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Halichoeres nigrescens

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES LABRIDAE

Scientific Name: Halichoeres nigrescens
Species Authority: (Bloch & Schneider, 1801)
Common Name/s:
English Bubblefin wrasse, Diamond wrasse, Dussumier's wrasse, Greenback wrasse, Kner's wrasse, White-button wrasse
Synonym/s:
Halichoeres dianthus Smith, 1947
Halichoeres dianthus Smith, 1947
Halichoeres dussumieri (Valenciennes, 1839)
Halichoeres dussumieri (Valenciennes, 1839)
Halichoeres kneri Bleeker, 1862
Halichoeres kneri Bleeker, 1862
Halichoeres leucostigma Fowler & Bean, 1928
Halichoeres leucostigma Fowler & Bean, 1928
Halichoeres nigriscens (Bloch & Schneider, 1801)
Halichoeres nigriscens (Bloch & Schneider, 1801)
Julis dussumieri Valenciennes, 1839
Julis dussumieri Valenciennes, 1839
Julis exornatus Richardson, 1846
Julis exornatus Richardson, 1846
Julis javanicus Bleeker, 1857
Julis javanicus Bleeker, 1857
Labrus baccatus Marion de Procé, 1822
Labrus baccatus Marion de Procé, 1822
Labrus mola Cuvier, 1829
Labrus mola Cuvier, 1829
Labrus nigrescens Bloch & Schneider, 1801
Labrus nigrescens Bloch & Schneider, 1801
Platyglossus amabilis De Vis, 1885
Platyglossus amabilis De Vis, 1885
Platyglossus dayi Steindachner, 1870
Platyglossus dayi Steindachner, 1870
Platyglossus dubius Steindachner, 1866
Platyglossus dubius Steindachner, 1866
Platyglossus immaculatus Macleay, 1878
Platyglossus immaculatus Macleay, 1878
Platyglossus maculatus Jatzow & Lenz, 1898
Platyglossus maculatus Jatzow & Lenz, 1898
Platyglossus ransonneti Steindachner, 1870
Platyglossus ransonneti Steindachner, 1870
Platyglossus roseus Day, 1888
Platyglossus roseus Day, 1888
Taxonomic Notes: Halochoeres kneri, H. exornatus, H. dussumieri, and H. javanicus are all synonyms of H. nigrescens. However, there are one or two new species that have been misidentified as H. exornatus (Allen in progress) and H. javanicus (R. Myers pers. comm.. 2008).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2010
Date Assessed: 2008-04-12
Assessor/s: Shea, S., Liu, M. & Sadovy, Y.
Reviewer/s: Craig, M.T. & Carpenter, K.E.
Justification:
This species is widespread in continental areas of the Indo-West Pacific, and is relatively common throughout its range, and can also be locally abundant. This species is taken by a wide range of fishing gears in multi-species fisheries, although it is unknown if this is a major threat to the global population. It is listed as Least Concern. However, more information is needed to determine potential impact of fisheries to this species.

Geographic Range [top]

Range Description: This species is found in the Indo-West-Pacific, from Taiwan, Philippines, Hainan Island, Singapore and Indonesia (Sadovy and Cornish 2000), and western Indian Ocean (Parenti and Randall 2000), from Durban, South Africa to the Gulf of Oman and southeast India, and the latitudinal range from Hong Kong to northwest Australia (Lieske and Myers 1994).
Countries:
Native:
Australia; Bahrain; Cambodia; China; India; Indonesia; Iran, Islamic Republic of; Iraq; Japan; Kenya; Kuwait; Madagascar; Malaysia; Mozambique; Myanmar; Oman; Pakistan; Papua New Guinea; Philippines; Qatar; Saudi Arabia; Singapore; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; United Arab Emirates; Viet Nam; Yemen
FAO Marine Fishing Areas:
Native:
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is relatively common throughout its range and can be locally abundant. It is common in Hong Kong waters. Sadovy and Cornish (2000) noted that it is the most abundant wrasse in shallow areas of corals and boulders in sheltered and exposed shores.

Visual surveys were carried out on the east coast of Zanzibar Island (6°6-13’S, 39°24-31’E), Tanzania, with a mean density found at 0.01 fish per 1000 m2 and mean biomass of 0.088 g per 1,000 m2 (Gullström et al. 2008).

In Thailand, it was rarely found in the 10 sampling stations at Ko Tao and the frequency of occurrence was less than 10 (Scaps 2006).

Despite the broad geographic distribution of this species, there is no information on the total numbers and there is very limited information on its local population stocks. Thus, the population status H. nigrescens cannot be inferred due to insufficient data.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This species inhabits shallow rubble and algae reef areas with little coral growth (Lieske and Myers 1994, Allen 2000, Kuiter 2002), and is found to depths of 20 m. The abundance was observed to decline with water temperature, as it was rarely seen under 16.5 °C in Hong Kong waters. Small individuals have been recorded to clean other fishes (Sadovy and Cornish 2000).

Although this species was reported to be a protogynous hermaphrodite (Sadovy and Cornish 2000), detailed gonadal histology is needed for further confirmation. Males are larger than females in body sizes. In Hong Kong, females become sexually mature at less than 8 cm TL and the smallest mature males are about 10 cm TL. Spawning activities have been observed around mid-day in shallow areas from April to July in Hong Kong waters (Sadovy and Cornish 2000). Histology study showed that it becomes mature from May to September and has a spawning season that lasts approximately three months. It was also found that sperm in the early developing stage aggregate in lobules with tails oriented towards the centre and such distinctive feature disappeared when gonads become ripe close to spawning (Valerie 2002).

Males are light greenish dorsally and pale ventrally with six to seven interconnected reddish brown bars (Sadovy and Cornish 2000). It has approximately 13 pectoral fin rays and yellow corners to caudal fin (Allen 200). Black and yellow spots are present in the dorsal fin. Juveniles have a black spot on soft dorsal fins and there is a prominent dark spot at upper pectoral fin base in both sexes. The dorsal fin spot has been observed to flash occasionally (Sadovy and Cornish 2000).
Systems: Marine

Threats [top]

Major Threat(s): This species is caught as bycatch in a number of different fisheries. It is vulnerable to a wide range of fishing gears. It is not known if the pressure from fishing within the distribution of this species is considered to be a major threat.

Conservation Actions [top]

Conservation Actions: There are no specific conservation measures in place for this species. Its distribution overlaps several marine protected areas within its range.

In Hong Kong, this species is found in Hoi Ha Wan Marine Park (Cornish 2000, Ku et al. 2007), Yan Chau Tong Marine Park and Tung Ping Chau Marine Park (Cornish 2000). It has also been recorded from the Mu Ko Surin National Park, Thailand (Comley et al. undated).

However, marine protected areas do not always imply the presence of no-take zones. For example, licensed fishing and specimen collecting are allowed in the Hoi Ha Wan Marine Park, Yan Chau Tong Marine Park and Tung Ping Chau Marine Park (AFCD 2008). This species was also observed in the Cape d’ Aguilar Marine Reserve, Hong Kong (Cornish 2000) where fishing is prohibited for more than 10 years.

It is recommended that research be conducted to determine possible indicators of localized or regional declines due to current fishing activities within this species range.
Citation: Shea, S., Liu, M. & Sadovy, Y. 2010. Halichoeres nigrescens. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 24 April 2014.
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