Fish diversity in Oxbow lake is adversely impacted due to diverse anthropogenic activities like over-exploitation, indiscriminate use of fine meshed fishing gears, jute retting etc. To quantify the impact of such anthropogenic activities on fish diversity and aquatic health, a survey with seasonal analysis of diversity indices, relative frequencies and abundance status of native fish populations was conducted from April 2013 to March 2014 in a semi closed Oxbow lake in Nadia district in eastern India. The level of p<0.05 was accepted as statistical significance. Of the 33 native fish species recorded 33% belonging to 8 orders and 17 families fell under vulnerable or endangered categories. Native species like Amblypharyngodon mola, Chanda nama, Pethia ticto and Notopterus notopterus, Colisa fasciata, P. ticto, were the most dominant and frequent fishes. Shannon-Weiner diversity index was decreased by 41% by precipitating impact of monsoonal anthropogenic activities during post-monsoon. Low native fish diversity indices are pointers to poor ecosystem health status owing to intense adverse activities like jute retting, indiscriminate fishing aggravated by influx of turbid water from the river Ganga following episodic flood events during monsoon. Regulation and prevention of such anthropogenic activities are urgently warranted for sustainable conservation and management of the Oxbow lake.

Abstract:The habitat analysis of stork-billed kingfisher (Pelargopsis capensis Linnaeus, 1766) and pied kingfisher (Ceryle rudis Linnaeus, 1758) was done at the Chittagong University Campus, Chittagong, Bangladesh during January 2011 to December 2013. The both kingfisher species used five types of habitat (pond, lake, stream, agricultural land/channel and tree), of which trees were used maximum (43.23%) and agricultural lands/channels were minimum (3.76%) by stork-billed kingfisher; whereas pied kingfisher spent the highest time (40.66%) in the streams and the lowest (11.67%) in the agricultural lands/channels. Four types of perching places (fence, wire, bamboo and tree) were used by both kingfisher species, of which trees were used maximum (68.89%) and wires minimum (2.78%) by stork-billed kingfisher; while pied kingfisher spent the highest (53.43%) time on fences and the lowest (4.78%) on wires.

The activity patterns of pied kingfisher (Ceryle rudis Linnaeus, 1758) and stork-billed kingfisher (Pelargopsis capensis Linnaeus, 1766) were studied in the Chittagong University Campus, Chittagong, Bangladesh, during January 2011 to December 2013. Eight activities (resting/perching, bathing, flying, feeding, calling, preening, hovering and diving) were observed in this study, of which pied kingfisher performed all eight activities and stork-billed kingfisher performed all except bathing and hovering. Both kingfisher species spent the maximum (pied kingfisher: 31.87%; stork-billed kingfisher: 45.82%) time in resting/perching and the minimum (pied kingfisher: 4.83%; stork-billed kingfisher: 1.90%) in preening. Pied kingfishers were mostly (28.3%) active during 0700 and 0900 h and stork- billed kingfishers were more (31.17%) active in between 0901-1100 h. Pied kingfishers spent their highest (9.01%) time in different activities in August and the lowest (7.68%) in February, whereas storkbilled kingfishers spent the maximum (8.69%) time in March and the minimum (7.80%) in May.Bangladesh J. Zool. 42(2): 191-203, 2014