Duskytail grouper  (Epinephelus bleekeri)

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

The robust, elongate body of the duskytail grouper is brownish to purplish-grey in colour and covered with numerous small, yellow, orange or gold spots. While the dorsal fin and the upper third of the caudal fin are spotted, the lower two thirds of the caudal fin are dusky in colour, hence the common name. The anal, pectoral and pelvic fins are unspotted, as is the ventral surface of the body (2) (3).

The duskytail grouper has an Indo-Pacific distribution ranging from the Persian Gulf to Taiwan, Indonesia, and northern Australia (1).

Occurs on shallow rocky banks from depths of 30 to 104 metres, but is not known from well-developed coral reefs (1) (2) (3).

Very little is documented about the biology of the duskytail grouper, but like other Epinephelus species, it is probably a protogynous hermaphrodite, meaning that individuals begin mature life as female and change sex later to become male (2) (4). Epinephelus species tend to be voracious predators, with fish and crustaceans taken near the sea bottom forming the bulk of the prey (2) (5).

Owing to the commercial trawling of adults for food, and the removal of juveniles from the wild for mariculture, the duskytail grouper is thought to be no longer abundant in large parts of its range (1).

While there are no specific conservation measures in place for the duskytail grouper, this species does occur in some protected marine areas across its range (1).

For further information on the conservation of groupers see:

• Grouper and Wrasse Specialist Group:
  http://www.hku.hk/ecology/GroupersWrasses/iucnsg

• Anal: Referring to the anal fin, an unpaired fin on the under surface of a fish, behind the anus.
• Caudal fin: The tail fin of a fish.
• Crustaceans: Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
• Dorsal fin: The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
• Mariculture: The cultivation of marine organisms, for food and other products, in the open ocean, an enclosed section of the ocean, or in tanks and ponds filled with seawater.
• Pectoral: referring to the pectoral fins, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.
• Pelvic fins: In fish, the pair of fins found on the underside of the body.
• Protogynous hermaphrodite: An animal that begins its life cycle as a female. As the animal ages, based on internal or external triggers, it shifts sex to become a male animal.

1. IUCN Red List (April, 2009)
   http://www.iucnredlist.org/
2. Heemstra, P.C. and Randall, J.E. (1993) FAO Species Catalogue. Vol. 16: Groupers of the World. Food and Agricultural Organization, Rome.
3. Polovina, J.J. and Ralston, S. (1987) Tropical snappers and groupers: biology and fisheries management. Westview Press, Boulder, Colorado.
4. Randall, J.E. (1994) Coastal fishes of Oman. University of Hawaii Press, Honolulu.
5. Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.