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