404 research outputs found

    Indian Efforts on the Inventorization of Marine Mammal Species for their Conservation and Management

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    The present study is the first attempt to use molecular tools for identification of marine mammals in India. The objective was to develop a database of genetic sequences for future marine mammal research in addition to confirming the species identity of cetaceans and dugongs using a molecular approach. Partial sequencing of mitochondrial DNA loci was carried out in accidentally caught/stranded specimens of Spinner dolphin (Stenella longirostris), Pantropical spotted dolphin/bridled dolphin (Stenella attenuata), Bottlenose dolphin (Tursiops aduncus), Long-beaked common dolphin (Delphinus capensis), Indopacific humpbacked dolphin (Sousa chinensis), RissoтАЩs dolphin (Grampus griseus), Finless porpoise (Neophocaena phocaenoides), Sperm whale (Physeter macrocephalus), Blue whale (Balaenoptera musculus), BrydeтАЩs whale (Balaenoptera edeni) and Dugong (Dugong dugon). Molecular identification of species was done by phylogenetic reconstruction of the sequences using portals GenBank and DNA Surveillance. Apart from ratifying their morphological identification, the analysis was able to distinguish specimens that otherwise, could not have been identified using conventional approaches. Phylogenetic analysis of the Sousa-Stenella-Tursiops-Delphinus group indicated more or less robust monophyly for all species in this complex, except Delphinus capensis. A sister-group relationship for Sperm whales and Baleen whales was evident, that would place the former closer to the latter than to any other group of toothed whales

    A note on cetacean distribution in the Indian EEZ and contiguous seas during 2003-07

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    Relatively little is known about the distribution of cetaceans in Indian seas due to lack of systematic surveys. For collecting data on species distribution, 35 opportunistic surveys were conducted onboard FORV Sagar Sampada between October 2003 and February 2007 in the Indian EEZ and contiguous seas. In 5,254 hours of sighting effort, a total of 473 cetacean records were made with 5,865 individuals. The occurrence of 10 species from three cetacean families was confirmed. The Indo-Pacific bottlenose dolphin was the most frequently sighted species, whereas the spinner dolphin was dominant in terms of abundance. Long-beaked common dolphins, Indo-Pacific hump-backed dolphin and sperm whales were also recorded at frequent intervals. Cetaceans were found to have a wide geographical distribution in the Indian EEZ and contiguous seas. High abundance and species richness were recorded in the Southeastern Arabian Sea and southern Sri Lankan waters. From the information collected during the present study, the platform of opportunity has proved to be a useful means for cetacean surve

    Automatic modulation classification for cognitive radios using cumulants based on fractional lower order statistics

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    Automatic modulation classification (AMC) finds various applications in cognitive radios. This paper presents a method for the automatic classification using cumulants derived using fractional lower order statistics. The performance of the classifier is presented in the form of probability of correct classification under noisy and fading conditions. Unlike many of the conventional methods, the proposed method does not require a priori knowledge of signal parameters. The proposed method is also more robust to different noises. Simulation results show that the proposed method can achieve better classification accuracy when compared to conventional cumulant based AMC method, in various impulsive noise conditions. 1

    Observations on incidental catch of cetaceans in three landing centres along the Indian coast

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    A short term survey to quantify the number of marine mammals incidentally caught, and interviews to gain perceptions of local fishers towards issues of by-catch, were conducted. A total of 44 cetaceans were recorded as incidental catches at Chennai, Kakinada and Mangalore fishing harbours during 80 days of observation. Six species of dolphins and one species of porpoise were recorded. The spinner dolphin Stenella longirostris was the most frequently caught (38.6%), followed by the finless porpoise Neophocaena phocaenoides (31.8%). Gillnets and purse seines operated from motorised boats accounted for the entire by-catch. It is estimated that 9000тАУ10,000 cetaceans are killed by gillnets every year along the Indian coast. The intricacies and possibilities of reducing cetacean kills by gillnets are discussed in the pape

    Mitochondrial DNA sequencing of cetaceans and dugong from the Indian seas for their conservation and management

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    Understanding taxonomy is fundamental to conservation efforts of bioresources. The units on which conservation is based are determined largely by species designation. Ambiguous identification of species may lead to erroneous conclusions, which may be more serious than lack of understanding of the population structure and status; for example, conclusions such as loss of genetic variability(e.g., by unwitting extinction of a species).In cetaceans (whales,dolphins andporpoises), morphological features are subtle and difficult to compare because of the rarity of specimens or widespread distributions.Identifying the geographical variants of recognized species of cetaceans is more cumbersome using the conventional approaches and in this context molecular genetics can provide significant contributions to taxonomic understanding of inter and intra-specific variations for conservation and management purposes. Similarly, in dugong,a critically endangered marine mammal, in order to devise adequate conservation andmanagement strategies for the species of concern, it is essential to study the population genetic characteristics of the species throughout the range of its distribution. DNA sequence analysis has become a powerful tool for conservation

    Stomach contents of cetaceans incidentally caught along Mangalore and Chennai coasts of India

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    Abstract The stomachs of 32 individuals of seven cetacean species incidentally caught in gill net and purseseine fisheries along Mangalore and Chennai coasts (India) between 2004 and 2006 were examined. The whole stomach (fore-gut, mid-gut and hind-gut) was examined in all cases. Prey remains (666 prey items comprising six species of teleosts, one crustacean and one squid species) were found in the stomachs of eight individuals (the remaining 24 stomachs were found to be empty). All cetaceans were found to feed mostly on teleosts with wide range of trophic levels. Based on an index that included frequency of occurrence, percentage by number and by weight, the oil sardine Sardinella longiceps was the main prey in the sample. Cetaceans appear to favour both pelagic as well as demersal prey, possibly indicating surface and benthic feeding habits

    Record of stranded whales along Karnataka coast

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    A whale was stranded in the beach of Guijerbettu, Udupi district, Karnataka on 21.12.2001 . The whale was found in live condition. Thelocal person tried to rescue it but was in vain and later it died. The whale was identified as Balaenopteramusculus (Blue whale). Few vertebrae have been collected and preserved in the museum of Mangalore Research Centre of CMFRI for future identification up to the species level. Another whale (genus : Balaenoptera) was stranded in Kota, Udupi district, Karnataka near the shore of Arama temple on 11.08.2004 in decayed condition

    Potential of Egg shell powder as replacement of Lime in soil stabilization

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    This paper presents a study on the properties of soil stabilized by using lime and egg shell powder. Tests were conducted to assess the potential of egg shell powder in replacing lime, which can make the overall stabilization process economical and eco-friendly. Results obtained show that all the treated mixes gave much better strength than untreated soil. Egg shell powder was introduced in quantities of 0.5%, 1%, 1.5% and 2% of the weight of soil. Tests were conducted replacing up to 50% of the lime used for stabilization. It was observed that 25% replacement of lime by egg shell powder gave better strength properties and can be adopted for practical purposes

    Dinoflagellaten als oorzaak van verlammende mosselvergiftiging

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    We have undertaken a high resolution palaeoclimate reconstruction on radiocarbon dated palaeolake sediments from the Spiti valley, NW Himalaya. This site lies in the climatically sensitive winter westerlies and Indian Summer Monsoon (ISM) transitional regime and provides an opportunity to reconstruct the precipitation seasonality, and extreme precipitation events that are characterised by intensified erosion. The lake sediments reveal distinct lithofacies that provide evidence of changes in depositional environment and climate during early to mid Holocene (8.7тАУ6.1 cal ka BP). We have identified three stages during the period of lake's existence: the Stage I (8.7тАУ7.6 cal ka BP) is marked by lake establishment; Stage II (тИ╝7.6тАУ6.8 cal ka BP) by sustained cooler periods and weakened summer monsoon, and Stage III (тИ╝6.8тАУ6.1 cal ka BP) by a shift from colder to warmer climate with stronger ISM. We have identified several short term cooler periods at ca. 8.7, 8.5, 8.3 and 7.2тАУ6.9 cal ka BP. Based on an overview of regional climate records we show that there is an abrupt switch in precipitation seasonality ca. 6.8 cal ka BP that is followed by the onset of the intensified monsoon in the NW Himalaya
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