RESUMEN

This investigation presents the food and feeding activity of and endangered riverine catfish Rita rita, during February 2017-January 2018. A total of 225 fish individuals was analyzed for stomach contents by characterizing the dominant food items and morphometric features. The results divulged ten major food items consumed, preferably fish scales and eggs, teleost fishes, copepods, cladocerans, rotifers, and mollusks. Total length and body weight of fish varied between 9-34 cm (20.53 ± 6.90 cm) and 10-400 g (9125.94 ± 102.07 g), respectively. The index of relative importance (IRI%) showed the importance of rotifers over the other food items. Morisita's index of diet overlap indicated seasonal variations in catfish diets with summer and monsoon displaying the least overlap, while maximum overlap during monsoon and winter seasons. The non-metric multidimensional scaling (nMDS) indicated the close association between the food items available during summer and winter seasons with a significant difference among the seasons (ANOSIM, R = 0.638, P = 0.013). Levins niche breadth index arranged in the order of 0.88>0.81>0.78>0.63>0.43 for the size classes of V, IV, III, II and I, respectively. The PCA explained 95.39% of the total variance among the food items and fish size groups. Small-sized fish individuals displayed a greater correlation with food items suitable for their mouth size. In conclusion, the variety and frequency of food items recorded indicated considerable feeding plasticity and opportunistic feeding behavior with a shift from carnivorous to omnivorous feeding nature. This study could render useful information on the food and feeding habits of R. rita and provide background for preparing its diet for future aquaculture practices.(AU)

Esta investigação apresenta a alimentação e a atividade alimentar de bagres ribeirinhos Rita rita ameaçados de extinção, no período de fevereiro de 2017 a janeiro de 2018. Um total de 225 peixes foi analisado quanto ao conteúdo do estômago, caracterizando os itens alimentares dominantes e as características morfométricas. Os resultados apresentaram dez principais itens alimentares consumidos, preferencialmente escamas e ovos de peixes, teleósteos, copépodes, cladóceros, rotíferos e moluscos. O comprimento total e o peso corporal dos peixes variaram entre 9-34 cm (20,53 ± 6,90 cm) e 10-400 g (9125,94 ± 102,07 g), respectivamente. O índice de importância relativa (IRI%) mostrou a importância dos rotíferos sobre os demais itens alimentares. O índice de sobreposição de dieta de Morisita indicou variações sazonais nas dietas de bagres no verão e nas monções, exibindo a menor sobreposição, enquanto a sobreposição máxima ocorreu durante as estações das monções e do inverno. A escala multidimensional não métrica (nMDS) indicou a estreita associação entre os itens alimentares disponíveis durante o verão e o inverno, com uma diferença significativa entre as estações (ANOSIM, R = 0,638, P = 0,013). O índice de amplitude de nicho de Levin foi organizado na ordem de 0,88 > 0,81 > 0,78 > 0,63 > 0,43 para as classes de tamanho de V, IV, III, II e I, respectivamente. O PCA explicou 95,39% da variação total entre os itens alimentares e os grupos de tamanho de peixes. Peixes de pequeno porte apresentaram maior correlação com itens alimentares adequados ao tamanho da boca. Em conclusão, a variedade e a frequência dos itens alimentares registrados indicaram plasticidade alimentar considerável e comportamento alimentar oportunista, com uma mudança da natureza carnívora para onívora. Este estudo pode fornecer informações úteis sobre os hábitos alimentares e de alimentação de R. rita e apresentar subsídios para a preparação de sua dieta em futuras práticas de aquicultura.(AU)

Asunto(s)

RESUMEN

This investigation presents the food and feeding activity of and endangered riverine catfish Rita rita, during February 2017-January 2018. A total of 225 fish individuals was analyzed for stomach contents by characterizing the dominant food items and morphometric features. The results divulged ten major food items consumed, preferably fish scales and eggs, teleost fishes, copepods, cladocerans, rotifers, and mollusks. Total length and body weight of fish varied between 9-34 cm (20.53 ± 6.90 cm) and 10-400 g (9125.94 ± 102.07 g), respectively. The index of relative importance (IRI%) showed the importance of rotifers over the other food items. Morisita's index of diet overlap indicated seasonal variations in catfish diets with summer and monsoon displaying the least overlap, while maximum overlap during monsoon and winter seasons. The non-metric multidimensional scaling (nMDS) indicated the close association between the food items available during summer and winter seasons with a significant difference among the seasons (ANOSIM, R = 0.638, P = 0.013). Levin's niche breadth index arranged in the order of 0.88>0.81>0.78>0.63>0.43 for the size classes of V, IV, III, II and I, respectively. The PCA explained 95.39% of the total variance among the food items and fish size groups. Small-sized fish individuals displayed a greater correlation with food items suitable for their mouth size. In conclusion, the variety and frequency of food items recorded indicated considerable feeding plasticity and opportunistic feeding behavior with a shift from carnivorous to omnivorous feeding nature. This study could render useful information on the food and feeding habits of R. rita and provide background for preparing its diet for future aquaculture practices.

Esta investigação apresenta a alimentação e a atividade alimentar de bagres ribeirinhos Rita rita ameaçados de extinção, no período de fevereiro de 2017 a janeiro de 2018. Um total de 225 peixes foi analisado quanto ao conteúdo do estômago, caracterizando os itens alimentares dominantes e as características morfométricas. Os resultados apresentaram dez principais itens alimentares consumidos, preferencialmente escamas e ovos de peixes, teleósteos, copépodes, cladóceros, rotíferos e moluscos. O comprimento total e o peso corporal dos peixes variaram entre 9-34 cm (20,53 ± 6,90 cm) e 10-400 g (9125,94 ± 102,07 g), respectivamente. O índice de importância relativa (IRI%) mostrou a importância dos rotíferos sobre os demais itens alimentares. O índice de sobreposição de dieta de Morisita indicou variações sazonais nas dietas de bagres no verão e nas monções, exibindo a menor sobreposição, enquanto a sobreposição máxima ocorreu durante as estações das monções e do inverno. A escala multidimensional não métrica (nMDS) indicou a estreita associação entre os itens alimentares disponíveis durante o verão e o inverno, com uma diferença significativa entre as estações (ANOSIM, R = 0,638, P = 0,013). O índice de amplitude de nicho de Levin foi organizado na ordem de 0,88 > 0,81 > 0,78 > 0,63 > 0,43 para as classes de tamanho de V, IV, III, II e I, respectivamente. O PCA explicou 95,39% da variação total entre os itens alimentares e os grupos de tamanho de peixes. Peixes de pequeno porte apresentaram maior correlação com itens alimentares adequados ao tamanho da boca. Em conclusão, a variedade e a frequência dos itens alimentares registrados indicaram plasticidade alimentar considerável e comportamento alimentar oportunista, com uma mudança da natureza carnívora para onívora. Este estudo pode fornecer informações úteis sobre os hábitos alimentares e de alimentação de R. rita e apresentar subsídios para a preparação de sua dieta em futuras práticas de aquicultura.

Asunto(s)

RESUMEN

This investigation presents the food and feeding activity of and endangered riverine catfish Rita rita, during February 2017-January 2018. A total of 225 fish individuals was analyzed for stomach contents by characterizing the dominant food items and morphometric features. The results divulged ten major food items consumed, preferably fish scales and eggs, teleost fishes, copepods, cladocerans, rotifers, and mollusks. Total length and body weight of fish varied between 9-34 cm (20.53 ± 6.90 cm) and 10-400 g (9125.94 ± 102.07 g), respectively. The index of relative importance (IRI%) showed the importance of rotifers over the other food items. Morisita's index of diet overlap indicated seasonal variations in catfish diets with summer and monsoon displaying the least overlap, while maximum overlap during monsoon and winter seasons. The non-metric multidimensional scaling (nMDS) indicated the close association between the food items available during summer and winter seasons with a significant difference among the seasons (ANOSIM, R = 0.638, P = 0.013). Levin’s niche breadth index arranged in the order of 0.88>0.81>0.78>0.63>0.43 for the size classes of V, IV, III, II and I, respectively. The PCA explained 95.39% of the total variance among the food items and fish size groups. Small-sized fish individuals displayed a greater correlation with food items suitable for their mouth size. In conclusion, the variety and frequency of food items recorded indicated considerable feeding plasticity and opportunistic feeding behavior with a shift from carnivorous to omnivorous feeding nature. This study could render useful information on the food and feeding habits of R. rita and provide background for preparing its diet for future aquaculture practices.

Esta investigação apresenta a alimentação e a atividade alimentar de bagres ribeirinhos Rita rita ameaçados de extinção, no período de fevereiro de 2017 a janeiro de 2018. Um total de 225 peixes foi analisado quanto ao conteúdo do estômago, caracterizando os itens alimentares dominantes e as características morfométricas. Os resultados apresentaram dez principais itens alimentares consumidos, preferencialmente escamas e ovos de peixes, teleósteos, copépodes, cladóceros, rotíferos e moluscos. O comprimento total e o peso corporal dos peixes variaram entre 9-34 cm (20,53 ± 6,90 cm) e 10-400 g (9125,94 ± 102,07 g), respectivamente. O índice de importância relativa (IRI%) mostrou a importância dos rotíferos sobre os demais itens alimentares. O índice de sobreposição de dieta de Morisita indicou variações sazonais nas dietas de bagres no verão e nas monções, exibindo a menor sobreposição, enquanto a sobreposição máxima ocorreu durante as estações das monções e do inverno. A escala multidimensional não métrica (nMDS) indicou a estreita associação entre os itens alimentares disponíveis durante o verão e o inverno, com uma diferença significativa entre as estações (ANOSIM, R = 0,638, P = 0,013). O índice de amplitude de nicho de Levin foi organizado na ordem de 0,88 > 0,81 > 0,78 > 0,63 > 0,43 para as classes de tamanho de V, IV, III, II e I, respectivamente. O PCA explicou 95,39% da variação total entre os itens alimentares e os grupos de tamanho de peixes. Peixes de pequeno porte apresentaram maior correlação com itens alimentares adequados ao tamanho da boca. Em conclusão, a variedade e a frequência dos itens alimentares registrados indicaram plasticidade alimentar considerável e comportamento alimentar oportunista, com uma mudança da natureza carnívora para onívora. Este estudo pode fornecer informações úteis sobre os hábitos alimentares e de alimentação de R. rita e apresentar subsídios para a preparação de sua dieta em futuras práticas de aquicultura.

Asunto(s)

RESUMEN

Abstract This investigation presents the food and feeding activity of and endangered riverine catfish Rita rita, during February 2017-January 2018. A total of 225 fish individuals was analyzed for stomach contents by characterizing the dominant food items and morphometric features. The results divulged ten major food items consumed, preferably fish scales and eggs, teleost fishes, copepods, cladocerans, rotifers, and mollusks. Total length and body weight of fish varied between 9-34 cm (20.53 ± 6.90 cm) and 10-400 g (9125.94 ± 102.07 g), respectively. The index of relative importance (IRI%) showed the importance of rotifers over the other food items. Morisitas index of diet overlap indicated seasonal variations in catfish diets with summer and monsoon displaying the least overlap, while maximum overlap during monsoon and winter seasons. The non-metric multidimensional scaling (nMDS) indicated the close association between the food items available during summer and winter seasons with a significant difference among the seasons (ANOSIM, R = 0.638, P = 0.013). Levins niche breadth index arranged in the order of 0.88>0.81>0.78>0.63>0.43 for the size classes of V, IV, III, II and I, respectively. The PCA explained 95.39% of the total variance among the food items and fish size groups. Small-sized fish individuals displayed a greater correlation with food items suitable for their mouth size. In conclusion, the variety and frequency of food items recorded indicated considerable feeding plasticity and opportunistic feeding behavior with a shift from carnivorous to omnivorous feeding nature. This study could render useful information on the food and feeding habits of R. rita and provide background for preparing its diet for future aquaculture practices.

Resumo Esta investigação apresenta a alimentação e a atividade alimentar de bagres ribeirinhos Rita rita ameaçados de extinção, no período de fevereiro de 2017 a janeiro de 2018. Um total de 225 peixes foi analisado quanto ao conteúdo do estômago, caracterizando os itens alimentares dominantes e as características morfométricas. Os resultados apresentaram dez principais itens alimentares consumidos, preferencialmente escamas e ovos de peixes, teleósteos, copépodes, cladóceros, rotíferos e moluscos. O comprimento total e o peso corporal dos peixes variaram entre 9-34 cm (20,53 ± 6,90 cm) e 10-400 g (9125,94 ± 102,07 g), respectivamente. O índice de importância relativa (IRI%) mostrou a importância dos rotíferos sobre os demais itens alimentares. O índice de sobreposição de dieta de Morisita indicou variações sazonais nas dietas de bagres no verão e nas monções, exibindo a menor sobreposição, enquanto a sobreposição máxima ocorreu durante as estações das monções e do inverno. A escala multidimensional não métrica (nMDS) indicou a estreita associação entre os itens alimentares disponíveis durante o verão e o inverno, com uma diferença significativa entre as estações (ANOSIM, R = 0,638, P = 0,013). O índice de amplitude de nicho de Levin foi organizado na ordem de 0,88 > 0,81 > 0,78 > 0,63 > 0,43 para as classes de tamanho de V, IV, III, II e I, respectivamente. O PCA explicou 95,39% da variação total entre os itens alimentares e os grupos de tamanho de peixes. Peixes de pequeno porte apresentaram maior correlação com itens alimentares adequados ao tamanho da boca. Em conclusão, a variedade e a frequência dos itens alimentares registrados indicaram plasticidade alimentar considerável e comportamento alimentar oportunista, com uma mudança da natureza carnívora para onívora. Este estudo pode fornecer informações úteis sobre os hábitos alimentares e de alimentação de R. rita e apresentar subsídios para a preparação de sua dieta em futuras práticas de aquicultura.

RESUMEN

This investigation presents the food and feeding activity of and endangered riverine catfish Rita rita, during February 2017-January 2018. A total of 225 fish individuals was analyzed for stomach contents by characterizing the dominant food items and morphometric features. The results divulged ten major food items consumed, preferably fish scales and eggs, teleost fishes, copepods, cladocerans, rotifers, and mollusks. Total length and body weight of fish varied between 9-34 cm (20.53 ± 6.90 cm) and 10-400 g (9125.94 ± 102.07 g), respectively. The index of relative importance (IRI%) showed the importance of rotifers over the other food items. Morisita's index of diet overlap indicated seasonal variations in catfish diets with summer and monsoon displaying the least overlap, while maximum overlap during monsoon and winter seasons. The non-metric multidimensional scaling (nMDS) indicated the close association between the food items available during summer and winter seasons with a significant difference among the seasons (ANOSIM, R = 0.638, P = 0.013). Levin's niche breadth index arranged in the order of 0.88>0.81>0.78>0.63>0.43 for the size classes of V, IV, III, II and I, respectively. The PCA explained 95.39% of the total variance among the food items and fish size groups. Small-sized fish individuals displayed a greater correlation with food items suitable for their mouth size. In conclusion, the variety and frequency of food items recorded indicated considerable feeding plasticity and opportunistic feeding behavior with a shift from carnivorous to omnivorous feeding nature. This study could render useful information on the food and feeding habits of R. rita and provide background for preparing its diet for future aquaculture practices.

Asunto(s)

RESUMEN

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gram-negative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2-8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr(+6) reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr(+6) (MIC 8.6-17.8 mM), the isolates showed tolerance to Ni(+2), Fe(+3), Cu(+2) and Co(+2) but were extremely sensitive to Hg(+2) followed by Cd(+2), Mn(+2) and Zn(+2). In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr(+6) in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr(+6) present in mine seepage when grown in mine seepage supplemented with VB concentrate.

RESUMEN

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gramnegative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2-8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr+6 reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6 (MIC 8.6-17.8 mM), the isolates showed tolerance to Ni+2, Fe+3, Cu+2 and Co+2 but were extremely sensitive to Hg+2 followed by Cd+2, Mn+2 and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6 in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6 present in mine seepage when grown in mine seepage supplemented with VB concentrate.(AU)

Asunto(s)

RESUMEN

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gramnegative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2-8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr+6 reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6 (MIC 8.6-17.8 mM), the isolates showed tolerance to Ni+2, Fe+3, Cu+2 and Co+2 but were extremely sensitive to Hg+2 followed by Cd+2, Mn+2 and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6 in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6 present in mine seepage when grown in mine seepage supplemented with VB concentrate

Asunto(s)