Water quality in intensive climbing perch ponds (Anabas testudineus) and suggestion for better management of wastewater discharge

Abstract

Climbing perch (Anabas testudineus) is widely distributed in the Mekong Delta and is a favorite dish of several families. Due to the severe decline of wild climbing perch polulation, semi-intensive cultivation using natural foods does not meet demand and economic efficiency is not high. Therefore, intensive climbing perch cultivation has been strongly developed in Can Tho city, Viet Nam in order to diversify food sources fulfilling consumer demand. Intensive farming model takes advantage of small area of water surface, high density of fingerlings, and high rate of feeding thus speeding fish growth and harvesting period. However, intensive farming can lead to environmental problems due to leftover feeds. This study aimed to assess the water quality in 6 intensive climbing perch culturing ponds in which 3 ponds using home-made feed and 3 ponds using industrial feed. River water samples were collected at the same time as control to compare quality of water with the intensive climbing perch cultivating ponds. The results show that water quality in the intensive climbing perch culturing ponds were heavily organically polluted (DO was low while BOD and COD were very high) in which the use of home-made feeds for intensive aquaculture resulting in more environmental problems. Wastewater from intensive culturing ponds if directly discharged to the river would cause eutrophication and seriously pollute river water due to high concentrations of NH₄⁺-N, TKN and TP. Replacement of home-made feed by other suitable feed and treatment of wastewater from the ponds before discharging into receiving source were recommended to prevent environmental problems. Master planning and raising awareness of law enforcement and policies on environmental protection are urgently needed to reduce environmental pollution in aquaculture.