Characterisation of fish communities at Scott Reefs, Seringapatam Reef and the Rowley Shoals, Western Australia

In September/October 1993, fish communities at North Scott Reef, South Scott Reef, Seringapatam Reef and the Rowley Shoals (Mermaid Reef, Clerke Reef and Imperieuse Reef) were surveyed.

Fish population censuses for a number of reef fish families (Chaetodontidae, Pomacentridae, Acanthuridae, Scaridae, Labridae, Caesionidae, Siganidae, Pomacanthidae and Zanclidae) were carried out by trained divers at a number of outer reef slope and lagoon sites at each reef. The log5 abundance of fish species was recorded during 45-minute SCUBA swims in which the observer swam a zig-zag course along an approximately 250m long section of the reef within a depth range of 0-12m.

Absolute counts of snappers, emperors, cods and butterfly fish (Lutjanidae, Lethrinidae, Serranidae and Chaetodontidae) were also made at outer reef slope and lagoon sites.

Additional fish counts of Labridae and Pomacentridae were made at 3 sites at South Scott Reef using standardised counting methods developed for long-term monitoring of fish populations on the Great Barrier Reef. This technique involved counting fish along 5 replicate 50m x 2m transects per site at a depth of approximately 6m.

In addition to the quantitative counts of the groups mentioned above, lists of all species of fish observed at each site were compiled.