FishFish

Fish

About 528 species of fish have been recorded in the seas of the Cocos (Keeling) Islands (Berry 1989). Compared with other oceanic atolls, the islands’ fish fauna appears impoverished (Allen 1989). Reasons for this may include the small physical size of the islands, the relative isolation and lack of surrounding island ‘stepping stones’, and limited surveys of fish (Allen 1989). Most fish found at Cocos (Keeling) have distributions that cover large areas of the Indo-Pacific region (Allen 1989). However, recent genetic research has shown at least 4 species to be hybridising . This is believed to be the result of Cocos (Keeling) Islands’ location at the confluence of the western Pacific and eastern Indian Ocean biogeographic provinces (Choat 2003, pers comm.). There is no confirmed endemism in the Cocos (Keeling) Islands fish fauna, although one angelfish, Centropyge joculator, is known only from Cocos (Keeling) and Christmas Island. An undescribed goby of the genus Trimma may have the same distribution (Allen and Smith-Vaniz 1994).

Substantial populations of both butterfly fish and sharks (black-tip, white-tip and grey reef) in the Park provide a good indication of a healthy fish fauna. Whale sharks are also occasionally seen as they migrate past the atolls. Comparisons made between Cocos (Keeling) Islands and other Indo-Pacific atolls reinforce the notion of Cocos as one of the last areas of pristine reef systems in the world (Choat 2003, pers. comm.).

Table 3 lists the fish species of Cocos (Keeling) Islands.