|Scientific Name:||Variola louti (Forsskål, 1775)|
Epinephelus louti (Forsskål, 1775)
Labrus punctulatus Lacepede, 1801
Perca louti Forsskål, 1775
Serranus cernipedis Miranda Ribeiro, 1913
Serranus flavimarginatus Ruppell, 1830
Serranus longipinna Swainson, 1839
Serranus louti (Forsskål, 1775)
Serranus luti Valenciennes, 1828
Serranus melanotaenia (Bleeker, 1857)
Serranus phaenistomus Swainson, 1839
Serranus punctulatus (Lacepede, 1801)
Serranus roseus Valenciennes, 1828
Variola longipinna Swainson, 1839
Variola louti (Forsskål, 1775)
Variola melanotaenia Bleeker, 1857
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Choat, J.H., Craig, M. & Ferreira, B.|
|Reviewer(s):||Sadovy, Y. & Moss, K. (Grouper and Wrasse Red List Authority)|
Variola louti is assessed as a species of Least Concern since it has a very widespread distribution and is locally abundant in many parts of its range. Although it has shown sharp declines in regional fisheries (up to 70% decline over 20 years), its large range may provide a buffer to overfishing.
Variola louti occurs throughout the tropical Indo-Pacific region from the Red Sea to the Pitcairn Islands of eastern Oceania. It is found along the east coast of Africa south to Durban (South Africa) and along the western coast of Australia to Shark Bay. This common and widely distributed grouper is known from most of the tropical islands of the Indian and west central Pacific oceans. In the western Pacific it ranges from Japan (southern Honshu) to New South Wales (Australia). It has not been found in the Persian Gulf or the Hawaiian Islands (USA).
Red Sea, Gulf of Aquaba, Gulf of Aden, south Oman, Socotra (Yemen), east Somalia, East Africa to 28°S, Comoros, Madagascar, Seychelles, Aldabara, Réunion, Mauritius, Rodrígues, Chagos, Maldives, Laccadives, Sri Lanka, Andamans, west Thailand, Myanmar, Sumatra, Bali, Sangakkaki, Borneo, east Indonesia, Minado, Togean Islands, Sulawesi, Flores, Komodo Sunda Island, Raja Ampat, west Papua, Cocos-Keeling Islands, Christmas Island, Asmore, Scott Reef, Rowley Shoals, NW Australian coast, Phillippines, Sprately Island, Great Barrier Reef, Solomon Islands, Vanuatu, New Caledonia, Chesterfields, Elizabeth & Middleton Reefs, Lord Howe island, south Taiwan, Peng hu shan, Ryukyu, Kawhisi-jima, south Japan, Izu Is, Ogosawara, Palau, Yap, Pohnpei, Ifalik, Chuuk, Kapingamarangi, Kosrae, south Marianas, north Marianas, Marshall Islands, Wake Island, Fiji, Rotuma, Tonga, Uvea, Samoa, Tuvalu, Phoenix, Line Island, Society Islands, Tuamotos, Gambier, Marquesas, Austral Island, Rapa, and Pitcairn (Myer distributional database 2006).
Native:American Samoa; Australia; British Indian Ocean Territory; Brunei Darussalam; China; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Djibouti; Egypt; Eritrea; Fiji; French Polynesia; India; Indonesia; Israel; Japan; Jordan; Kenya; Kiribati; Korea, Republic of; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Micronesia, Federated States of ; Mozambique; Myanmar; Nauru; New Caledonia; Niue; Northern Mariana Islands; Oman; Palau; Papua New Guinea; Philippines; Pitcairn; Réunion; Samoa; Saudi Arabia; Seychelles; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tokelau; Tonga; Tuvalu; United States Minor Outlying Islands; Vanuatu; Wallis and Futuna; Yemen
|FAO Marine Fishing Areas:|
Indian Ocean – western; Indian Ocean – eastern; Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
V. louti is a widespread grouper species that is abundant in the Western Indian Ocean gradually reaching low density east to the Western Pacific. In areas with detailed fishery records, this species has declined sharply over 20 years period.
V. louti abundance patterns differ sharply over their range with the major contrasts being between the western Indian Ocean and the Western Pacific. In the west Pacific, using UVC, V. louti was found to be one of the less abundant serranids on the Great Barrier Reef within the 5 to 0 m depth range. Analysis by habitat on the northern GBR (Pears 2005) demonstrated greater abundances on exposed reef fronts.
Abundances are expressed as no. per 1,000 m².
Back reef 0
Front reef 0.25±0.2
Back reef 0.45±0.4
Front reef 1.3±0.6
On a north/south gradient on the Great Barrier Reef with habitats combined V. louti was found to be marginally more abundant in the north.
Localities: Lizard 0.1±0.02; Tvlle 0.2±0.05; McKay 0; Pompey 0.
The carbonate reef systems of the western Indian Ocean supports abundant populations of V. louti. Abundances of V. louti on these reefs are equivalent to those of Plectropomus leopardus on the Great Barrier Reef. Each species appears to have a similar ecological role in the different regions.
Sampling WIO (Seychelles) Abundances are expressed as no. per 1,000 m².
Regions: Grantic reefs (Mahe) 0.1±0.08; North Amirantes 8.2±1.4; South Amirantes 5.1±1.3; Farquahar Atoll 3.5±0.8.
Zeller (2006) provides some catch trends from the Northern Marianas, Guam and American Samoa.
See Figures 1, 2 and 3 in the Supplementary Material.
|Current Population Trend:||Stable|
|Habitat and Ecology:||General|
V. louti is a coral reef-associated species found at depths of 3 to 240 m. Yellow-edged lyretail are usually seen in clear-water areas at depths below 15 m. V. louti prefers islands and offshore reefs, rather than continental shores. There is evidence of ciguatera in this species in the western Indian Ocean (Opic et al. 1994).
This species feeds primarily on fishes, including a variety of coral-reef species; crustacean prey comprises crabs, shrimps, and stomatopods.
Morgans (1982) reported mature females of 33 cm standard length, and spawning, which occurred between December and February.
Robinson et al. in prep have provided details of the reproductive biology of V. louti in the Western Indian Ocean. The size by sex distribution tends to suggest protogyny (Heemstra and Randall 1993), with females ranging from 300 to 600 mm FL and males from 300 to 700 mm FL. However until these data are examined in terms of age structure associated with histological analysis of smaller/younger individuals, protogyny cannot be confirmed. Distribution of females reproductive activity over the annual cycle suggests two spawning peaks based on the distribution of GSI values and the presence of hydrated oocytes. The highest GSI values associated with the presence of hydrated oocyctes where in March April and October. In both periods GSI fell abruptly following the presumed spawning periods.
Demographic data are available for the Indian Ocean populations of V. louti (Grandcourt 2005).
Growth parameters; Linf 510 mm FL, K 0.48, M 0.28. The sample comprised individuals collected from Aldabara Atoll with Lmax 600 mm FL and Tmax 15 yrs.
The major threat to V. louti is overfishing. This species is also present in the aquarium trade and live fish food trade.
V. louti is fished over most of its range and contributes to the Live Reef Fish Food Trade (LRFT) (Lau and Li 2000). In the Western Indian Ocean (WIO), this species contributes to both local commercial (Grandcourt 2005) and Live Reef Food Fish Trade (Satter and Adams 2005). In the western and central Pacific V. louti has been fished intensively in the northern Mariana Islands for at least 25 years with landings maintained at 6 to 8 metric tonnes in the 1960s following by an increasing decline to 15 to 20% of this catch in the 1990s with this low rate being maintained through 2000 (Zeller 2006) (Fig 1 in the Supplementary Material). The recent Samoan fishery has shown fluctuating landings but an overall decline (Fig 2 in the Supplementary Material). The Guam fishery is erratic and relatively small with no trends (Fig 3 in the Supplementary Material). The combination of relatively low densities and declining catch rates indicates that this species is probably overfished in the West Pacific. Indian Ocean populations appear to be healthy although this species is considered to be one of the more important elements of the LRFT in the Maldives and as one of the eight most important species for export has a quota of 30,000 individuals (Sattar and Adams, 2005). Grandcourt (2005) suggests a fast growing high turnover species that maintains high abundance in the WIO (Pears 2005). However the magnitude of the decline in landings of this species in the West Pacific (Zeller 2006) and the evidence of declines in the Maldives associated with the LRFT suggests that this species is overexploited.
|Conservation Actions:||V. louti occurs in protected areas throughout its range.|
|Citation:||Choat, J.H., Craig, M. & Ferreira, B. 2008. Variola louti. The IUCN Red List of Threatened Species 2008: e.T132738A3437243.Downloaded on 19 November 2017.|
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