Title	Study in the use of artificial reefs and edible shellfish to reduce the environment impacts of fish culture zones in Hong Kong
Year	2001-2003
Organization	City University of Hong Kong
Objective	To investigate the feasibility of using ARs as biofilters.
Study area	Kau Sai Fish Culture Zone
Method	MThe trial is being conducted with Green-lipped mussel . Deployment of the biofilters took place in April 2002. Organisms colonizing the biofilters will be sampled bimonthly for two years. The study will also investigate the food quality of the cultured Green-lipped mussel for human consumption and the feasibility of marketing cultured shellfish produced in Hong Kong fish culture zones.
Results	1. Fish farming activities resulted in localized nutrient enrichment in the vicinity of the fish culture zone. 2. No significant difference was observed in the settlement of fouling organisms at the unidirectional and bidirectional flow designs of the ARs used in the study. 3. AR systems can be used as efficient biofilters to remove nutrients through the filter feeding mechanism by the fouling organisms settling on the AR surface. 4. Filter-feeding organisms on the surface of ARs can efficiently feed and assimilate the fish-farming derived organic wastes before them settling onto seabed. 5.The removal of carbon, nitrogen and phosphorus from seawater by the fouling organisms on the AR biofiltration units (total surface area of 4,000m 2 ) in the study was estimated at 6.4, 1.7 and 0.3 kg day -1 , respectively, and the filtration capacity of seawater was estimated at 8,736 m 3 day -1 . 6. ARs deployed on the seabed are not ideal facilities for commercial shellfish farming activities. 7. ARs can evidently improve the sediment environment and hence, the structure of benthic communities in the vicinity of the fish rafts.
Reference	NA