Skip to content

Aquaculture environment

Water quality monitoring

Water quality is an important factor affecting the productivity of mariculture operations in Hong Kong. This department conducts regular water quality monitoring at all fish culture zones in Hong Kong to check whether the water quality is suitable for fish culture.

Sampling at fish culture zone
Sampling at fish culture zone
Technical seminars for fish farmers on water quality monitoring and management are held regularly.
Technical seminar on aquaculture

Apart from conducting regular water quality monitoring at all fish culture zones, AFCD has setup real time water quality monitoring systems at 16 fish culture zones to monitor the water quality continuously for early detection of abnormality and issuance of alerts to mariculturists.

Click here to view real time water quality at fish culture zones.

Red tide management

AFCD has implemented a long term phytoplankton monitoring programme with a view to detecting the presence of toxic algae or the development of harmful algal blooms and minimising the impact on mariculture. We now conduct weekly seawater sampling at 6 core fish culture zones, fortnightly at another 5 fish culture zones and 5 offshore stations and once every 3 months at the remaining 15 fish culture zones for the analysis of phytoplankton. Sampling frequency will be increased when harmful algal species or abnormally high phytoplankton populations are detected. Prompt alerts will be issued to mariculturists where required.

Map showing the phytoplankton sampling locations

Click here to see the sampling stations.

An outreach team has also been established to provide rapid responses to red tide/harmful algal bloom (HAB) reports. We will conduct site investigation, collect and analyse water samples, identify the red tide causative species, estimate the area affected and assess the potential risk on mariculture. AFCD will disseminate the information and findings to relevant departments for their appropriate follow-up actions. If the red tide occurs at or near fish culture zones, the concerned mariculturists will be alerted to take appropriate precautionary measures to minimise the impact caused by red tide.


Plankton sampling
Microscopic identification of plankton species


The latest red tide situation in Hong Kong waters will be updated every week on the Hong Kong Red Tide Information Network. You are welcome to visit the Hong Kong Red Tide Information Network (http://www.afcd.gov.hk/english/fisheries/hkredtide/redtide.html) to obtain more information about red tide.

Impacts of development works

Assessment of potential environmental impact on aquaculture is required for development projects involving fish culture zones, fish ponds and oyster beds, in accordance with the Environmental Impact Assessment Ordinance (Cap. 499). Criteria and guidelines for fisheries impact assessment can be found in Annexes 9 and 17 of the Technical Memorandum on Environmental Impact Assessment Process.

Construction work at sea
Dredging operation

The ex-gratia allowance is payable to mariculturists, pond fish farmers and oyster farmers who are adversely affected by development projects. The department assists in the administration of ex-gratia allowance payment by providing technical assistance in the assessment and professional advice.

Water quality monitoring frequency would be increased when there are development works that may affect fish culture zones nearby. Upon receipt of reports of fish kill or complaints of water quality changes at fish water zones or the nearby waters, investigations will be carried out and advice on appropriate mitigatory measures to minimise loss will be provided to the fish farmers.


Farm visit
Sampling at fish culture zone



  Telephone No.
Water Quality Monitoring at Fish Culture Zones 2150 7084
Report of Red Tide 2150 7124
Fisheries Impact Assessment 3426 3133
Ex-gratia Allowance 2150 6634
Back  Back to Top