कर्नाटक के नदिमुखों में पिंजरा मछली पालन

Estuarine Cage farming in Karnatak

Food and feeding habits of the narrow barred Spanish mackerel Scomberomorus commerson (Lacepede, 1800) off Karnataka, south-west coast of India

Scomberomorus commerson were collected on weekly basis during January 2012 to December 2014 at Mangalore Fishing Harbour. Stomach of 214 narrow barred Spanish mackerel measuring from 48 to 105 cm fork length (FL) for males and 45.5 to 115 cm FL for females were analysed to study their feeding habits. Fish with empty stomach were prevalent in almost all the months. Prey mainly comprised of fishes and crustaceans, with the fish component forming 99.9%. The index of relative importance (IRI) showed that the dominant prey were semi-digested fish remains (44.6%) of Sardinella longiceps (30.1%), Decapterus sp. (18.7%), whitebaits (2.5%), Rastrelliger kanagurta (1.5%) and Epinephelus spp. (1.1%), while Saurida sp. (0.7%), Megalaspis cordyla (0.5%), Scombroides sp. (0.2%) and shrimps (0.1%) were found occasionally in the gut. Index of stomach fullness (SFI) was 0.11 in August and 0.65 in January. Generally, SFI was higher during September to January and lower during February to August. The empty stomach ratio (ESR) ranged from 33.3% (August) to 92.3% (April)

Characteristics of crushed and alternative fine aggregates based on flow, shear and impact behaviour

18-28Crushed sand has been found to be an excellent replacement for river sand as the latter is not readily available. As a part of sustainable construction methods and practices, industrial by- products such as copper slag, cinder etc., can be used as alternative sands. In this work, an attempt has been made to study the performance of crushed stone sand for its flow properties based on large sample analysis.For this, 30 samples of crushed sand were procured from different sources. In addition, few alternative sands were also considered for the analysis which included copper slag, Ennore sand and two types of cinders. The parameters tested are flow time based on New Zeeland flow cone, loose bulk density, uncompacted voids and specific gravity. In order to enhance the performance of the poor crushed sand, different samples of crushed sands were blended which results in acceptable flow characteristics. Similar exercise was done for alternative sands by considering double or triple blending which finally resulted in good flow properties for possible use in concrete. In addition, few samples were also tested and evaluated for their shear and impact behaviour. Conclusions are drawn based on the results obtained

Estimation of Population Mean in the Presence of Non-Response and Measurement Error

Under classical survey sampling theory the errors mainly studied in the estimation are sampling errors. However, often non-sampling errors are more influential to the properties of the estimator than sampling errors. This is recognized by practitioners, researchers and many great works of literature regarding non-sampling errors have been published during last two decades, especially regarding non-response error which is one of the cornerstones of the non-sampling errors. The literature handles one kind of non-sampling error at a time, although in real surveys more than one non-sampling error is usually present.In this paper, two kinds of non-sampling errors are considered at the estimation stage: non-response and measurement error. An exponential ratio type estimator has been developed to estimate the population mean of the response variable in the presence of non-response and measurement errors. Theoretically and empirically, it has been shown that the proposed estimator is more efficient than usual unbiased estimator and other existing estimators.En la teoría de muestreo de la encuesta clásica los errores estudiados principalmente en la estimación son el muestreo errores. Sin embargo, a menudo los errores ajenos al muestreo son más influyentes que las propiedades del estimador de errores de muestreo. Esto es reconocido por los profesionales, los investigadores y muchos grandes obras de la literatura en relación con los errores ajenos al muestreo se ha publicado en los últimos dos decenios, especialmente en relación con el error de falta de respuesta, que es una de las piedras angulares de los errores ajenos al muestreo. La literatura se ocupa de un tipo de error no muestral a la vez, aunque en las encuestas reales más de un error no muestral suele estar presente. En este trabajo, dos tipos de errores ajenos al muestreo son considerados en la etapa de la estimación: la falta de respuesta y el error de medición. Un tipo exponencial estimador de razón ha sido desarrollado para estimar la media poblacional de la variable de respuesta en presencia de errores de falta de respuesta y de medición. Teóricamente y empíricamente, se ha mostrado que el estimador propuesto es más eficiente que estimador insesgado habitual y otros estimadores existentes

Alepes djedaba (Forsskal, 1775) - a promising carangid species for capture based aquaculture

Carangids are highly esteemed food fishes and have been evaluated as potential aquaculture species in different countries. Carangid fishes viz., Seriola quinqueradiata, Caranx mate and Trachinotus spp. are commercially cultured in Japan, Hawaii and USA respectively. Captive breeding and seed production of the silver pompano, Trachinotus blochii as well as the successful demonstration of farming of the hatchery produced pompano seed in earthern ponds is one of the breakthrough achievements of the Central Marine Fisheries Research Institute in India

Emerging commercial importance for Diamondback squid in Kerala and Karnataka

The incidental catches of Diamondback squid, Thysanoteuthis rhombus (Fig.1) has been reported from the Indian EEZ earlier. This monotypic oceanic species belonging to the Family Thysanoteuthidae, is found in tropical and subtropical seas of the world. A large squid species capable of attaining dorsal mantle length (DML) up to 100 cm and weighing about 24 kg, they are listed as Least Concer

Customized indigenous finfish cages developed for fish farmers of coastal Karnataka

Customized indigenous finfish cages developed for fish farmers of coastal Karnatak

Seasonal abundance and composition of finfish and shellfish seeds in mangroves of Gangolli estuary, off south-west coast of India

The composition and seasonal abundance of the fin and shellfish seeds in mangrove areas of Gangoli estuary were studied for one year from January to December, 2013. Monthly day time sampling was conducted with a rectangular dragnet of 75 m2 length having 5 mm mesh size. The mean monthly density was highest in January (Avg. of 12,996/haul) and lowest during May (Avg. of 859/haul). Thirty species of fish, four species of shrimps and two species of crabs belonging to 26 families were recorded during the study. Ambasis sp., Feneropenaeus indicus, Etroplus suratensis,Leognathus sp., Liza sp., Stolephorus vaganensis, Hemiramphus sp., Terapon sp. and Gerres sp. were the most abundant species/taxa. A total of 10 commercially important species comprising F. indicus, Etroplus suratensis, Liza sp., Gerres sp.,Siganus sp., Lutjanus russei, Macrobrachium rosenbergii, Lutjanus argentimaculatus, Sillago sp. and Penaeus monodon constituted 8.5% (April, 2013) to 93.7% (October, 2013) with an average of 37.2% of the total fish and shellfish seeds. Higher Species diversity (H') and Species richness (D) was recorded during January. The result of the present investigation gives an insight of the abundance and seasonality of commercially important fish and shellfish seeds, which may facilitate the brackishwater fish farmers to exploit the seeds more pragmatically for their culture practice

Environmental influence on the secondary productivity and fish abundance in coastal fishing grounds off Mangalore, south-eastern Arabian Sea

Environmental parameters influence the productivity and abundance of fish in marine ecosystems. In this study, we attempted to analyse the relationship between environmental parameters and abundance of fish in trawling grounds in south-eastern Arabian Sea along the coast of Karnataka. Among the 85 species of finfishes and shellfishes caught in the trawling grounds, 41 finfish species, 24 crustaceans, 18 molluscs and two echinoderms were recorded. Seasonal differences were seen in biomass with the highest biomass during the post-monsoon period (October-January). Water temperature and nutrients were the key contributing factors of seasonal differences in the biotic communities studied. Season specific diagnostic species were identified using SIMPER analysis. Squilla which formed the major prey item of most of the demersal fishes dominated (>40%) coastal grounds throughout all seasons. This could be considered as a fishery indicator of the region. The dominance and abundance of copepods was found to be influenced by sea surface temperature (SST) and nutrients. The results of the study have implications on the fishery, knowledge on environmental factors influencing the abundance and importance of non-commercial species in sustaining the fishery in the region

Combined effect of steel fibres and steel rebars on impact resistance of high performance concrete

The investigation on the impact properties of normal concrete (NC)and reinforced concrete (RC) specimens, steel fibre reinforced concrete (SFRC) specimens and RC+SFRC specimens with different steel fibres dosages were carried out with the drop-weight impact test recommended by ACI Committee 544. The results indicate that the number of blows to final failure greatly increased by addition of steel fibres. Moreover, the combination of steel fibres and steel rebars demonstrates a significant positive composite effect on the impact resistance, which results on the improvement in impact toughness of concrete specimens. In view of the variation of impact test results, the two-parameter Weibull distribution was adopted to analyze the experimental data. It is proved that the probabilistic distribution of the blows to first crack and to final failure of six types of samples are approximately two-parameter Weibull distribution.Funded by the National Natural Science Foundation of China (NSFC) (Grant No.50578026)Financial support provided by the Research Center of Mathematics of the University of Minho through the FCT Pluriannual Funding Progra