The situation of aquaculture and the characteristics of hydrobiology in water areas in Gialam district, Hanoi

Abstract

A survey was conducted in three communes, viz. Dong Du, Dinh Xuyen, and Dang Xa in Gialam district of Hanoi to investigate the present situation of aquaculture and ecological characteristics of the water areas. Water samples were taken ponds, lakes and low-lying fields.  Results  showed that fish productivity and the effect of aquaculture was not proportionale to the potentiality. The reasons were that the farmining systems were mainly semi-intensive and the cultured fish species were common ones, viz. Grass carp (Ctenopharyngodon idellus), Mud carp (Cirrhina molitorella), Silver carp (Hypophthalmichthys sp.). In addition density of fish was too high andthe low-lying fields were rarely used for aquculture. The study identified 36 species of zooplankton, 28 species of phytoplankton, most of popular species of benthos in the water areas of North of Vietnam were found here but Olygochaeta and larvae of mosquito species predominated. Although the number of species of plankton and benthos was large, the their density and the biomass were low.