|Scientific Name:||Acanthurus nigroris|
|Species Authority:||Valenciennes, 1835|
Acanthurus atramentatus (Jordan & Evermann, 1905)
Acanthurus bipunctatus Günther, 1861
Hepatus atramentatus Jordan & Evermann, 1905
Teuthis atrimentatus Jordan & Evermann, 1903
Acanthurus nigroris is an endemic species in the Hawaiian Islands and Johnston Atoll, Acanthurus nigros is valid for the species elsewhere in Oceania and the Great Barrier Reef. The genetic analyses, based on mtDNA cytochrome b sequences from a total of 544 Acanthurus nigroris samples, revealed a clear separation (d = 0.041) between individuals from the Hawaiian Archipelago and the rest of the Pacific indicating a cryptic species pair (Randall et al. submitted manuscript, DiBattista et al. 2011).
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Choat, J.H., McIlwain, J., Rocha, L.A., Clements, K.D., Abesamis, R., Myers, R., Nanola, C., Russell, B. & Stockwell, B.|
|Reviewer/s:||Davidson, L., Edgar, G. & Kulbicki, M.|
Acanthurus nigroris is widespread, common and abundant in most of its range. It is caught as food and is a minor component of the aquarium trade. There was no difference in abundance between the main Hawaiian islands and the Northwest Hawaiian Islands. 80% of its distribution is encompassed by the Papahanaumokuakea Marine National Monument. It is therefore listed as Least Concern.
|Range Description:||Acanthurus nigroris is an endemic species in the Hawaiian Islands and Johnston Atoll (Randall et al. submitted manuscript).|
Native:United States Minor Outlying Islands (Johnston I.)
|FAO Marine Fishing Areas:||
Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Randall et al. (1993) recorded A. nigroris from Midway Atoll, Northwestern Hawaiian Islands, as abundant outside the lagoon at depths of less than 2 to over 20 m. It is common and abundant in Hawaii after A. nigrofuscus and Z. flavescens. An average of 1600 kg/year is harvested in the Hawaiian commercial fishery (Hawaii Division of Aquatic Resources unpub. data). This species is collected as an aquarium fish in West Hawaii. The total number of individuals caught from FY 2005-2009 was 1,099 with a total value of $1,453 (Walsh et al. 2010).|
|Habitat and Ecology:||
Acanthurus nigroris is usually found in schools from a few to several hundred individuals and feeds primarily on plankton or filamentous algae (Myers 1991). This species is classified as a grazer (Green and Bellwood 2009). This habitat generalist occupies lagoons, seaward reefs, mixed coral and rubble, and sand (depth range: 1 to 90 m; Myers 1991). Long-distance dispersal in A. nigroris presumably occurs during the pelagic larval stage that lasts approximately 55 to 60 days, based on estimates from related surgeonfish (Doherty et al. 1995, Fisher et al. 2005).
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).
There are no major threats known for this species. There was no difference in abundance observed between the main Hawaiian Islands and Northwest Hawaiian Islands (L. Rocha pers. comm. 2010).
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).
|Conservation Actions:||There are no species-specific conservation measures in place for this species. However, its distribution overlaps several marine protected areas within its range. 80% of its distribution is within the Papahonamokuahkea National Marine Park.|
|Citation:||Choat, J.H., McIlwain, J., Rocha, L.A., Clements, K.D., Abesamis, R., Myers, R., Nanola, C., Russell, B. & Stockwell, B. 2012. Acanthurus nigroris. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 18 June 2013.|
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