Development of a Sustainable Polyculture Technique Using Asian Watergrass as Fish Feed in the Southern Coastal Region of Bangladesh

Abstract

Globally, the quality and high cost of fish feed are vital issues for the development of sustainable aquaculture and food security. Present study was investigated in 4 treatments to find out the compatible species combination for polyculture using Asian watergrass as natural feed for fish in the tidally flooded coastal wetlands for a period of 6 months. Grass carp, common carp, tilapia, mrigal and silver barb were stocked in different species combination with an identical density of 12500 fish ha-1. In all treatments, grass carp and common carp were commonly stocked but other 3 species were disparate to stock among the treatments. Important water quality parameters were monitored those were suitable and acceptable range for aquaculture. The survival of fishes varied from 66.7±8.3 to 91.2±2.9% irrespective of fish species. The total fish production was found significantly higher (p<0.05), 5579.04±238.74 kg ha-1 in T3 followed by 4582.21±200.01 kg ha-1 in T2, 4571.52±189.78 kg ha-1 in T4 and 4448.37±247.26 kg ha-1 in T1 respectively. The results demonstrate that the combination of grass carp, common carp, tilapia, and silver barb in T3 was ideal compatible species for polyculture in coastal wetlands. This technique should be applied in haor, baor, beel, canals, and other water-logged areas pervaded by climate changes.