Fish
Humphead Wrasse
Cheilinus undulatus · also called humphead wrasse, Napoleon wrasse, Māori wrasse
The humphead wrasse is a giant of the coral reef — a two-metre, big-lipped, bulge-headed fish that cruises the outer reef slope crunching sea urchins and toxic pufferfish that nothing else will touch. It is also one of the most valuable fish in Asia’s live-seafood trade, which has more than halved its numbers.
Overview
Humphead wrasse live on Indo-Pacific coral reefs, from the Red Sea to the central Pacific, with adults favouring steep outer reef slopes and channels. They are large, long-lived (30-plus years), and naturally never abundant — a healthy reef holds only a few. Adult males have a pronounced forehead hump (the “Napoleon” name, after a bicorne hat) and thick fleshy lips, plus maze-like markings around the eyes (the “Māori wrasse” name).
A specialist diet
Its powerful jaws and crushing throat teeth open a menu closed to other fish: hard-shelled molluscs and crabs, sea urchins, and chemically defended prey — boxfish, pufferfish (tetrodotoxin), sea hares, and the venomous crown-of-thorns starfish. By eating crown-of-thorns and urchins, it helps keep reefs in balance.
Sex change
The humphead wrasse is a protogynous hermaphrodite — it matures as a female, and some large individuals later become male. Fishing that removes the biggest fish removes the males, and a population can be left unable to breed.
Why it is Endangered
Slow-growing, late-maturing, naturally rare, site-attached, bold around divers, and sex-changing — then targeted as one of the most valuable fish in the Hong Kong / China live reef food fish trade, sometimes caught with reef-poisoning cyanide. Populations have fallen more than 50% in three generations.
Status
Endangered. Listed on CITES Appendix II since 2004, with additional protection, size limits, or export bans in several range countries and within marine reserves. Enforcement across the Indo-Pacific and demand reduction in Asia are the main tools.
Humphead Wrasse: common questions
How big does a humphead wrasse get, and why is it called the Napoleon wrasse?
Large males reach about 2 metres and 180 to 190 kilograms, making the humphead wrasse one of the biggest bony fish found on coral reefs, rivalled among reef fish only by the giant grouper. The alternative name "Napoleon wrasse" (or Napoleonfish) comes from the shape of the pronounced bony hump on an adult male's forehead, which was thought to resemble the bicorne hat worn by Napoleon Bonaparte. "Māori wrasse" refers to the intricate maze-like markings around its eyes, likened to Māori facial tattoos (moko).
What does the humphead wrasse eat that other fish won't?
Its powerful jaws and crushing throat teeth let it exploit a menu that is largely closed to other reef fish. It eats hard-shelled molluscs and crabs, sea urchins, and, notably, prey that is chemically or physically defended — including the boxfish and pufferfish (which carry tetrodotoxin), the sea hare, and the crown-of-thorns starfish, whose venomous spines deter almost everything else. By preying on crown-of-thorns, which strip living coral, and on urchins that overgraze, the humphead wrasse helps keep reefs in balance, so its loss has knock-on effects.
Why is the humphead wrasse endangered?
It has a set of traits that make it exceptionally vulnerable to fishing, and then it is fished hard. It grows slowly, matures late (around 5 to 7 years), is naturally uncommon even on healthy reefs, is site-attached and predictable, is large and unafraid of divers, and changes sex so that removing the biggest fish removes the males. On top of this, it is one of the most valuable fish in the live reef food fish trade centred on Hong Kong and mainland China, where large individuals command very high prices at restaurants. Fishers target it with hook and line and, destructively, with cyanide, which stuns the fish for capture but poisons the surrounding coral. Populations have more than halved in three generations, and it is now rare or absent on many reefs.
Is it protected?
Yes, increasingly. The humphead wrasse was listed on CITES Appendix II in 2004, meaning international trade must be regulated and shown to be sustainable, and a number of range countries have introduced full protection, size limits, or export bans (including Australia, the Maldives, and Indonesia in various forms). It is also protected within many marine reserves. Enforcement across the vast Indo-Pacific and against a lucrative, partly illegal trade remains the central challenge, and demand-reduction efforts in Hong Kong and China are part of the response.