|Scientific Name:||Acanthurus lineatus|
|Species Authority:||(Linnaeus, 1758)|
Acanthurus vittatus Bennett, 1828
Chaetodon lineatus Linnaeus, 1758
Ctenodon lineatus (Linnaeus, 1758)
Harpurus lineatus (Linnaeus, 1758)
Hepatus lineatus (Linnaeus, 1758)
Rhombotides lineatus (Linnaeus, 1758)
Teuthis lineatus (Linnaeus, 1758)
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Choat, J.H., McIlwain, J., Abesamis, R., Clements, K.D., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.|
|Reviewer/s:||Davidson, L., Edgar, G. & Kulbicki, M.|
Acanthurus lineatus is widespread throughout the Indo-Pacific region, is common and locally abundant. It is fished over many parts of it range and is a targeted commercial and ornamental species. There were significant reductions in biomass between fished and unfished areas in the Philippines (Stockwell et al. 2009). Densities of this species are considerably lower outside of marine reserves and in areas of high exploitation. In American Samoa, where this species is the most important of the reef fishes in subsistence and artisanal fisheries, there have been no indications of significant overfishing. Moreover, fishery independent surveys with fishery-dependent data showed a decline in fishing effort resulting in constant catch landings and catch-per-unit effort (Sabater and Carroll 2009). There are no significant population reductions reported in other parts of its range. It occurs in number of marine protected areas in parts of its distribution and is therefore listed as Least Concern.
|Range Description:||Acanthurus lineatus is widespread in the Indo-Pacific from the east coast of Africa to the Society Islands, Marquesas Islands, and Tuamotu Archipelago. There were two records from the Hawaiian Islands: from the southern end of the island of Hawaii and from Oahu; these are probably waifs (Randall 2001a).|
Native:American Samoa (American Samoa); Australia; Bangladesh; British Indian Ocean Territory; Brunei Darussalam; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Disputed Territory (Paracel Is., Spratly Is.); Fiji; French Polynesia; French Southern Territories (the) (Mozambique Channel Is.); Guam; India (Andaman Is., Nicobar Is.); Indonesia; Japan; Kenya; Kiribati (Gilbert Is., Kiribati Line Is., Phoenix Is.); Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Micronesia, Federated States of; Mozambique; Myanmar; Nauru; New Caledonia; Niue; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Réunion; Samoa; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Tokelau; Tonga; Tuvalu; United States Minor Outlying Islands (Howland-Baker Is., US Line Is., Wake Is.); Vanuatu; Viet Nam; Wallis and Futuna; Yemen
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
In Fagatale Bay, American Samoa, A. lineatus is a dominant species on the reef slope (Green et al. 1999). It was the eighth most dominant species in Tutuila, Aunuu, and Taema Banks, American Samoa, contributing 2.7% of total fish biomass and 1.9% of numerical abundance (Sabater and Tofaeono 2006). It is moderately common in Calamianes Islands, Puerto Princesa and San Vicente, Philippines, Milne Bay, Papua New Guinea and Raja Ampat, Indonesia where it is usually in shallow surge-affected areas (Werner and Allen 2000; Palawan Council for Sustainable Development unpub. data; Allen 2003, 2003b).
At Moorea, French Polynesia, SPOT satellite images allowed estimation of the surface area of fringing reef (1,076 ha), barrier reef (3,788 ha) and outer slop (493 ha). A total of 30,563 individuals were recorded in this area in fish visual surveys conducted from 1990-1993 (Lecchini et al. 2006).Visual census surveys of the Iboih coast, Weh Island, Indonesia, recorded fish densities of 19 individuals/750 m2 at Pantai sirkui, 13 individuals/750 m2 at Teupin Layeu and 9 individuals/750 m2 at Teluk Pelabuhan (Faculty of Mathematic and Natural Science 2007). It occurs in high densities on coral reefs - 0.4 fish/m2 - in American Samoa (Craig 1996).In American Samoa, 2007 commercial landings for Acanthurids totalled 10,338 lbs with an estimated value of $23, 586 USD (Department of Marine and Wildlife Resources and the Western Pacific Fishery Information Network 2009). From July 1990 through to June 1991, landings of Acanthurids (surgeonfish) totalled 13,431 lbs, or 9% of the total catch. This species and A. xanthopterus comprised 82% of the total Acanthurid catch. A. linetaus were caught almost exclusively by divers, and 78% of the catch was landed at night. From July 1990 through to June 1991, 4,054 lbs were landed in the study areas (Ponwith 1991). In 1994, A. lineatus ranked 2nd among all species harvested in small-scale fisheries in American Samoa. It accounted for 10% of the total catch of 295 tons (Department of Marine and Wildlife Resources unpub. data Pago-Pago, American Samoa). A. lineatus accounted for 39% by weight of artisanal catches and only 1-3% of subsistence catches (Craig et al. 1997).
In the outer islands of American Samoa, the annual harvest of 37.5 metric tonnes (mt) (82,584 lb) of a small-scale subsistence fishery consisted of a diverse array of coral reef fishes and invertebrates. Of the reef-associated catch of 21.4 mt, A. lineatus accounted for 24% of the catch (Craig 2008). In Guam it is the third most abundant surgeonfish in terms of landing. The numbers increased throughout the 1990s, which corresponded with an increase in spearfishing. Densities of this species are considerably lower outside of marine reserves and in areas of high exploitation. In Pohnpei, it is 15% of the total Acanthurid landing (Rhodes et al. 2008). This species makes up 5% of the total catch in Saipan for 2009 (P. Houk unpub. data).
In the central Philippines, density and biomass of herbivorous fish in reserves had positive relationships with duration of reserve protection. Acanthuridae and Labridae (parrotfishes) were the major families that increased in biomass inside reserves with duration of reserve protection. Herbivore biomass inside reserves compared to fished sites was on average 1.4, 4.8 and 8.1 times higher at 0.5 to 4, 5 to 7 and 8 to 11 years of protection, respectively. For A. lineatus, fished site mean biomass was recorded at 0.01 kg per 500 m2 while mean biomass recorded in 4 reserves were 0.13, 0.91 (5 to 7 years of protection), 1.67 and 19.59 (8 to 11 years of protection) (Stockwell et al. 2009).
|Habitat and Ecology:||
Acanthurus lineatus inhabits inshore coral reefs or rocky substrata exposed to wave action. It is strongly site-attached (Craig et al. 1997). It is most frequently encountered on shallow reef flats (Brown and Allen 2008). It is an aggressive territorial fish. It grazes on algal turfs mainly on thallate and filamentous red and green algae (Choat et al. 2002, 2004). It maintains feeding territories in shallow waters during the daytime but spends nights in deeper-water crevices where it is harvested by fishermen (Craig et al. 1997). Craig (1996) found that territorial and non-territorial A. lineatus where different individuals, with territorial fish being significantly larger.
The sexes are separate among the acanthurids (Reeson 1983). Acanthurids do not display obvious sexual dimorphism, males assume courtship colours (J.H. Choat pers. comm. 2010). It spawns year-round but primarily during the austral summer (October-February) in American Samoa (Craig et al. 1997). This species has been observed in early morning group spawning in Palau and Guam (Johannes 1981, Robertson 1983, J. McIlwain pers. comm. 2010) and late afternoon group spawning at Escape Reef, Great Barrier Reef (Robertson 1983). It is likely to form resident spawning aggregations (Domeier and Colin 1997). Pair spawning (Robertson 1983) and non-sex-specific color changes associated with spawning (Johannes 1981) have also been observed. In Palau, it was observed to spawn prior to the full moon and during the new moon from February-April. In Guam it was observed to spawn 3 days before the full moon in March-April on the outgoing tide (J. McIlwain pers. comm. 2010). In the GBR it spawns in December (Johannes 1981, Robertson 1983). Size at sexual maturity is 160 mm (Choat and Robertson 2002a). Larvae are transported through pelagic waters while adults live sedentary lives associated with the reef (Robertson 1983). It has a long pelagic larval stage (Randall 2005).
There were significant reductions in biomass between fished and protected areas reported in the Philippines (Stockwell et al. 2009). In American Samoa, indicators of fishing pressure did not point to significant overfishing over a 9-year period (Craig et al. 1997).
The status of reef fisheries in American Samoa has commonly been reported as over-exploited, however, comparing patterns and trends from fishery independent surveys with fishery-dependent data showed a significant decline in shoreline fishing effort and a non-significant decrease in boat-based effort, resulting in constant catch landings and catch-per-unit effort. Concurrent with the decline in fishing effort and constant catch landing was an increase in fish abundance and biomass for the targeted families. The decrease in fishing pressure occurred during a period of rapid population growth, indicating non-dependence of the general population on fishing, reflecting the change in the social and economic dynamics within the territory (Sabater and Carroll 2009).
Craig et al. (2008) showed that the current harvests of the subsistence fishery in outer islands of American Samoa is similar to those in historic and prehistoric periods, indicating that the fishery is harvested at a sustainable level.
Surgeonfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reef while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. The majority of surgeonfishes are exclusively found on coral reef habitat, and of these, approximately 80% are experiencing a greater than 30% loss of coral reef area and degradation of coral reef habitat quality across their distributions. However, more research is needed to understand the long-term effects of coral reef habitat loss and degradation on these species' populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that recruit into areas with live coral cover, especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats (Comeros-Raynal et al. 2012).
There are no species-specific conservation measures in place for this species. Its distribution overlaps several marine protected areas in parts of its range. In American Samoa, SCUBA fishery has been banned since 2001 by Executive Order and subsequently in 2002 by regulation (Green 2003). Night spearfishing has been banned as well (J.H. Choat pers. comm. 2010).
In Queensland, Australia, there is a recreational catch limit of 5 per species and a minimum size limit of 25 cm (Department of Primary Industries accessed 8 April 2010).
|Citation:||Choat, J.H., McIlwain, J., Abesamis, R., Clements, K.D., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Acanthurus lineatus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 June 2013.|
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