Publication Date


Series Number

Fisheries Research Report No. 208


Western Australian Department of Fisheries


1 921258 92 6


1035 - 4549


The small islands of the Indian Ocean Territories are isolated reefs in an expanse of open ocean of abyssal depth. The majority of marine species that live on their reefs and lagoons have settled there from remote locations. Colonising individuals are presumed to have come to the island as the result of unusual weather and current conditions and form populations that are, necessarily, largely self-sustaining. The isolated populations that make up many of the fish and invertebrate stocks at the Cocos (Keeling) and Christmas Islands rely almost exclusively on larvae returning to their home reef to settle, grow and ultimately reproduce to maintain their numbers. This insularity is, in many cases, a direct implication of the constraints imposed on species by their own biology and reproductive strategy. In the event that a species is lost from either of the islands, recolonisation is dependent on reoccurrence of the unusual colonisation events. The vulnerability of these stocks is further exacerbated by the tiny size of the islands. The small reefs and lagoon only have the capacity to sustain small stocks of fish and invertebrates, ones that are very much at risk to chance events such as localised overfishing, anoxia events or over predation.

Number of Pages



Christmas Island - Indian Ocean; Cocos (Keeling) Islands - Indian Ocean; Marine resources; Exploitation; Geographical isolation; Stock assessment; Fishery biology; Fishery management; Marine fisheries