Title	SCUBA Fisheries Assessment of Artificial Reefs
Year	1999-2000
Organization	Management Services to the Environment
Objective	Compare fish colonization on different types of ARs and controls.
Study area	Hoi Ha Wan and Yan Chau Tong Marine Parks
Method	158 visual censuses involving timed swims, using closed circuit rebreathers, were carried out at tyre, vessel, quarry rock and concrete ARs and four other control sites between March 1999 and December 2000.
Results	Comparing the observed fish abundance and diversity at the study sites, the following conclusions were drawn: 1. ARs deployed on mud bottom support a more abundant and diverse fish population than mud bottom alone. 2. Rocky shore control sites have similar diversity to ARs but less abundant. 3. Artificial reefs support higher value fish than rocky shore and mud bottom control sites. 4. Quarry rock ARs become colonized with fish more rapidly and have higher abundance and diversity than other types of ARs. 5. No apparent differences between abundance found on tyre-, concrete- and vessel ARs. 6. Snapper, grunt and seabream have been particularly successful on all types of ARs. 7. Grouper have established on ARs in low numbers. 8. ARs in the marine parks, by providing complex habitat at depths below 6m, served to enhance reef fish. By preventing bottom trawling, AR also improved conditions for non-reef fishes. 9. Fish/AR interactions