Fish assemblage and structure as well as hydrological parameters at Karatoya Fish Sanctuary, Panchagarh, Bangladesh

Abstract Spatiotemporal variation in fish assemblage structure was conducted from January to December 2015 in order to know the impacts of sanctuary on ichthyo-faunal diversity with its indices and major hydrological factors from six sampling stations of Karatoya fish sanctuary sectioned in the river Karatoya. A total of 69 fish species was obtained from this sanctuary including 21 threatened species where Aspidoparia jaya, Pethia ticto, Puntius sophore, Canthophrys gongota and Barilius barna was the major contributory species (> 4.17%) both in space and time. The uppermost species richness and abundance were viewed in January and lowest in May. Based on analysis of similarities (ANOSIM), fish assemblages were significantly different equally in station (P < 0.001, R = 0.15) and month (P < 0.001, R = 0.62). Through two-dimensional nonmetric multidimensional scaling (nMDS) and cluster analysis based on Bray-Curtis similarity index, assemblages were alienated into two groups at a value of 42% and 28% partition for station and month, respectively. Canonical Correspondence Analysis (CCA) recognized considerable relations between a number of fishes and hydrological parameters where dissolved oxygen (mg/l) and water temperature (ºC) were the main leading factors in shaping fish assemblage structure.