The humphead wrasse (Cheilinus undulatus) is a wrasse that is mainly found in coral reefs in the Indo-Pacific region. It is also known as the Maori wrasse, Napoleon wrasse, Napoleonfish; or "So Mei" 蘇眉 (Cantonese) and "Mameng" (Filipino).

Description

The humphead wrasse is the largest living member of the family Labridae, with males reaching 6 feet (2 m) in length, while females rarely exceed about 3 feet (1 m). It has thick, fleshy lips and a hump that forms on its head above the eyes, becoming more prominent as the fish ages. Males range from a bright electric blue to green, a purplish blue, or a relatively dull blue/green. Juveniles and females are red-orange above, and red-orange to white below. Some males grow very large, with one unconfirmed report of a Humphead Wrasse that was 7.75 feet (2.29 m) long and weighed 420 lbs (190.5 kg).

Ecology

Adults are commonly found on steep coral reef slopes, channel slopes, and lagoon reefs in water 3 to 330 feet (1-100 m) deep. They are very opportunistic predators preying primarily on crustaceans, mollusks - particularly gastropods- fish, echinoderms. They are one of the few predators of toxic animals such as the sea hare Aplysia and boxfish Ostraciidae and have even been reported preying on crown-of-thorns starfish[1]. This species actively selects branching hard and soft corals and seagrasses at settlement. Juveniles tend to prefer a more cryptic existence in areas of dense branching corals, bushy macroalgae or seagrasses, while larger individuals and adults prefer to occupy limited home ranges in more open habitat on the edges of reefs, channels, and reef passes. The species is most often observed in solitary male-female pairs, or groups of two to seven individuals.

Reproduction

Individuals become sexually mature at 5 to 7 years and females are known to live for around 30 years whereas males live a slightly shorter 25 years. Humphead wrasse are protogynous hermaphrodites, with some members of the population becoming male at approximately 9 years old[2] The factors that control the timing of sex change are not yet known. Adults move to the down-current end of the reef and form local spawning aggregations they concentrate to spawn at certain times of the year.

Conservation

The humphead wrasse is long lived, but has a very slow breeding rate. Its numbers have declined due to a number of threats.

Threats include: 1) intensive and species-specific removal in the live reef food fish trade; 2) . In December 2003, Australia prohibited all take and possession of humphead wrasse, other than for limited educational purposes and public display. In Guangzhou province, southern mainland China, permits are required for the sale of this species; Indonesia allows fishing only for research, mariculture, and licensed artisanal fishing; the Maldives instituted an export ban in 1995; Papua New Guinea prohibits export of fish over 2 feet (65 cm) Total Length; and Niue has banned all fishing for this species.