prawn, Macrobrachium malcolmsonii. The prawns (4.5-5.0 cm in length and 1.0-1.25 g wet wt.) were exposed to three sub-lethal concentrations of carbaryl (5.15, 7.73 and 15.47 microgl-1) for duration of 40 days. The toxic medium was renewed daily. The prawns were fed ad libitum with known energy quantity of boiled goat liver on daily basis. The overall wet weight gain was calculated. The energy lost through unconsumed food (15-60%), faeces (15-109%), ammonia excretion (9-27%) and moults (13-26%) of the prawns were calculated. The feeding rate, the rate and efficiency of absorption, the metabolic and food conversion rates and the gross and net food conversions efficiencies were found to be significantly declined (p<0.05) in test prawns when compared to that of the control. The energy lost through faeces, ammonia excretion and exuvia was found to be significantly elevated (p<0.05) in test prawns than that of the control. The effectof carbaryl on the bioenergetics parameters was severe in the highest sub-lethal concentration, less in the intermediate concentration and least in the lowest sub-lethal concentration. The results indicated that decrease in feeding, absorption, metabolism and food conversion are interdependent and toxicity of carbaryl diverting energy from production to maintenance pathways, which ultimately resulting in declined growth of M. malcolmsonii.     

Impact of malathion on the biochemical parameters of gobiid fish, Glossogobius giuris (Ham)

There is a dearth of information regarding the changes in heart muscle metabolites induced by pesticides. In the present study, the gobiid fish, Glossogobius giuris, was exposed to sub lethal concentrations of (0.05, 0.25 and 0.5 ppm) organophosphorus pesticide, malathion for short duration (24 to 96 hr). The cardiac muscles showed maximum depletion of glycogen and cholesterol content during 72 and 96 hr after treatment with 0.5 ppm malathion. Whereas a slight fluctuation of protein and glycogen content was observed in low concentration (0.05 ppm) of malathion. The levels of protein showed a significant decrease at high concentration (0.5 ppm) when treated for longer duration (96 hr). The present study reports metabolic dysfunction in response to malathion toxicity in the fish.     

Prevalence of Staphylococcus aureus and Pseudomonas aeruginosa in indoor air flora of a district hospital, Mandya, Karnataka

Two year (1998 and 1999) extensive survey was carried out in Mandya district hospital, Karnataka for a period of three years to monitor the prevalence of Staphylococcus aureus, Pseudomonas aeruginosa (S. aureus and Ps. aeruginosa) from the indoor air samples of operation theater labor room, children's ward, male and female general wards postoperative wards etc. A rotary air sampler loaded with manital salt and Pseudomonas selection agar media strips were used to collect the samples from various sites. The survivallence results revealed the prevalence of S. aureus and Ps. aeruginosa in almost all sampling sites, irrespective of season indicating their long-term survival and consequent threat to hospitalized patients as well the working employees.     

Profiles of acid and alkaline phosphatases in the prawn Macrobrachium malcolmsonii exposed to endosulfan

The present study was performed to determine the toxic effects of endosulfan on the quantitative and qualitative aspects of acid and alkaline phosphatases (ACP and ALP) in Macrobrachium malcolmsonii. Intermoult juvenile prawns were exposed to 32.0 ng/l of endosulfan for a period of 21 days. Samples were taken from the hemolymph, hepatopancreas, gills and muscle of test prawns on the 21st day. The content of ACP and ALP in the hepatopancreas of test prawns were found to be higher in comparison to respective controls. The levels of these enzymes in the hemolymph, gills and muscle of test prawns were found to be lower than in the same tissues of controls. In non-denaturing PAGE, phosphatases appeared as white bands. The intensity of white bands in the hepatopancreas of test prawns were found to be higher when compared to controls. In the hemolymph, gills and muscle of test prawns, the intensity of white bands were found to be lower in comparison to controls. The results of the present study suggest that endosulfan affects the quantity and quality of ACP and ALP in the tissues of M. malcolmsonii.     

Biomasses,catch rates and abundances of demersal fishes,particularly predators of prawns,in a tropical bay in the Gulf of Carpentaria,Australia

The demersal fish fauna of Albatross Bay, in the eastern Gulf of Carpentaria, northern Australia, was sampled on seven cruises from August 1986 to November 1988, using a random stratified trawl survey. Four depth zones between 7 and 45 m were sampled during both day and night. The mean biomass of fish from all seven cruises was 297 kg ha^–1 for days trawls and 128 kg ha^–1 for night trawls. The overall mean catch rates were 922 kg h^–1 for day trawls and 412 kg h^–1 for night trawls. There were marked differences between cruises in both the biomass and catch rate. Approx 890 000 fish of 237 species were collected. Of these, 25 species comprised 82% of the total biomass and 74% of the overall catch rate. The dominant families were Leiognathidae, Haemulidae and Clupeidae, with Sciaenidae and Dasyatidae important at night.Leiognathus bindus was the most abundant species. Twenty-five species occurred in more than 50% of trawls, withCaranx bucculentus the most frequently caught (96% of all trawls). Thirty four species were predators on prawns; their absolute mean biomass was 50 kg ha^–1 during the day and 39 kg ha^–1 at night. The corresponding catch rates were 171 and 125 kg h^–1. Multiple-regression analyses were used to discriminate the effects of diel, seasonal, depth and cruise patterns. Of the 31 most abundant species, 15 showed diel patterns of abundance; 11 species showed seasonal patterns of abundance; 23 species had differential depth distribution; and 13 species showed significant cruise-to-cruise variation in abundance. Cruise variations in abundance were tested against salinity, temperature, tidal exchange, plankton biomass and prawn abundances as well as periods (and lags) of total rainfall prior to sampling. Only total rainfall showed any significant correlation. Total rainfall over a period of 6 wk immediately prior to sampling showed significant positive correlations with the abundances of five species, with overall daytime catch rates, and with the suite of 34 prawn predators. Rainfall and river runoff into Albatross Bay were significantly correlated. In Albatross Bay, the complex of factors affecting fish abundances and the magnitude of between-cruise differences indicate that such tropical communities may be unpredictable and are not seasonally constant. The high catch rates in Albatross Bay relative to similar tropical areas elsewhere are discussed and attributed to the light exploitation of the Albatross Bay stocks. Other than a prawn fishery, there is no commercial trawling in Albatross Bay. Hence, the only fishing mortality is a result of by-catch from prawn trawling. The annual total of such fish by-catch is probably less than 10% of the estimated standing stock of 93 000 tonnes.     

Estimating the influence of prawn stocking density and seagrass type on the growth of juvenile tiger prawns (Penaeus semisulcatus): results from field experiments in small enclosures

Fine mesh enclosures (0.9 m² in basal area, 1 m high, with 100 µm mesh) and a jet-net retrieval system were developed to test the influence of juvenile prawn stocking density on growth rates in (1) different months (April and October/November) and (2) different types of intertidal seagrass beds in the Embley River estuary of tropical Australia. Small juvenile tiger prawns (3-6 mm in carapace length, CL) were stocked in enclosures at densities of 4-32 prawns per enclosure (4.4-35.5 prawns m^-2) on a high biomass seagrass bed (about 70 g m^-2 of mostly Enhalus acoroides) and one with low biomass (about 10 g m^-2 of mostly Halodule uninervis). After 2-3 weeks in the enclosures, recovery rates, and hence possibly survival, were greater on the high biomass Enhalus than on the low biomass Halodule. However, not all fish and crustaceans could be excluded from the enclosures. Growth rates were twice as fast on the high biomass Enhalus than on the low biomass Halodule. It is likely that the high biomass Enhalus, with its greater surface area, supported more epiphytic flora and fauna and reduced the potential for interference competition between prawns, compared with the low biomass Halodule. Growth rates on Enhalus were significantly faster at a stocking density of 4 prawns per enclosure (1.3 mm CL week^-1) than at a stocking density of 16 and 32 prawns per enclosure (both 0.8 mm CL week^-1), and did not differ significantly between April and October/November (temperatures were about 30°C at both times). The mean growth rate at 8 prawns per enclosure (1.1 mm CL week^-1) did not differ significantly from those at 4, 16 and 32 prawns per enclosure. These results from two seagrass beds suggest that the carrying capacity for juvenile tiger prawns was greater in the high biomass Enhalus than the low biomass Halodule bed.     

Monitoring acoustically tagged king prawns <Emphasis Type="Italic">Penaeus</Emphasis> (<Emphasis Type="Italic">Melicertus</Emphasis>) <Emphasis Type="Italic">plebejus</Emphasis> in an estuarine lagoon

Fine-scale movement patterns in penaeid prawns are rarely observed in situ, but are essential in understanding habitat use, foraging, and anti-predator behaviour. Acoustic telemetry was applied to examine the activity, space utilization, and habitat use of the eastern king prawn Penaeus (Melicertus) plebejus, at small temporal and spatial scales. Tracking of sub-adult P. plebejus (n = 9) in Wallagoot Lake (36.789°S, 149.959°E; 23 April–12 May 2009) and calculation of a minimum activity index (MAI) revealed high variation in activity rates across diel periods and in different habitats. Elevated activity rates and movement indicated foraging in unvegetated habitats during the night. Areas within the 95 and 50% space utilization contours averaged 2,654.1 ± 502.0 and 379.9 ± 103.9 m², respectively, and there was a significant negative relationship between these areas and prawn activity rates in unvegetated habitats. This study provides the first estimates of prawn activity rates and space utilization in the field. Application of acoustic telemetry can increase knowledge of prawn movements and their interactions with other marine species in different habitats.