|Scientific Name:||Halophila hawaiiana|
|Species Authority:||Doty & B.C.Stone|
|Taxonomic Notes:||Halophila hawaiiana is a member of the Halophila ovalis complex, and is under taxonomic review.|
|Red List Category & Criteria:||Vulnerable A2ce ver 3.1|
|Assessor/s:||Short, F.T., Coles, R., Waycott, M., Bujang, J.S., Fortes, M., Prathep, A., Kamal, A.H.M., Jagtap, T.G., Bandeira, S., Freeman, A., Erftemeijer, P., La Nafie, Y.A., Vergara, S., Calumpong, H.P. & Makm, I.|
|Reviewer/s:||Livingstone, S., Harwell, H. & Carpenter, K.E.|
Halophila hawaiiana is endemic to the Hawaiian Islands. It is locally common, however the overall population trend is declining. The species has a restricted distribution and a narrow depth range. In some areas this species has been replaced by invasive algal species and it is also highly threatened by shoreline development and beach replenishment. It estimated that there has been a greater than 30% decline in population over the past 10 years and therefore reaches the threshold under A criterion. It is listed as Vulnerable.
|Range Description:||Halophila hawaiiana is endemic to the Hawaiian Islands, USA. It is not found on the island of Hawaii. Given its very shallow depth range and patchy occurrence, it has an area of occupancy estimated to be less than 2000 km2.|
Native:United States (Hawaiian Is.)
|FAO Marine Fishing Areas:||
Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The overall population trend for Halophila hawaiiana is declining due to competition with algal species, shoreline development and beach replenishment. There has been an estimated decline of at least 30% over at least the past 10 years (M. Waycott pers. comm. 2008). Halophila hawaiiana can be locally common, and can occur in dense meadows.|
|Habitat and Ecology:||Halophila hawaiiana is found in the shallow subtidal zone in sandy protected areas. This species flowers relatively quickly. More information is needed on recruitment rate. This species has a high turnover rate, and is fast growing. The average leaf density of this species is 30,650 leaves/m². Its turnover rate is 14.7 days with a productivity of 7.11 g dw/m²/d (Herbert 1986).|
|Major Threat(s):||Halophila hawaiiana has a restricted distribution and is endemic to the Hawaiian Islands, thus making it of a higher extinction risk. It also has a narrow depth range. The habitat of this species has been taken over by invasive algal species in some parts of its range, resulting in declines. It is also highly threatened by shoreline development and beach replenishment.|
Halophila hawaiiana is present in the Northwestern Hawaiian Islands World Heritage Site.
More information is needed on recruitment rates and taxonomy of H. hawaiiana.
Green, E.P. and Short, F.T. 2003. World Atlas of Seagrasses. University of California Press, Berkeley.
Herbert, D.A. 1986. The growth dynamics of Halophila hawaiiana. Aquatic Botany 23: 351-360.
IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.3). Available at: http://www.iucnredlist.org. (Accessed: 2 September 2010).
|Citation:||Short, F.T., Coles, R., Waycott, M., Bujang, J.S., Fortes, M., Prathep, A., Kamal, A.H.M., Jagtap, T.G., Bandeira, S., Freeman, A., Erftemeijer, P., La Nafie, Y.A., Vergara, S., Calumpong, H.P. & Makm, I. 2010. Halophila hawaiiana. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 11 December 2013.|
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