12,917 research outputs found

    Evaluation of a simple tagging method to monitor the growth of endangered species of seahorse

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    Identification of an individual seahorse is important for captive breeding and conservation studies. A simple and cost-effective tagging method was devised to suit the rigid body structure and small fins of Hippocampus kuda. The first generation sexually matured individuals (452 numbers) were tagged using plastic strips tied around the neck. No significant differences (P > 0.05) in growth between the tagged and untagged groups were noted. All the tags persisted for one year without any perceptible changes in sexual and social behaviour

    Breeding, rearing and sea-ranching of chanks

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    The heavy demand, concomitant with specific expldltattoti as welt as bottom trawling led to habitat destruction and depletion oj sacred chank Xancus pyrum. Experiments conducted to study the natural growth and breeding aspects indicate that during March and November, the chanks release egg capsules containing fertilised eggs. The deuelopment is direct and the babies hatch out after 32 to 35 days of incubation at an ambient temperature 30.7┬░C. During their early stages, they feed on oligochaete and polychaete worms. From an initial 9.09 mm, they grow to 62.23mm In an year, while the MSD increased to 27.40 mm. They weighedfrom 0,14 to 32.36 g during one year. Chanks are non-migratory and their natural growth in sea indicated an average MSD growth ofS.Omm/yearforXancus pyrum var. acuta

    Species-specific proteins in closely-related seahorses

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    Non-denatured polyacrylanlide gel shows the respective species-specific characteristics on the muscle protein of' Hippocampus kuda and N. trirnacrtiahs. Two proteins; of molecular weight 66.8 and 39.8 kDa were found exclusively in 11. kuda. These constituted about 69.8 and 16.2% respectively of its protein. In M. trintucuirtus, two other specific proteins with molecular weight of 674.3 and 50.5 kDa were recorded, which constituted 46.0 and 7.5% respectively of its protein. These species-specific proteins are important for species identification, which paves avenues for further characterization and upgrading of the available information on seahorse taxonomy

    Faster Separators for Shallow Minor-Free Graphs via Dynamic Approximate Distance Oracles

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    Plotkin, Rao, and Smith (SODA'97) showed that any graph with mm edges and nn vertices that excludes KhK_h as a depth O(тДУlogтБбn)O(\ell\log n)-minor has a separator of size O(n/тДУ+тДУh2logтБбn)O(n/\ell + \ell h^2\log n) and that such a separator can be found in O(mn/тДУ)O(mn/\ell) time. A time bound of O(m+n2+╧╡/тДУ)O(m + n^{2+\epsilon}/\ell) for any constant ╧╡>0\epsilon > 0 was later given (W., FOCS'11) which is an improvement for non-sparse graphs. We give three new algorithms. The first has the same separator size and running time O(\mbox{poly}(h)\ell m^{1+\epsilon}). This is a significant improvement for small hh and тДУ\ell. If тДУ=╬й(n╧╡тА▓)\ell = \Omega(n^{\epsilon'}) for an arbitrarily small chosen constant ╧╡тА▓>0\epsilon' > 0, we get a time bound of O(\mbox{poly}(h)\ell n^{1+\epsilon}). The second algorithm achieves the same separator size (with a slightly larger polynomial dependency on hh) and running time O(\mbox{poly}(h)(\sqrt\ell n^{1+\epsilon} + n^{2+\epsilon}/\ell^{3/2})) when тДУ=╬й(n╧╡тА▓)\ell = \Omega(n^{\epsilon'}). Our third algorithm has running time O(\mbox{poly}(h)\sqrt\ell n^{1+\epsilon}) when тДУ=╬й(n╧╡тА▓)\ell = \Omega(n^{\epsilon'}). It finds a separator of size O(n/\ell) + \tilde O(\mbox{poly}(h)\ell\sqrt n) which is no worse than previous bounds when hh is fixed and тДУ=O~(n1/4)\ell = \tilde O(n^{1/4}). A main tool in obtaining our results is a novel application of a decremental approximate distance oracle of Roditty and Zwick.Comment: 16 pages. Full version of the paper that appeared at ICALP'14. Minor fixes regarding the time bounds such that these bounds hold also for non-sparse graph

    Onset of sexual maturity in captivereared endangered Indian seahorse, Hippocampus kuda

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    The endangered Indian seahorse, Hippocampus kuda successfully reared in captive conditions for more than two years, repeatedly spawned and produced F2 generations. In F1 males, brood pouch started developingfrom 55 to 60 days of birth. The courtship behaviour was noted 30 days subsequently and males started receiving eggs in their pouch when their body length attained 101.0 ┬▒ 2.0 mm. Females started transferring eggs into the male brood pouch when their body length reached 110.0 ┬▒ 2.0 mm. The sexual maturity of male was earlier than that of female. Compared to the age (in days), the size was inferred as a reliable factor to predict the onset of maturity in this species

    Captive Breeding and Nursery Rearing of the Indian Seahorse, Hippocampus kuda (Teleostei: Syngnathidae)

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    Breeding of laboratory-reared 21 pairs of broodstock Hippocampus kuda (Bleeker 1852) and rearing of their young ones indicated that 262.00 ┬▒ 59.00 offsprings were released during each spawning. A newly born seahorse was (mean ┬▒ SE) 7.83 ┬▒ 0.11 mm in length with a weight of 1.17 ┬▒ 0.009 mg. It could attain a mean length of 31.14 ┬▒ 0.66 mm with a mean weight of 16.13 ┬▒ 0.60 mg in 30 days when fed ad libitum with Artemia nauplii. The mean survival per brood cycle was enhanced to 65.22 ┬▒ 1.87% from almost less than 1.0% by improving the rearing conditions

    Antibacterial activity of aqueous extract from selected macroalgae of southwest coast of India

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    Aqueous extract of seven species of marine macroalgae were screened for their antimicrobial potency against ten pathogenic bacterial strains. Ulva fasciata, Gracilaria corticata, Sargassum wightii and Padina tetrastromatica showed significantly higher activity against 70% of the tested bacterial isolates. The maximum zone of inhibition was noted for the red alga G.corticata against Proteus mirabilis (17mm) and brown alga P. tetrastromatica against the pathogens Staphylococcus aureus and Vibrio harveyi (15mm). The general trend of inhibitory activity was higher towards Gram negative bacteria

    Polymicrobial skin lesions in the red spot emperor, Lethrinus lentjan (Lacepede 1802) during mass incursion towards shore along Kanyakumari coast, south India

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    Mass incursion of fishes with polymicrobial skin lesions, fin erosions and scale loss was recorded in the red spot emperor Lethrinus lentjan (Lacepede 1802) along the Kanyakumari coast, south India during August 2009. An estimated 2.5 t of fish, mostly the red spot emperors were found to migrate in live condition to the shore areas in a stressful state. Microbiological analyses of tissue from sampled fishes revealed three distinct types of bacterial colonies forming 5.2 x 105 CFU g-1 of the infected tissues. The predominant bacterial colonies were characterized as Aeromonas sp. (70.0%) followed by Flavobacterium sp. (20%) and Vibrio sp. (10%). The Aeromonas isolate was highly susceptible to norfloxacin while the Flavobacterium and Vibrio isolates were susceptible to chloramphenicol. The Aeromonas and Vibrio isolates exhibited protease and amylase enzyme activities in vitro, suggesting their possible role in the progression of skin lesions and scale loss. The possibilities of ambient unknown stressors weakening the fish and subsequent infections by these bacterial isolates are discussed
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