Almost nothing is known of the biology and ecology of the Asian sheepshead wrasse, other than that it feeds on shellfish and crustaceans. Additionally, spawning behaviour has been observed in large aquaria, in which the strongest male drove away all other males before rising rapidly to the surface with a single female, where spawning occurred (1). Wrasses, especially the larger species, generally live long lives, are slow to reach sexual maturation and produce millions of tiny eggs in reproduction (3). Many species, including the related California sheepshead wrasse (Semicossyphus pulcher
), change sex from female to male several years after female maturation, a phenomenon known as sequential hermaphroditism, or protogyny (1) (3).
One of the largest wrasses, the Asian sheepshead wrasse is an extraordinary pinkish-grey fish with large, swelling-like protrusions on the 'forehead' and 'chin'. Like its close relative, the California sheepshead wrasse (Semicossyphus pulcher
), the juvenile is starkly different from the adult, being a vivid yellowish-orange with a white stripe from the eye to the tail, black patches on the fins and tail, and lacking the bulbous face protrusions of the adults, for which the species earns its common name (2).
One of the largest wrasses.
Recorded from the main islands of Japan, the Korean Penninsula and South China Sea including China (Masuda et al
. 1984) but not Taiwan (The Fish Database of Taiwan
). Extent of distribution along the coast of mainland China is not clear but it is known from islands close to Hong Kong (Sadovy and Cornish 2000).
In Japan S. reticulatus
inhabits cooler waters and is found in the Japan Sea and Seto Inland Sea (Masuda et al
. 1975). Reported occurrence in the Ogasawara Islands is in doubt (Randall et al
. 1997). Given that this is a cold water species and is rare in subtropical Hong Kong, the latter probably represents the southern limit for the species along the coast of mainland China.
Western Pacific: southern Japan, South Korea, and the South China Sea.
Recorded in the Western Pacific from the main islands of Japan, the Korean Peninsula and the South China Sea (1) (2).
Maximum size: 1000 mm TL
100.0 cm TL (male/unsexed; (Ref. 559)); max. published weight: 14.7 kg (Ref. 40637)
IGFA 2001 Database of IGFA angling records until 2001. IGFA, Fort Lauderdale, USA. (Ref. 40637)
Masuda, H., K. Amaoka, C. Araga, T. Uyeno and T. Yoshino 1984 The fishes of the Japanese Archipelago. Vol. 1. Tokai University Press, Tokyo, Japan. 437 p. (text). (Ref. 559)
Habitat and Ecology
Habitat and Ecology
Inhabits rocky reefs and feeds on shellfish and crustaceans (Masuda et al. 1975). Spawning in large aquaria has been observed; the strongest male drove away all other males and then rose rapidly to the surface with a single female where spawning occurred (Nishiguchi and Okuno 1965). Systems
This is a cold-water to subtropical species that inhabits rocky reefs (1) (2).
Lives in rocky coastal regions (Ref. 9137).
IUCN Red List Assessment
Red List Category Year Assessed
Data Deficient Red List Criteria Version
Cornish, A. (Grouper & Wrasse Specialist Group) Reviewer/s
Sadovy, Y. & Nakazono, A. (Grouper & Wrasse Red List Authority) Contributor/s Justification
Remarkably little information is available about Semicossyphus reticulatus
despite its size and the fact that it is a large and conspicuous wrasse and a valued food fish. The Japan Game Fish Association record is 14.7 kg and the species can attain 100 cm in total length (Masuda et. al
. 1975). Japan The only information on possible changes in abundance over time is that "occurrence of juveniles at the northern coast of Kyushu have not changed for many years" (A. Nakazono pers. comm. 2003). The species is not preferred in Japan and only consumed locally (i.e., not exported) (Dr. Shigeta and Dr. A. Nakazono pers. comms.). It is not particularly common. There are no UVC data (A. Nakazono, pers. comm). A student (Okamoto communicating to A. Nakazono) regularly surveying fishing ports in eastern Kyushu did not see any individuals landed but did catch two (ca. 33 cm TL) after putting out gill nets. There were no landings records obtainable and the species is not a preferred eating fish because of its soft tissue. The use of the attractive juveniles by fish hobbyists is not known (A. Nakazono pers. comm.). An area of concern for this species, that of reproductive biology, is suggested from one of only two other congeners, Semicossyphus pulcher
which occurs off California and has been much better studied. S. pulcher
is a similar size to S. reticulatus
, reaching a maximum length of 91 cm (FishBase
) and also inhabits cool waters. It is protogynous with females reaching sexual maturity at 3–6 years (depending on location) and sexual transformation from female to male taking place several years later (Cowen 1990). Sex-changing fish can be particularly vulnerable to fishing where fishing targets a narrow range of sizes as this may target the sexes differentially resulting in populations with skewed sex-ratios. Semicossyphus reticulatus
is assessed as Data Deficient ,as crucial information on population size and biology is not available. In order to assess this species in future the following information is required: 1. Basic information on relative abundance (CPUE or landings) from mainland China and southern Korea and on sizes fished. 2. Fisheries and/or visual census data over time that can be used to infer changes in population size and threats from fishing in each of mainland China, Japan and the Korean peninsula. 3. Basic information on the ways this species is targeted in each of mainland China, Japan and the Korean peninsula. 4. Information on age and size of sexual maturity and whether or not the species changes sex. Given the large size of the species and its probably intrinsic vulnerability, information needs to be collected or sourced for it and a reassessment carried out as soon as possible.
Classified as Data Deficient (DD) on the IUCN Red List 2006 (1).
Almost nothing is known about the abundance of the Asian sheepshead wrasse. It is "commonly found" in the Japan Sea and Seto Inland Sea (Masuda et al. 1975) and is rare in the vicinity of Hong Kong (Sadovy and Cornish 2000). Population Trend
Overfishing is likely to be the major threat to this species. The extent of this threat is not known, primarily as this species only appears to be targeted as part of a mixed reef fishery and, therefore, little research has been done on this species individually.
Although very little is known about the Asian sheepshead wrasse's population status or the threats facing it, it is thought to be intrinsically vulnerable to overfishing due to its biology (1). The life history characteristics of many wrasses make them particularly vulnerable to fishing because, being long-lived with late onset of maturity and low rates of population growth, they are typically slow to recover from exploitation. Furthermore, sex-changing fish are at risk where fishing targets the largest fish (mostly males), as this can lead to strongly female-biased sex ratios, potentially compromising reproduction through too few males (3).
Data deficient (DD) , IUCN Grouper and Wrasse Specialist Group
There are not known to be any fishing restrictions, nor no-take marine reserves within the range of this species. However, at some places in the Japan Sea, the spawning adult fish are protected by local divers to attract tourist divers (A. Nakazono, pers. comm., 2003).
There are no known fishing restrictions within the range of this species, nor marine reserves where fishing is prohibited. However, at some regions in the Japan Sea, spawning adult fish are protected by local divers who wish to attract tourist divers. Crucial research and information is required on the population size and biology of this species before it can be properly assessed by the IUCN (1).