We are fortunate enough to encounter Napolean Wrasse in both our locations – Similan Islands and Komodo National Park. We thought we would share a bit more about these incredible creatures 🙂
Napoleon Wrasses are also known as napoleon fish, maori wrasse, or “so mei” (in Cantonese), “mameng” (in Filipno) or is simply referred to as the napoleon fish.
It is one of the largest reef fishes in the world and is the largest member of the wrasse family.
The napoleon wrasse is instantly recognisable by its size, colour and shape. They can grow up to 230 cm and weigh 190 kg. They have thick fleshy lips and a hump over the head that is similar to a napoleon hat. The hump becomes more pronounced with age.
Colours vary with age and sex. Males range from a bright electric blue to green, a or purplish blue. Mature males develop a black stripe along the sides, blue spots on their body scales, and blue scribbles on the head. Juveniles can be identified by their pale greenish colour and 2 black lines running behind the eye. Females, both old and young, are red-orange on the upper parts of their bodies and red-orange to white below.
Maori wrasse, like all other wrasses, have protrusible mouths, with separate jaw teeth that jut outward.
Napoleon wrasses are hermaphrodites, with some members of the population becoming male at approximately 9 years old. The females tend to live longer on average, about some 30 years, while the males only last about 25 years.
Napoleon wrasses spend most of their time feeding during the day. Adults are usually solitary, spending the day roaming the reef and returning to particular caves or ledges to rest at night.
In some areas they are very inquisitive, but in others where they are hunted they are very shy.
Napoleon wrasses are carnivorous and eat during the day. They can be seen feasting on shellfish, other fish, sea stars, gastropods- fish, echinoderms, sea urchins and crabs, crushing the shells to get at the animal within. Napoleon wrasses also crush large chunks of dead coral rubble with peg-like teeth to feed on the burrowing mussels and worms.
Napoleon wrasses are one of the few predators of toxic animals such as sea hares, boxfish and crown-of-thorns starfish, and are therefore an important part of the marine food chain in maintaining a balanced and healthy coral reef.
Individuals become sexually mature at 5 to 7 years and 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.
Adults are commonly found on steep coral reef slopes, channel slopes, and lagoon reefs in waters 1–100 m deep, choosing branching hard and soft corals and seagrasses as their settlements. Juveniles tend to hide away in areas of dense branching corals, bushy macroalgae or seagrasses, however some larger adults can be found on the edges of reefs, channels, and reef passes. Napoleon wrasses are often seen in solitary male-female pairs, or in groups of two to seven individuals.
In thailand we most commonly find them at Christmas Point and Sharkfin Reef. In Komodo they are found at most sites with encrusting hard coral…about 30% of all sites and are seen on every dive trip.
Napolean Wrasse Conservation
The napoleon wrasse is long lived, has a late maturation age and a very slow breeding rate making it highly vulnerable to over exploitation.
Its numbers have declined due to a number of threats. Including; spearfishing, other destructive fishing techniques, including sodium cyanide and dynamite, habitat loss and degradation, juveniles being taken from the wild and raised or “cultured” in floating net cages until they are mature enough to be sold to supply the demands of the marine aquarium trade. There is also a high demand for the napoleon wrasse’s lips, a single pair today has a market value of 400 dollars.
Traditionally, the flesh of this fish has been highly prized, and more recently it has become one of the most highly sought species in the luxury food industry that has undergone an increase in popularity in many eastern Asian countries. The species cannot be artificially cultured in hatcheries so there is no option to relieve fishing pressure.
Concerns for the future of the napoleon wrasse are so high that it is the only reef fish protected by species name across a range of countries, it has also been red listed by the International Union for Conservation of Nature and Natural Resources, and is also listed for protection on the Convention on International Trade in Endangered Species (CITES).
The napoleon wrasse is of absolutely no threat to the scuba divers. This fish can be seen mostly during the day when they swim around the edges of the coral reef and remain very active. When darkness falls they tend to retire to their caves or large reef structures and rest.
It is also one of the most impressive fish to come across when diving. Due to its size it is an awe-inspiring, imposing presence, and its curious and intelligent looking eyes will watch your every move carefully. Napoleon wrasses are mostly loved by divers because they are extremely curious, often very assertive and occasionally enjoy a little tactile interaction. The Wrasse are known to get attached to divers and can often recognize their favorite diver and approach to be stroked, often nudging the diver like a dog does when it wants to be petted!