Assessment of water quality and its effect on prawn abundance in three tributaries of Shiwalik rivers: Chenab and Ravi of Jammu, India—a case study

Abstract

The freshwater rivers from Shiwalik Himalayas have abundant prawn resources of high economic value and play a major role in the livelihood of local fishermen. The present study aimed to determine the variation in prawn abundance explained by changes in water quality among three different streams (Gho Manhasa stream, Chadwal stream and Nagri stream). The highest abundance of prawns was found in the Gho Manhasa during the premonsoon season and lowest in the Chadwal stream during the monsoon season. Chadwal stream witnessed maximum anthropogenic activities resulting in the decline of the water quality affecting prawn fauna. Cluster analysis based on similarity in terms of prawn abundance revealed that the Chadwal stream is different from the other two streams whereas non-metric multidimensional scaling plot based on species abundance corresponding to different seasons and physiochemical parameters showed the water quality of the monsoon season of the Chadwal stream to be extremely different. Principal component analysis showed clear separation across various sites and seasons based on physicochemical parameters. Karl Pearson correlation coefficient and canonical correspondence analysis indicated that the turbidity, total dissolved solids, nitrate, chloride, calcium, magnesium and dissolved oxygen are significant parameters influencing the abundance of prawns. The population of Macrobrachium dayanum and Macrobrachium kistnense was very less in the Chadwal stream owing to unfavorable physicochemical parameters. Therefore, conservation measures are suggested which should be immediately implemented before the streams witness a further decline in their populations.