Humphead wrasse  (Cheilinus undulatus)

The humphead wrasse is classified as Endangered (EN) on the IUCN Red List (1), and listed on Appendix II of CITES (3).

The humphead or Napoleon wrasse (Cheilinus undulatus) is one of the largest reef fishes in the world and is the largest member of the wrasse family (Labridae) (4). The enormous size of adult fish is made even more imposing by the prominent hump that develops on their forehead, from which they earn their common name (2). Mature adults also have thick lips; juveniles can be identified by their pale greenish colour and two black lines running behind the eye (2).

The humphead wrasse is found throughout the Indo-Pacific Oceans, from the Red Sea and the coast of east Africa to the central Pacific, south from Japan to New Caledonia (4).

Associated with coral reefs; adult humphead wrasse inhabit the outer reef slopes and drop-offs, showing fidelity for particular sites, whilst juveniles are usually found amongst thickets of living staghorn coral (Acropora spp.) (4).

Humphead wrasses are extremely long-lived, known to survive for at least 30 years, and taking around five to seven years to reach sexual maturity (4). Adults are usually solitary, spending the day roaming the reef and returning to particular caves or ledges to rest at night (2). Very little is known about these fish; adult females are able to change sex but the triggers for this development are not known (4). Pairs spawn together as part of a larger mating group that may consist of over 100 individuals. The planktonic eggs are released into the water and once the larvae have hatched they will settle out on the substrate (4).

Using their tough teeth, these fish are able to consume hard-shelled species such as molluscs, echinoderms and crustaceans (4). They are one of the few predators of species that destroy coral reefs, such as the infamous crown of thorns starfish (Acanthaster planci) (2).

Although the humphead wrasse has a widespread distribution, it has never been common in its range and recent reports have revealed a worrying decline in numbers. Its life history characteristics make this species extremely vulnerable to exploitation and the population can only sustain light levels of fishing (4). Traditionally, the flesh of this fish has been highly prized and more recently this species has become one of the most highly sought species of the Live Reef Food Fish Trade (LRFFT), a luxury food industry that has undergone an increase in popularity in many eastern Asian countries (4). Humphead wrasse can fetch up to US $100 per kilogram at retail in Hong Kong (4), and as their numbers dwindle the rarity of the species is likely to increase the price (4). Cyanide is typically used to catch fish for this trade because live fish are difficult to take any other way; a practice that devastates coral reefs (4).

Little is known of the biology and distribution of the humphead wrasse and more data are urgently needed to understand the scale of the threats faced by current populations, and to implement effective conservation programmes (4). The World Conservation Union's (IUCN) Groupers and Wrasses Specialist Group is working to collect this all-important data and to raise awareness of the issues involved throughout the region (4). The species is partially protected in areas of Australia, the Philippines, the Maldives and Palau and was proposed for inclusion in Appendix II of the Convention on International Trade in Endangered Species (CITES) in November 2002 (4). Trade restrictions are particularly important, as this species cannot be hatchery reared and all individuals in trade come from wild populations (5).

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

For further information: 

• Humphead Wrasses Awareness Campaign:
  http://www.iucn.org/about/work/programmes/species/about_ssc/specialist_groups/directory_specialist_groups/directory_sg_fishes/groupers_wrasses_sg/