One of the most abundant and widespread groupers, the blacktip grouper is a robust predatory fish found in the Indian and western Pacific Oceans. Highly variable in colour, the body of the blacktip grouper ranges from pale greenish-grey to pale reddish-yellow or scarlet, usually with five dusky to red vertical bars on the body, fading to pale or white on the underside (2)(3). The upperside of the head is dark reddish-brown, often with blotches or bands of similar colour and a narrow blackish edge around the eye (2)(3). The fins are reddish-orange, pale yellowish-green or greenish brown, with a blackish-brown line at the base of the dorsal fin and black triangles at the tip of each of the eleven spines, a feature that gives the blacktip grouper its name (2)(3)(4)(5). This fish has a slender body, with a slightly truncated and rounded tail fin (4)(6). The body is around a third deep as it is long, and large, conspicuous eyes sit behind a gaping jaw armed with two or three rows of strong, slender teeth (2)(3)(6).
Also known as
banded reef cod, banded rock cod, black-tipped grouper, black-tipped rockcod, black-tipped rock-cod, footballer cod, golden grouper, red banned grouper, red-banded grouper, redbarred roccod, rock cod, striped grouper.
Despite being a relatively abundant and widespread species, very little is known about the biology of the blacktip grouper. However, unlike many other members of the genusEpinephelus, which typically display the remarkable ability of being able to change their sex, the blacktip grouper is thought to have separate sexes. Females have been observed forming spawning aggregations, and the resultant offspring are thought to have a fast growth rate, reaching sexual maturity at around 12 centimetres in length, with a life expectancy of up to 19 years (1). This predatory fish largely feeds on other fish, crabs and octopuses (2).
One of the most widely distributed grouper species, the blacktip grouper is found throughout the Indian and western Pacific Oceans. In the Indian Ocean it is found from the Red Sea in the north, south to South Africa and east towards western Australia. In the Pacific Ocean, it ranges from Japan and Korea in the north, south to south Queensland, Australia and east to the Pitcairn Islands. Within this range, the blacktip grouper occurs in the waters around almost every tropical and sub-tropical island, although it appears to be absent from the Arabian Gulf (1)(2).
The blacktip grouper inhabits coral reefs and rocky bottoms from the shoreline down to a depth of around 160 metres. Although most abundant on the outer reef slopes, it is also found in sheltered bays, lagoons and seagrass beds (1)(2).
The blacktip grouper is considered one of the most common groupers and is currently not threatened with extinction. However, there are a number of distinct, isolated populations which are vulnerable to a variety of threats, and, consequently, this fish is in decline in some areas (1). The greatest threat to the blacktip grouper is the loss of its coral reef habitat to coral bleaching events, where the corals symbiotic algae are expelled, leaving the corals vulnerable and weak to a variety of harmful of diseases, with these events likely to increase in frequency due to global climate change (1)(7). This threat is compounded by dynamite and poison fishing, both of which also threaten its habitat (1). The blacktip grouper is also widely caught for food due to its abundance in shallow waters (2). Although this exploitation is likely to be small-scale, information is limited due to confusion in distinguishing this species from other groupers. Fishing catches of this species have dropped by around 40 percent on the island of Réunion in the Indian Ocean since 1995, while catches in the Pacific have dropped by around 25 percent in the last 50 years, and by over two thirds in Japan between 1989 and 2005 (1).
The blacktip grouper is protected in a number of marine reserves across its range, including the KwaZulu-Natal Marine Protected Area in South Africa, in which fishing is strictly prohibited. Fisheries are also regulated in some areas of the South African and Mozambique coastline, where the size and number of blacktip groupers caught is limited (1). In addition, this species will benefit from proposed measures to develop a system of reserve management areas in the Seychelles, in which the level of fishing will be regulated and monitored to ensure it is maintained at sustainable levels (8).
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The unpaired fin found on the back of the body of fish.
A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
The production or depositing of eggs in water.
Describes a relationship in which two organisms form a close association. The term is now usually used only for associations that benefit both organisms (a mutualism).
Heemstra, P.C. and Randall, J.E. (1993) FAO Species Catalogue. Volume 16. Groupers of the World (Family Serranidae, Subfamily Epinephelinae). An Annotated and Illustrated Catalogue of the Grouper, Rockcod, Hind, Coral Grouper, and Lyretail Species Known to Date. FAO Fisheries Synopsis No. 125, Vol. 16. Food and Agriculture Organisation of the United Nations, Rome.
Smith, M.M. and Heemstra, P.C. (2003) Smiths’ Sea Fishes. Struik Publishers, Cape Town, South Africa.
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