Strengthen monitoring of water quality in aquaculture areas

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Water quality is suitable for aquaculture

The province currently has 32,000 hectares of water surface for aquaculture, of which the freshwater aquaculture area accounts for the majority with more than 30,000 hectares, the rest is brackish water. With the goal of monitoring the quality of water sources, promptly making recommendations to aquaculture farmers, over the years, Dong Nai has always carried out water quality monitoring in aquaculture areas.

According to the Department of Natural Resources and Environment, in 2019, Dong Nai has implemented collecting water samples to warn the environment and aquatic epidemics in points in the province, including: fish raft area on Cai river (Bien Hoa city) with 12 times; Tri An lake area, La Nga’s breeding rafts (Dinh Quan district) with 16 times; Mangrove area of Long Thanh and Nhon Trach Districts with 10 times and shrimp and fish ponds in Tra Co (Tan Phu District); Thien Tan and Ma Da communes (Vinh Cuu District); La Nga and Phu Ngoc communes (Dinh Quan District) and Phuoc An Commune (Nhon Trach District).

The monitoring results has shown that most of the water quality environmental monitoring parameters such as temperature, salinity and pH are suitable for aquaculture. However, at some monitoring points, many parameters still exceed the permitted level (according to QCVN 08-MT2015 / BTNMT).

Specifically, as of November 2019, the dissolved oxygen (DO) content tends to decrease, which is not suitable for aquaculture in some areas such as: fish raft area on Cai river, mangrove area of Long Thanh and Nhon Trach Districts. Especially, in the area of fish rafts concentrated on Cai river, DO content at this time was recorded not reaching the permitted level.

 Increase the frequency of monitoring​

La Nga’s breeding rafts (Dinh Quan district) is one of the areas where water quality monitoring will be carried out at high frequency.

In order to closely monitor the quality of water resources, the Provincial People's Committee recently issued a plan for environmental monitoring and warning in aquaculture in the province in 2020. There are 4 major aquaculture areas that will perform water quality monitoring including: fish raft area on Cai river; Dinh Quan district’s breeding rafts (including La Nga, Phu Ngoc, Thanh Son and Ngoc Dinh communes); mangrove area of Long Thanh and Nhon Trach Districts area intensive farming in Vinh Cuu, Dinh Quan and Tan Phu Districts.

Deputy Chairman of the provincial People's Committee Vo Van Chanh said that the monitoring aims to assess the quality changes of the aquaculture environment on the key areas to be monitored. Therby promptly give warnings and recommendations to farmers when there are abnormal changes in the environment or the risk of environmental pollution or degradation in aquaculture. “Monitoring results combined with recommendations on stocking schedules will help farmers to understand the water environment, identify adverse environmental factors to help farmers plan to get water into the pond, treat the water, stock them, and manage the culture area appropriately.” - said Mr. Vo Van Chanh.

Compared to 2019, the frequency of water quality monitoring in aquaculture areas has also increased. Specifically, for the area of fish rafts on Cai River, it will be done 24 times a year; fish farming area in Dinh Quan District 18 times/year; mangrove area of Long Thanh and Nhon Trach Districts 24 times a year, and areas of intensive ponds in Vinh Cuu, Dinh Quan and Tan Phu Districts will be done 6 times/year.

According to Tran Trong Toan, Director of the Environmental Protection Sub-Department (DONRE), the frequency of monitoring in areas is based on the principle that high risk of water pollution will be monitored continuously, thereby timely detect abnormalities in the water environment, give appropriate warnings, helping aquaculture farmers to promptly respond. In places where water quality is good and monitoring frequency is reduced, it is still possible for authorities to detect abnormalities in time.

Mr. Le Van Goi, Deputy Director of the Department of Agriculture and Rural Development, said that strengthening the monitoring and supervision in aquaculture areas in the province is very necessary. Currently, aquaculture is a fast growing sector of the provincial agriculture sector. However, in recent years, the ‘fish kill’ of aquaculture products has also caused serious damages to farmers, mainly due to the quality of water resources for aquaculture. “The increased monitoring will help detect timely the risk of pollution, thereby giving warnings to farmers to minimize damage” - Mr. Le Van Call emphasized.

According to the provincial People's Committee, the total budget for implementing the environmental monitoring and warning plan in aquaculture in the province in 2020 is over VND 470 million.

By  Nam Vu