Threatened fishes of the world: Cheilinus undulatus Rüppell, 1835 (Labridae)

Abstract

Common names: Maori, Napoleon or humphead wrasse (English), so-mei (Hong Kong, southern China and Taiwan) and numerous other names throughout the Indo-West Pacific region. Conservation status: Listed as ‘vulnerable’ in the IUCN 1996 Red Data Book because of severe declines in sizes and numbers in SE Asia attributed to heavy exploitation for the live reef fish trade (LRFT). Identification: A distinctive species and among the largest of all reef fishes. Adults are blue/green with large scales and a yellow posterior margin to the caudal fin; small individuals are pale with black markings. Can attain a TL of 250 cm and Wt of 191 kg; D IX, 10; A III, 8; P 12; ll 14–16 + 7–8; GR 6–7 + 13–14 = 19–21; depth 2.2–2.7, increasing with age. Large adults develop a prominent bulbous hump on the forehead and thick, fleshy lips (Myers 1999). Drawing from FAO Species Identification Sheets used by permission. Distribution: Tropical and sub-tropical Indo-West Pacific (Myers 1999). Abundance: Observed frequently as solitary individuals, in male–female pairs (i.e. Myers 1999) or in social groups consisting of a single male, 2–7 smaller adults, and several juveniles. This species is uncommon wherever it occurs (Y. Sadovy, M. Kulbicki, P. Labrosse, Y. Letourneur, P. Lokani & T.J. Donaldson unpublished). Habitat and ecology: Occurs along steep outer reef slopes, channel slopes, and lagoon reef slopes at depths of 2–60 m. Adults observed hovering off coral reef slopes and walls, cliff walls, or in boulder-rich habitats, frequently seeking shelter in caves or crevices, especially at night, while juveniles have been observed in coral thickets within lagoons or on deeper reef flats (Myers 1999). This species feeds primarily upon molluscs, but its diet includes crustaceans, heavy-shelled gastropods, sea urchins, brittle stars, starfishes (including crown-of-thorns starfish, Acanthaster planci), and fishes. Because its diet includes fishes, it may be ciguatoxic in some areas (Randall et al. 1978, Myers 1999). Reproduction: Forms small mating groups or spawning aggregations (Donaldson 1995, Sadovy et al. unpublished). Spawning is paired with production of pelagic eggs. The smallest size at sexual maturation is between 40–60 cm TL and some males develop directly from juveniles; diandric protogyny, found in many other family members, has been confirmed for this species (Sadovy et al. unpublished). Threats: These include: (1) intense and species-specific (i.e. selective) fishing for the LRFT with juveniles the predominant size range marketed in Hong Kong (Lee & Sadovy 1998); (2) capture by destructive fishing, especially cyanide; (3) spearfishing at night with SCUBA or hookah gear; (4) illegal fishing; (5) poor or no management at most localities; (6) continued trade because its high value increases with rarity, thus encouraging continued fishing even at low population numbers. Conservation action: This species is, or has been, fully or partly (i.e. for certain size classes) regulated, protected or banned from export in Australia, Indonesia, Maldives, Philippines (Palawan), Palau, and the Solomon Islands. Conservation recommendations: (1) Implement a moratorium on fishing for export. (2) Fund research on Cheilinus undulatus ecology and behavior, and especially population structure. (3) Create marine reserves that incorporate key habitat, such as spawning areas. (4) Educate resource managers, consumers and the general public on the importance of conserving this species. Remarks: The large size attained by this species suggests that it may be long-lived, and if typical of reef fishes of similar size and biology, it is expected to have low replacement rates and to be particularly vulnerable to fishing pressure. There is little chance that culturing will remove pressure on wild-caught individuals in the near future because it is difficult to culture. This species’ importance to divers means that the humphead wrasse does much to promote conservation interest in reef areas and is of high tourism value. This is Contribution No. 447 of the University of Guam Marine Laboratory.