Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes domina...Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes dominated over local fishes in the fishery, which was over 96% at Etawah. The calculated Invasion Coefficient Index (Ixi) of alien invasive fishes was in the range of 0.12 to 0.31 indicating a major loss to the local fish diversity. The calculated Pearson’s correlation coefficient was found to have positive correlation of 0.757 and 0.710 for common carp and tilapia respectively with locally captured Indian major carps (IMC). The results of this study highlighted how unintentional spread of alien invasive fishes due to rapid aquaculture diversification and intensification has invaded into the Yamuna River causing severe loss to the local fishery. The invasion of alien fishes has been mapped for the Yamuna River at different locations using GIS tools. The results of this study invite attention on the management and sustainability of the local fishery and ecosystem health of the river.展开更多
Aeromonas hydrophila is an important bacterial pathogen which causes the hemorrhagic septicemia in fishes, amphibians and humans. Genetic relationships of diverse isolates of A. hydrophila were recovered from fish and...Aeromonas hydrophila is an important bacterial pathogen which causes the hemorrhagic septicemia in fishes, amphibians and humans. Genetic relationships of diverse isolates of A. hydrophila were recovered from fish and water sources. These isolates were investigated by flanked region of 16S and 23S Ribosomal DNA (rDNA) internal transcribed spacer (ITS). Here we analyzed polymorphism of PCR-amplified 16S-23S rDNA ITS and their revealed band pattern consisting of one to four DNA fragments. The fragment size ranged from 500 to 1000 bp. The DNA band patterns revealed a considerable genetic diversity in interaspecies. The 750 bp size of band was common in all isolates of A. hydrophila except one Isolates AH21. The tRNA-Glu sequences were identified from 750 bp size of ITS region that could be used as strain level potential genotypic markers.展开更多
Giant river catfish (Mystus seenghala) from the Beas river were compared with a population in the Sutlej river of theIndus river system using 28 morphometric characters. Discriminant analyses and a univariate ANOVA we...Giant river catfish (Mystus seenghala) from the Beas river were compared with a population in the Sutlej river of theIndus river system using 28 morphometric characters. Discriminant analyses and a univariate ANOVA were used toexplore these data. Allometric transformation of each measurement was done to eliminate correlations with size. Thestepwise discriminant analysis retained nine variables that significantly discriminated the Beas samples from theSutlej samples. Using these variables, 91.2% (original) and 89.0% (cross validated) of fish were classified into theircorrect samples. Misclassification was higher for the Sutlej samples (12.5%) than for the Beas samples (6.3%). Theresults of the discriminant analyses showed that variability in the Beas samples was more homogeneous andprovided a more characteristic picture of the group than the Sutlej samples. The univariate ANOVA revealed significantdifferences between the means of the two populations for 12 of the 28 transformed morphometric measurements.展开更多
Objective:To determine the physiological and ecological responses of marine ornamental fishes to the change of water temperature with its potential effects on the growth,survival and feeding in clown fish.Methods:Thre...Objective:To determine the physiological and ecological responses of marine ornamental fishes to the change of water temperature with its potential effects on the growth,survival and feeding in clown fish.Methods:Three different sea anemone fish(Premnas biaculeatus,Amphiprion clarkii,Amphiprion akallopisos)were reared in confinement at water temperatures of 26,28,30,32,and 34℃using thermostat and they were maintained up to the marketable size,and growth,survival and feeding were evaluated during the experimental period.Results:The results illustrated that water temperature influenced the physiological performance of juveniles of three different sea anemone fish significantly.The growth and survival rates of juveniles of three different clown fish significantly increased with the increase of water temperature from 26℃to 34℃(P<0.05).Water temperature also influenced the feeding of three different clown fish significantly with feed conversion ratio increased from(0.071±0.020),(0.075±0.030)and(0.079±0.028)to(0.057±0.040),(0.047±0.030)and(0.045±0.028)for Premnas biaculeatus,Amphiprion clarkii and Amphiprion akallopisos respectively with increase of water temperature from 26℃to 34℃(P<0.05).Specific growth rates(P<0.05)increased significantly with increase of water temperature and positively correlated with the feed conversion ratio,indicating that growth rates are significantly increased with increase of temperature.Conclusions:This study deliberately reveals that the physiological response of juveniles of clown fish as the change of water temperature and substantiated that water temperature influenced juvenile growth,survival and feeding significantly.This study also put forward that the reduced growth,survival and feeding of juveniles at lower temperature which have ecological impacts on clown fish juveniles in settlement and population replacement in the wild.展开更多
Objective:To study the lymphocystis disease virus(LCDV)in two species of marine ormamental fishes through histopathological investigation along with control for differentiating the tissue damage.Methods:Six naturally ...Objective:To study the lymphocystis disease virus(LCDV)in two species of marine ormamental fishes through histopathological investigation along with control for differentiating the tissue damage.Methods:Six naturally infected fishes were collected.They were anaesthetized and subsequently killed by organ dissection.The infected fish organs were aseptically cut off and stored with 10%formalin solution for histological study.Samples were examined for gross pathology including location,distribution,shape,size,colour,consistency and special features of typical external lesions by standard method.Results:The diameter of the tumor nodules ranged from 1 to 2 mm(Amphiprion ocellaris)and 2.5 to 3.5 mm(Amphiprion percula).Light microscopic observation showed over growth of tumor like nodules on the skin or scales and ventral side as well.Numerous hy pertrophied cells with basophilic intracytoplasmic inclusion bodies were in the connective tissues of dermis and between scales on two species.The nucleus of lymphocystis cell were enlarged,irregular and containing basophilic marginated chromatin.Thus,the similarities among cellular patterns of different fish LCDV isolates from different hosts indicated that these profiles do not depend on the host species.Conclusions:In conclusion,this current study of histopathological statement of LCDV may be adequate for a presumptive diagnosis of lymphocystis disease from both marine as well as fresh water fish species.The findings of asymptomatic carriers by histology using infected skin and fin sampling,which does not imply animal killing,could be important tool to epizootics caused by LCDV.This study may be very useful for further molecular studies.展开更多
文摘Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes dominated over local fishes in the fishery, which was over 96% at Etawah. The calculated Invasion Coefficient Index (Ixi) of alien invasive fishes was in the range of 0.12 to 0.31 indicating a major loss to the local fish diversity. The calculated Pearson’s correlation coefficient was found to have positive correlation of 0.757 and 0.710 for common carp and tilapia respectively with locally captured Indian major carps (IMC). The results of this study highlighted how unintentional spread of alien invasive fishes due to rapid aquaculture diversification and intensification has invaded into the Yamuna River causing severe loss to the local fishery. The invasion of alien fishes has been mapped for the Yamuna River at different locations using GIS tools. The results of this study invite attention on the management and sustainability of the local fishery and ecosystem health of the river.
文摘Aeromonas hydrophila is an important bacterial pathogen which causes the hemorrhagic septicemia in fishes, amphibians and humans. Genetic relationships of diverse isolates of A. hydrophila were recovered from fish and water sources. These isolates were investigated by flanked region of 16S and 23S Ribosomal DNA (rDNA) internal transcribed spacer (ITS). Here we analyzed polymorphism of PCR-amplified 16S-23S rDNA ITS and their revealed band pattern consisting of one to four DNA fragments. The fragment size ranged from 500 to 1000 bp. The DNA band patterns revealed a considerable genetic diversity in interaspecies. The 750 bp size of band was common in all isolates of A. hydrophila except one Isolates AH21. The tRNA-Glu sequences were identified from 750 bp size of ITS region that could be used as strain level potential genotypic markers.
基金This research was funded by the grants from Project Implementation Unit National Agricultural Technology Project of Indian Council of AgriculturalResearch, NewDelhi .
文摘Giant river catfish (Mystus seenghala) from the Beas river were compared with a population in the Sutlej river of theIndus river system using 28 morphometric characters. Discriminant analyses and a univariate ANOVA were used toexplore these data. Allometric transformation of each measurement was done to eliminate correlations with size. Thestepwise discriminant analysis retained nine variables that significantly discriminated the Beas samples from theSutlej samples. Using these variables, 91.2% (original) and 89.0% (cross validated) of fish were classified into theircorrect samples. Misclassification was higher for the Sutlej samples (12.5%) than for the Beas samples (6.3%). Theresults of the discriminant analyses showed that variability in the Beas samples was more homogeneous andprovided a more characteristic picture of the group than the Sutlej samples. The univariate ANOVA revealed significantdifferences between the means of the two populations for 12 of the 28 transformed morphometric measurements.
基金Supported by the Director of the Centre and the authorities of Annamalai University for providing with facilities and Center for Marine Living Resource and Ecology(CMLRE-Office Memorandum No:G4/3366/2013),Ministry of Earth Sciences for financial assistant.
文摘Objective:To determine the physiological and ecological responses of marine ornamental fishes to the change of water temperature with its potential effects on the growth,survival and feeding in clown fish.Methods:Three different sea anemone fish(Premnas biaculeatus,Amphiprion clarkii,Amphiprion akallopisos)were reared in confinement at water temperatures of 26,28,30,32,and 34℃using thermostat and they were maintained up to the marketable size,and growth,survival and feeding were evaluated during the experimental period.Results:The results illustrated that water temperature influenced the physiological performance of juveniles of three different sea anemone fish significantly.The growth and survival rates of juveniles of three different clown fish significantly increased with the increase of water temperature from 26℃to 34℃(P<0.05).Water temperature also influenced the feeding of three different clown fish significantly with feed conversion ratio increased from(0.071±0.020),(0.075±0.030)and(0.079±0.028)to(0.057±0.040),(0.047±0.030)and(0.045±0.028)for Premnas biaculeatus,Amphiprion clarkii and Amphiprion akallopisos respectively with increase of water temperature from 26℃to 34℃(P<0.05).Specific growth rates(P<0.05)increased significantly with increase of water temperature and positively correlated with the feed conversion ratio,indicating that growth rates are significantly increased with increase of temperature.Conclusions:This study deliberately reveals that the physiological response of juveniles of clown fish as the change of water temperature and substantiated that water temperature influenced juvenile growth,survival and feeding significantly.This study also put forward that the reduced growth,survival and feeding of juveniles at lower temperature which have ecological impacts on clown fish juveniles in settlement and population replacement in the wild.
基金Supported by Center for Marine Living Resource and Ecology,Ministry of Earth Sciences(CMLRE-Office Memorandum No:G4/3366/2013).
文摘Objective:To study the lymphocystis disease virus(LCDV)in two species of marine ormamental fishes through histopathological investigation along with control for differentiating the tissue damage.Methods:Six naturally infected fishes were collected.They were anaesthetized and subsequently killed by organ dissection.The infected fish organs were aseptically cut off and stored with 10%formalin solution for histological study.Samples were examined for gross pathology including location,distribution,shape,size,colour,consistency and special features of typical external lesions by standard method.Results:The diameter of the tumor nodules ranged from 1 to 2 mm(Amphiprion ocellaris)and 2.5 to 3.5 mm(Amphiprion percula).Light microscopic observation showed over growth of tumor like nodules on the skin or scales and ventral side as well.Numerous hy pertrophied cells with basophilic intracytoplasmic inclusion bodies were in the connective tissues of dermis and between scales on two species.The nucleus of lymphocystis cell were enlarged,irregular and containing basophilic marginated chromatin.Thus,the similarities among cellular patterns of different fish LCDV isolates from different hosts indicated that these profiles do not depend on the host species.Conclusions:In conclusion,this current study of histopathological statement of LCDV may be adequate for a presumptive diagnosis of lymphocystis disease from both marine as well as fresh water fish species.The findings of asymptomatic carriers by histology using infected skin and fin sampling,which does not imply animal killing,could be important tool to epizootics caused by LCDV.This study may be very useful for further molecular studies.
