Species Details

Details of Hump-headed Wrasse will be displayed below

Hump-headed Wrasse   

Common Name: Blue-tooth Groper, Double-headed Maori Wrasse, Double-headed Parrot-fish, Giant Maori Wrasse, Giant Wrasse, Hump-headed Maori Wrasse, Maori Wrasse, Napoleon Maori-wrasse, Napoleon Wrasse
Scientific Name: Cheilinus undulatus
Local Name: Maahulhunbu Landaa
Dhivehi Name: މާހުޅުނބު ލަނޑާ
Animalia  (Kingdom)
Chordata  (Plylum)
Perciformes  (Order)
Labridae  (Family)
Cheilinus   (Genus)

Hump-headed Wrasse's description

The humphead wrasse is an enormous coral reef fish—growing over six feet long—with a prominent bulge on its forehead.

Distinctive Features:

One of the largest reef fishes in the world, the humphead wrasse is made even more imposing by the presence of a prominent hump located on the forehead from which it earns its various common names. This hump forms above the eyes, becomes even more prominent as the fish ages. Adults have relatively deep bodies, thick fleshy lips, and a rounded caudal fin.

Coloration:

Humphead wrasses have distinct coloration with males ranging from a bright electric blue to green, purplish-blue or dull blue-green. Females are red-orange above to a pale or white ventral surface. As in numerous species of wrasses, some of the female humphead wrasses reverse sex to become males while other fish may start life as males. In the larger males, the hump on the head becomes more prominent and takes on a brilliant blue coloration. In addition, the squiggly patterns on the face become more intense in color. Consequently, it is these markings that are said to resemble facial tattoos of the Maoris, resulting in the common name Maori wrasse.

Dentition:

These large reef fish has tough teeth fused into a parrot-like beak, enabling them to consume hard-shelled species including mollusks, echinoderms and crustaceans. The pharyngeal teeth, a second set of dentition located inside the fish’s throat, enable the fish to crush prey items. Divers who observe a school of humphead wrasses feeing on a reef have been known to hear the noise and see the clouds of dust from the demolition of hard corals by this species.

Size, Age, and Growth:

The maximum reported length of the humphead wrasse is 90 inches (229 cm) total length (TL), however it is more commonly observed at lengths of 24 inches (60.0 cm) TL. Females rarely exceed about 3 feet (1 m) in length. The maximum published weight is pounds 421 pounds (191.0 kg) and maximum reported age is 32 years. It is believed that this species reaches sexual maturity at 5-7 years of age and lengths of at least 16-24 inches (40-60 cm) TL; and are extremely long-lived to at least 30 years.

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.

Hump-headed Wrasse's facts

DO you know?

  • The species name 'undulatus' comes from the Latin for 'waved' or 'wavy'.
  • It is the largest species in the family Labridae, growing to 2.3 m in length and 190 kg.
  • The humphead wrasses are very important to coral reef health. They eat crown-of-thorn starfish and therefore keep populations of this damaging coral reef predator in check.

Hump-headed Wrasse's Behavior & Ecology

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.

Adults are usually solitary, spending the day roaming the reef and returning to particular caves or ledges to rest at night. Adult females are able to change sex but the triggers for this development are not known.

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

Hump-headed Wrasse's Feeding

The Humphead Maori Wrasse feeds on molluscs, fishes, sea urchins, crustaceans and other invertebrates. Prey items comprising the humpback wrasse’s diet include mollusks, sea urchins, crustaceans, and fishes. Some of these prey items are toxic such as sea hares, boxfishes, and crown-of-thorns starfish. It is also known to feed on sharp-fanged moray eels.

Hump-headed Wrasse's Reproduction

The humpback wrasse is a protogynous hermaphrodite, with some females becoming male at approximately 9 years of age. Factors controlling this sex change timing are as of yet undetermined. Spawning occurs at certain times of the year with adults forming spawning aggregations at the down-current end of the reef. Pairs spawn together as a part of the aggregation which may number up to 100 individuals.

Hump-headed Wrasse's Conservation

Although this species is long-lived, it has a very low reproductive rate resulting in a decline in numbers due to a number of threats. These threats include the live reef food fish trade, spearfishing, destructive fishing techniques (cyanide/dynamite), habitat loss and degredation, marine aquarium trade, and unregulated fisheries. In response to declining populations of the humphead wrasse, some countries have began to take action. In 2003, Australia prohibited the take and possession of this species other than for some educational uses and public display. Indonesia currently allows fishing of the humphead wrasse for research, mariculture, and limited artisanal fishing. Other countries including the Philippines, Maldives (protected since 24th June 1995), and Palau have enacted some protective regulations as well. The U.S. National Marine Fisheries Service considers it a species of concern although it is data deficient to be listed under the Endangered Species Act.

Formerly listed as “Vulnerable” by the World Conservation Union (IUCN), the humphead wrasse has since been upgraded to “Endangered” status. The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species. The IUCN’s Grouper and Wrasse Species Specialist Group is collecting data and raising awareness of this species. The humphead wrasse is also listed in Appendix II of CITES.

Hump-headed Wrasse's Relationship with Humans

Traditionally the flesh of this fish has been highly regarded for human consumption. Eating this fish has resulted in cases of ciguatera poisoning. The humphead wrasse is a species commonly exhibited in public aquarium facilities and is considered of importance to eco-tourism in areas frequented by divers. This has resulted in the promotion of conservation due to the high tourism value of protecting this species.

Hump-headed Wrasse habitat

In one study, small post-settlement humphead wrasses were found in a species of seagrass (Enhalys acoroides), four species of hard coral (three Acropora spp. and Porites cylindricus), and in the soft coral Sarcophyton sp. (branching form; M.A. Tupper, pers. comm.). After settlement, juveniles and adults live associated with reef or near-reef habitats of seagrass beds and mangrove areas, with juveniles typically inshore and the largest individuals found in deeper waters of outer reefs or lagoons (Myers 1999). Juveniles of 3–20 cm TL, and larger, occur in coral-rich areas of lagoon reefs, particularly among live thickets of staghorn, Acropora spp. corals, in seagrass beds, murky outer river areas with patch reefs, shallow sandy areas adjacent to coral reef lagoons, and mangrove and seagrass areas inshore (Randall 1955, Randallet al. 1978, Myers 1999, J.H. Choat, pers. comm.). Recruitment patterns may vary considerably between years (M.A. Tupper, unpublished data). Adults are more common offshore than inshore, their presumed preferred habitat being steep outer reef slopes, reef drop-offs, reef tops, channel slopes, reef passes, and lagoon reefs to at least 100 m. They are usually found in association with well-developed coral reefs (Vivien 1973, Randall et all. 1978, Winterbottom et al. 1989, Allen and Swainston 1992, Sluka 2000). Typically they are solitary or paired, but have also been noted in groups of 3–7 individuals (Donaldson 1995). They appear to be somewhat sedentary in that the same individuals, indentifiable by distinct natural markings, may be seen along the same stretch of reef for extended periods. Indeed, many commercial dive sites have their ‘resident’ Humphead Wrasse, a favoured species for divers. Natural densities are evidently never high, even in presumed preferred habitats. For example, in unfished or lightly fished areas, densities may range from two to rarely more than 10–20 individuals per 10,000 m² of suitable reef. In fished areas, however, densities are typically lower by tenfold or more, and in some places fish no longer appear to be present.

Accounts of reproductive activity in the field reveal that, depending on location, this species spawns between several and all months of the year, in small or large groupings, that spawning coincides with certain phases of the tidal cycle, and that groups of spawning fish can form daily, at a range of different reef types. Spawning areas and aggregated adults have been noted regularly along specific sections of reef, sometimes associated with no obvious topographical features, sometimes close to the shelf edge on outer reefs, or adjacent to exposed reef passes near fairly steep drop-offs, or on mid-shelf (unspecified) reefs (P.L. Colin, J.H. Choat, R. Hamilton, S. Oakley, pers. comms.). The species is evidently a daily spawner that probably does not migrate far to its spawning site(s), spawning for extended periods each year, i.e., a ‘resident’ spawner (Domeier and Colin 1997, P.L. Colin, pers. comm.): groups of up to 150 fish were observed in Palau along the shelf edge in a loose aggregation.

Probable spawning aggregations have also been noted on Australia’s Great Barrier Reef (GBR), Fiji, New Caledonia, and in the Solomon Islands. Although spawning was not always observed, aggregated fish were ripe, or exhibiting behaviour likely associated with spawning. On the GBR, aggregations of up to 10 large males and 20–50 smaller fish (35–95 cm TL) were noted (J.H. Choat, pers. comm.). GBR aggregations from the Ribbon Reefs and north of Jewell Reef, once noted to include hundreds of fish, are no longer known at the same sites (Johannes and Squire 1988, L. Squire, pers. comm.).

The longevity of this species is up to at least 32 years, with females outliving the males (the oldest female recorded was 32 years), and sexual maturity is reached at about eight years of age (Choat in Pogonosky et al. 2002). Histological studies show that sexual maturation is reached at a size of between 40 cm and 60 cm total length (Sadovy, unpublished data). This species is thought to be a protogynous hermaphrodite, with sex reversal occurring at about 15 years of age (Choat in Pogonosky et al. 2002). At a total length of approximately 111 cm (Lau and Li 2000). Males grow very rapidly (Choat in Pogonosky et al. 2002).

It feeds on a variety of molluscs, fishes, sea urchins, crustaceans and other invertebrates (Randall et al. 1997).

Hump-headed Wrasse threats

Threats include:

1) Intensive and species-specific removal for the live reef food fish export trade of a naturally uncommon and vulnerable species;
2) Readily accessible to spearfishing at night with SCUBA or hookah (i.e., compressed air) gear, and easy to catch with cyanide, or other poisons such as Derris trifoliata, due to predictable adult habitat and shallow depth range;
3) Lack of coordinated, consistent national and regional management largely due to limited management capacity and the sometime secretive nature of traders – in particular there is no relevant regional fishery management authority to address problems with this species;
4) Selective fishing, in particular the intensive take of juveniles for direct export sale and for grow-out (also referred to as ‘culture’ – the species cannot be hatchery reared; and
5) Illegal, unregulated, or unreported (IUU) fisheries (Donaldson and Sadovy 2001).

In addition, the species’ essential coral reef habitat is seriously threatened by human activity throughout the Indo-Pacific region. Destructive fishing practices, such as sodium cyanide use which stuns animals for capture and incidentally kills living coral, have been well documented and are spreading in the Indo-Pacific region (Barber and Pratt 1998, Burke et al. 2002, Bryant et al. 1998, Johannes and Riepen 1995). Despite its prohibition in many countries (including major exporters such as the Philippines and Indonesia), cyanide is still the preferred method for capturing certain live reef fish for international trade in some areas (Burke et al. 2002, Bryant et al. 1998, Johannes and Riepen 1995, Barber and Pratt 1998). Indeed, larger Humphead Wrasse are difficult to catch any other way, other than by night-time capture. When cyanide is applied, the fish often retreats into a crevice and becomes increasingly lethargic as the toxin reduces its ability to take up oxygen. Divers may break away the living coral to get access to the hiding area, and remove the fish to clean water where it will often recover for shipment or holding in net pens.

The most serious threat to this species is overfishing for the live fish export trade. They are mainly taken live for food – only rarely for the aquarium trade as far as can be determined. This species is long-lived and naturally uncommon, and if it is similar to other reef fishes of similar size and biology (e.g., sequential hermaphroditism; aggregation-spawner) it is expected to have low rates of replacement and therefore be particularly vulnerable to fishing pressure (Donaldson and Sadovy 2001). Moreover, being one of the largest of all reef fishes, they have few natural predators which means that fishing mortality may rapidly exceed natural mortality, possibly accounting for the rapid declines noted once fishing intensifies.

Although data are not available from throughout its range, wherever there are significant exports and no effective controls, fish numbers have declined substantially within a decade or less and exploitation rates are expected to continue, or more likely, intensify. There are few refuges for this species since live reef fish carriers have access to all reefs where it occurs and it does not extend into very deep water, probably little more than 60 m. Adults only occur in reasonable numbers where the fishery is effectively managed or where they occur in marine protected areas.

There has been speculation that Humphead Wrasse, and other reef fishes, can be cultured or "farmed" to meet international demand. However, it appears that the use of cultured fish may actually pose a threat to wild populations in certain circumstances since it does not involve hatchery production (not yet possible for this species and unlikely to be possible at commercial levels for many years according to experienced aquarist M.A. Rimmer, pers. comm.) but the grow-out of wild sourced juveniles.

Hump-headed Wrasse's status