Camouflage grouper  (Epinephelus polyphekadion)

Classified as Near Threatened (NT) on the IUCN Red List (1).

A species with a fascinating life history, the camouflage grouper gets its name from its distinctive patterning, which helps it to blend into its coral habitat. It is pale to dark brown in colour with darker brown spots and irregular cream patches on the body (2). The  mouth and jaws are enormous and bear two to three rows of small, spiky teeth (2), making it a somewhat frightening looking fish face-on. Male and female camouflage groupers are normally hard to distinguish (2), except during the breeding season when the female can be recognised by a swollen belly, which is full of eggs (3).

The camouflage grouper has one of the largest distribution ranges of all the Indo-Pacific groupers (2). Its range extends from the east coast of Africa, north to the Red Sea, across to southern Japan and Queensland, and as far east as French Polynesia (2).  

The camouflage grouper is a near-shore fish associated with coral reefs (2). It is found in highest abundance around islands and atolls (2).

Probably the most interesting aspect of the biology of the camouflage grouper is that it is a protogynous hermaphrodite, which means that every individual begins life as a female and then changes into a male as it grows (3). To reproduce, camouflage groupers gather together in huge groups of hundreds or thousands of fish, to release eggs and sperm into the water column. This event, known as a spawning aggregation, takes place over a two month period between February and April (4). Female camouflage groupers typically outnumber males at a spawning aggregation (4), and can be identified by their bumpy, distended bellies full of hydrated eggs (3). Males present at a spawning aggregation have been observed taking part in what is thought to be competitive fighting, in which competitors press their mouths together (3). While spawning, the camouflage grouper enters a trance or stupor, unfortunately making it easier for divers or fishermen to approach (2).

The camouflage grouper feeds primarily on crustaceans and small fish (5).

The spawning behaviour of the camouflage grouper means that there are large numbers of fish in certain areas at predictable times, making them a valuable target for fishermen.In some areas, locals hunt the camouflage grouper using spear fishing techniques (6), but the greater threat to this species comes from commercial fishing which takes huge numbers of camouflage groupers out of the oceans from spawning aggregations (4). Whilst no-one is certain of the implications of this large-scale commercial fishing (7), this species is known to be one of the top three groupers taken by fisheries in Japan (8) and Palau (9).

When the camouflage grouper is brought to the surface waters, the great reduction in pressure causes gas expansion in the fish’s swim bladder and is potentially fatal. However, the fishermen puncture the swim bladder using a hypodermic needle in order to keep the fish alive (8). Camouflage groupers are worth more alive, forming part of the Live Reef Fish Food Trade, a billion-dollars-per-year industry (7). Many are then taken to Hong Kong and sold to wealthy restaurants in China, where groupers are one of the most sought-after live fish dishes (7).

Due to the camouflage grouper’s enormous range and the large number of offspring it produces, it was once thought that this fish would not be in danger of becoming threatened. However, due to overfishing this species is now listed as Near Threatened on the IUCN Red List (1). A number of conservation actions are taking place for the camouflage grouper throughout its range, such as a ban on commercial trade in this species during the spawning season in Pohnpei (Micronesia) and the Republic of Palau (3) (4), and various fishing restrictions in Australia, the Solomon Islands and New Caledonia (1).

View information on this species at the UNEP World Conservation Monitoring Centre.

To learn more about the conservation of species that form spawning aggregations visit:

• Society for the Conservation of Reef Fish Aggregations:
  http://www.scrfa.org