Comparative study of seasonal variation in bacterial flora concomitant with farm raised fingerlings of Cyprinus carpio at tarai region of Uttarakhand.

The bacterial infection is an important economic and limiting factor in intensive fish production. The present study focuses on investigation of the bacterial population associated with farmed common carp fingerlings, its environment and limnological quality of pond, during winter and summer season. It was found that the bacterial count in the pond sediment (6.40 cfu x 10(4)) was about 10 times higher in comparison of pond water (6.93 cfu x 10(3)). Further, the intestinal bacterial count was about 100 times higher (6.67 cfu x 10(5)) during winter and 1000 times higher (2.33 cfu x 10(6)) during summer season in comparison to the surfacial skin of fish during winter and summer (3.39 and 8.87 cfu x 10(3)), respectively. The isolated bacteria were both Gram negative and Gram positive, mostly aerobic rods. Furthermore, the temperature showed a significant relation with the bacterial counts of pond water. In the summer season, higher bacterial counts (8.72 cfu x 10(3)) were recorded as compared to winter (5.13 cfu x 10(3)). The dominant bacteria isolated from the sample of pond water, pond sediment and fish were identified as Aeromonas hydrophila, Pseudomonas fluorescens, Pseudomonas sp., Flavobacter sp., Bacillus sp., Micrococcus sp., Corynebacterium sp. Moreover, the bacterial density was dependent on C:N values, and the optimum range of C: N ratio was found between 16-23, for the carp culture ponds. Among the isolated bacterial flora, the presence of strains which were well known for their probiotic properties suggested an autochthonous source for use in aquaculture. Further, analysis of various physico-chemical parameters of pond water revealed that they were within the suitable range for the freshwater fish culture throughout farming phase.

Comparative organoleptic quality of Indian major carps collected from pond and reservoir.

An attempt was made to distinguish the possible organoleptic differences between the pond reared and wild fish species of reservoirs and correlate these with the physicochemical characteristics of water bodies. The texture was found to firmer in wild varieties of fishes than pond reared fish, with best in Catla catla followed by Labeo rohita and Cirrhinus mrigala. All the cultured fishes had lighter colour than wild fish species which were darker in appearance. Comparatively, higher dissolved oxygen and transparency levels with low temperature and alkalinity levels were found in reservoirs. Hydrobiologically, the efficient ecosystem of reservoir was responsible for stronger texture and dark colouration in wild fish species. The fishes from reservoir exhibit tendency to lead active and agile life, comparatively the fishes from ponds are docile. Reservoirs have the potential of enhanced quality fish production.

Remote sensing study on geomorphological degradation of Sarda Sagar reservoir.

An attempt was made to estimate the geomorphological degradation due to sedimentation of Sarda Sagar reservoir, located in Pilibhit and Udhamsingh Nagar, district of Uttar Pradash and Uttarakhand respectively. The study was conducted using multidated IRS LIISS III remote sensing data for the year 2006-2007. Using satellite images of different seasons during 2006-2007, a total of 45.23 million m3 volume of sedimentation was computed in-between the 183.704 m and 190.504 m elevation. The reservoir has lost 11.72 % of the total capacity of water storage and an average rate of sedimentation was calculated as 0.26 % per year. Due to this sedimentation the new feeder channel of Sarda Sagar is choked with silt and the water flow from this channel has almost stopped. The morphology of the reservoir has been changed due to sedimentation during the period 1962 to 2007. This has altered breeding ground of fishes since important indigenous fish species which need flowing water condition to perform the breeding. This study would be helpful for the planners to manage the reservoir and to assess the biological productivity.

Efficacy of Azadirachta indica extracts against Boophilus microplus.

Extracts were prepared from leaf, bark, and seed of Azadirachta indica, leaf and seed of Prunus persica, bark of Mangifera indica, and leaf of Psidium guajava and were evaluated against Boophilus microplus. Of the eight extracts screened, the extracts prepared from the A. indica seed showed very high level of efficacy (80%) after 5 h of treatment. Besides the immediate effect on adult ticks, the egg-laying properties of the survived ticks was also assessed, and a significant reduction (P < 0.01) in the reproductive index of ticks fed on animals treated with A. indica seed extracts was noted in comparison to control. The efficacy of the neem seed extracts was compared with the commonly used synthetic pyrethroids, and comparable efficacy against B. microplus fed on animals treated with neem seed extracts and acaricide treated was noted. The possibility of using the extracts in IPM format for the management of ticks is discussed.