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Astaxanthin is a ketocarotenoid that is the primary pigment in shrimp and has powerful biological effects. This molecule comprises a 40-carbon chain with multiple double bonds at the end that connects to ketone and hydroxyl groups. The terminal hydroxyl groups can react with fatty acids and form monoester and diester of astaxanthin. Shrimp waste is an inexpensive source of this compound, whose extraction and purification can improve the economy of fishery production and processing in addition to solving the problem of shrimp waste disposal. The efficiency of astaxanthin extraction from Penaeus semisulcatus and Penaeus merguensis wastes was compared for the first time in the present study, employing the fermentation process with two strains of Lactobacillus acidophilus and Lactobacillus plantarum bacteria. The extraction conditions and effects of various treatments on astaxanthin yield were then adjusted using a Box-Benken design with three parameters: fermentation temperature (30–40 °C), fermentation time (12–72 h), and specifically by modifying the waste particle size (40–60 mesh). Following purification of the pigment, H-NMR and FT-IR spectroscopies, as well as Rf values, were clearly utilized to identify the astaxanthin present in the waste. The findings demonstrated that P. semisulcatus shrimp waste had considerably greater extraction yield with both bacterial strains than P. merguiensis shrimp (p<0.05). Also, L. plantarum bacteria had a higher ability to create better fermentation conditions and, as a result, higher extraction of astaxanthin from both shrimp species. Optimum conditions for this bacterium include a fermentation temperature of 35°C, a time of 72 h, and a particle size of 80 mesh. The Rf value for mono (0.59) and diester (0.76) of astaxanthin obtained were in accordance with international standards. FTIR analysis determined the recognizable peaks of mono and diester of astaxanthin, including hydroxyl functional groups and the vibrational mode related to its ester at the end of the polyene chain of astaxanthin. Also, an examination of H-NMR data showed the presence of indicative protons related to astaxanthin and fatty acids attached to it in the chemical shift regions of the spectra of extracted astaxanthin esters. [ABSTRACT FROM AUTHOR]

Mangroves are traditionally considered to provide important nutrition to tropical estuarine consumers. However, there is still controversy about this, and the extent and importance of these inputs are largely unquantified. In particular, there is no information for food webs of small estuaries that dominate wet-dry tropical coasts, where freshwater inflow is intermittent, leading to highly seasonal inputs of nutrients from terrestrial systems. Since the relative importance of the different sources depends on the type and extent of different habitats and on hydrological and topographic conditions, results from other regions/type of systems cannot be extrapolated to these estuaries. Here, δC is used to determine the importance of mangrove-derived carbon for Penaeus merguiensis (detritivore; shrimp), Ambassis vachellii (planktivore; fish), and Leiognathus equulus (benthivore; fish) from six small wet-dry tropical estuaries that differ in mangrove (C) cover and in type of terrestrial vegetation adjacent to the estuary. Bayesian mixing models confirmed that mangrove material was important to consumers in all estuaries. There was a gradient in this importance that agreed with the extent of mangrove forests in the estuaries, as C sources were the most important contributors to animals from the three estuaries with the greatest (>40 %) mangrove cover. There was also evidence of incorporation of C material for the three estuaries with lower (<30 %) mangrove cover. Since these latter estuaries had no adjacent terrestrial C forests, the detected C influence can only be of mangrove origin. This shows that mangroves are important contributors to these food webs, underlining the importance of mangroves in supporting estuarine nursery ground value and fisheries productivity. [ABSTRACT FROM AUTHOR]

The levels of mercury in tissues of Penaeus merguiensis from Musa estuary, northwest of the Persian Gulf, were investigated. This study assessed the relationship between mercury levels in hepatopancrea, gill, and muscle with sex, size, and season. The order of mercury concentrations in tissues of the shrimp P. merguiensis was as follows: hepatopancreas > gill > muscle. There was a positive correlation between mercury concentrations in shrimp species with sex and size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. Also, there was a positive correlation between mercury concentrations in shrimp species with its food source. Therefore, female species feed more on shrimp and plant and are contaminated with high levels of mercury. There was significant difference ( p < 0.05) in mercury levels between different seasons; higher mercury levels were found in July (summer season). [ABSTRACT FROM AUTHOR]

Postlarval and small juvenile Penaeus merguiensis were sampled fortnightly by beam trawls on the ebb tides over 4 years in the Matang mangroves on the west coast of peninsular Malaysia. Larger juveniles were sampled by bag nets on both the ebb and flood tides every fortnight over 5 years. Rainfall is consistently high throughout the year ( > 100 mm in each month) and the annual rainfall ranges from about 1,800 to 2,600 mm. Water temperatures ranged from 27°C to 36°C and salinity from 14‰ to 32‰ during this study. Fortnightly catches by beam trawls and bag nets were highly variable but showed a single broad period of postlarval and juvenile recruitment extending from December to May and an extended broad period of juvenile emigration from February to July. Beam trawl catches of postlarvae and juvenile prawns were consistently low between June and August. Higher catches of postlarvae and juveniles were recorded at two sites in close proximity to small adjoining creeks than one with no adjacent creek. Catches of juveniles in bag nets were higher during the day than the night and were correlated with the strength of the water flow. Environmental variables generally accounted for only a small proportion of the variation in catches, even for rainfall. The small proportion of variation explained by environmental variables is probably because of their relatively small seasonal variation in the Matang region. The lack of environmental influence on the catches of P. merguiensis implies that managing the mangrove nursery habitats and fishing pressure may be the main considerations for sustaining their stocks in the Matang region. [ABSTRACT FROM AUTHOR]

This study is focussed on evaluation of temperature effect during frozen storage on movement of trace elements in different tissues (exoskeleton, carapace and abdominal muscle) of two commercially important shrimp species (Penaeus merguiensis and Metapenaues affinis). Moreover relationships between total length and sex of specimens with concentration of trace elements in selected tissues were assessed. Concentrations of Cd, Cr, Cu, Fe, Mn, Ni and Zn in samples were determined by ICP-AES. Only in the case of Ni and Zn sex related differences could be observed. With the exception of Cu, the trace metals distributed significantly different between the tissues. The only significant differences between species were found in bioaccumulation of Mn. Size dependent relationship was observed only for Ni. Associations between Mn and Fe were positively and highly significant in all the cases. The levels of all the metals in muscle of the shrimps from the studied region were comparable to other world areas. Mean Cu and Zn levels in edible parts of M. affinis stored at –10 °C exceeded some existing guidelines, while the concentrations at –30 °C were somewhat lower than them. [ABSTRACT FROM AUTHOR]

Discusses the use of a dual stable carbon and nitrogen ratio approach to analyze the major primary food sources, the sediments and several species of penaeid prawns of a mangrove swamp in Perak, Malaysia. Analyses of muscle tissue and gut contents of the dominant species, Penaeus merguiensis; Carbon and nitrogen isotope ratios for samples collected inside and outside the Matang mangrove swamp; Contribution of mangrove detritus to prawn nutrition.

Provides information on a study which examined the impact of the cyanobacterium Trichodesmium spp. blooms on the penaeid prawn larvae. Development of the larvae of the prawn Penaeus merguiensis; Details on the usage of electron microscopy; Methodology used to conduct the study; Results of the study.

The article presents a study which examines the toxicological effect of dissolved copper on the banana prawn Penaeus merguiensis and the leader prawn Penaeus monodon. The study uses anodic stripping voltammetry (ASV), diluted nitric acid and inductively coupled plasma atomic emission spectrometry (ICPAES) to analyze copper concentration on the two species. Results show that dissolved copper has acute toxic effect on P. merguiensis and P. monodon.

The article focuses on a study which measures the toxicity pattern of cadmium and nickel accumulation in juvenile banana prawns (Penaeus merguiensis de Man). The study used the juvenile banana prawns from Three Mile Creek, near Townsville, Australia and conducted the tests in high density polyethylene tanks having 50 liters of seawater. The results found that cadmium has the most concentrated by the hepatopancreas and least concentrated by muscle over the 30-day exposure period.

The article presents a study which examines the concentration of heavy metals in the banana prawn Penaeus merguiensis and leader prawn Penaeus monodon in the Townsville Region of Australia. The study used 48 and 46 samples of banana prawns and atomic absorption spectrophotometry to examine the presence of copper, zinc, silver, manganese, cadmium, iron, nickel, lead and cobalt. Results show that the heavy metals' concentration in prawns from three locations were relatively clean and unpolluted.

Postlarval and juvenile Penaeus merguiensis de Man from the Embley River estuary on the north-eastern Gulf of Carpentaria were sampled every 2 wk from September 1986 until August 1989, using a small beam trawl. Settlement of planktonic postlarvae peaked during the pre-wet season (October to December), and declined through the wet season (January to March). Using length-frequency analysis between 12 and 14 cohorts of juvenile prawns were identified each year. Length-frequency analysis and modal progression were used to derive growth rates during the estuarine phase of the life cycle. Growth rates, which could be described by a linear model, ranged from 0.63 to 1.65 mm CL (carapace length) wk. Growth rates were positively influenced by water temperature and negatively influenced by prawn density. Salinity had no effect on growth rates. Prawns spent between 6 and 20 wk in the Embley River before emigrating offshore from the estuary. Weekly instantaneous rates of natural mortality (M) ranged from 0.23 to 0.94, and in general were lowest during the dry season (July to September) and highest during the pre-wet and wet seasons. Only temperature significantly influenced mortality rates, with mortality rates increasing with temperature. By projecting juvenile growth rates forward through time, we established which cohorts contributed to the offshore fishery each year. In 1987 and 1988 the April fishery consisted of prawns which had settled in the river before the end of January each year. Slow growth rates during the pre-wet season of 1988 meant that only cohorts that were settled before early December 1988 contributed to the fishery in April 1989. Whether a cohort contributes to the fishery depends on the settlement date, water temperature and prawn density. [ABSTRACT FROM AUTHOR]

Specimens of Penaeus merguiensis de Man were captured between February and May 1981 from intertidal creeks and beaches of Cleveland Bay, Townsville, Australia, using a 15 m seine net. The statocyst of P. merguiensis resembles that of other macrurans in that it is a dorsal invagination of the basal antennular segment lined with groups of sensory hairs. The statolith is composed of sand grains implanted by the prawn from the substratum which must be done after every moult. Implantation begins within 90 min of ecdysis and has 3 phases: sifting; digging and finally eye withdrawal which pushes the sand grains into the statocyst chamber. [ABSTRACT FROM AUTHOR]