|Scientific Name:||Halophila baillonii|
|Taxonomic Notes:||Halophila baillonii (or Halophila baillonis, syn.) has often been misidentified as H. decipiens. For example, all but one of the records in Puerto Rico of H. baillonii are actually H. decipiens (D. Ballantine pers. comm. 2007) and reports by R. Phillips (1961) of H. baillonii in Florida are H. decipiens and, on the east coast of Florida, are what has now been identified as H. johnsonii (J. Kenworthy pers. comm. 2007). Halophila baillonii is also misidentified as H. decipiens in the Humann and Deloach (2002) field guide.|
|Red List Category & Criteria:||Vulnerable B2ab(ii,iii) ver 3.1|
|Assessor(s):||Short, F.T., Carruthers, T.J.R., van Tussenbroek, B. & Zieman, J.|
|Reviewer(s):||Livingstone, S., Harwell, H. & Carpenter, K.E.|
The majority of the distribution of Halophila baillonii is found in the Caribbean region. It is a rare species and the global population is highly fragmented and is only known from approximately seven locations. There is much uncertainty about the status of this species and little is known about the relative abundance except that it is often found in dense monospecific meadows. There have been declines in Belize and Colombia, and this species was eradicated by a storm on the Pacific coast of Costa Rica. In Dry Tortugas and Brazil it was recorded, but despite recent surveys, has not been found again. The best evidence indicates that it is rare where previously recorded. Threats are coastal development, pollution and poor water quality. It is suspected that H. baillonii is declining throughout its range and because of its rarity, there is cause for concern. The area of occupancy (AOO) is estimated to be less than at total of 2,000 km², although this is difficult to measure because of insufficient surveys. To act on the side of caution, this species is listed as Vulnerable under criterion B2, meeting (a) severely fragmented populations with less than 10 locations, and (b) a continuing decline in AOO and the quality of the habitat.
Halophila baillonii has a severely fragmented distribution in the Caribbean Sea, with the record complicated by instances of species misidentification. It occurs in several sites in the Greater Antilles, Colombia and Venezuela, and extensively in Belize. In the Pacific, there is a confirmed record of H. baillonii in Costa Rica in the Guanacaste province in 1994, at a depth of two m with a herbarium sample in La Universidad de Costa Rica (J. Cortes pers. comm.). It was eradicated on the Pacific coast of Costa Rica in 1996 by a storm (Cortes 2001). Since 1994 this species has not been found on the Pacific coast of Costa Rica (J. Vireal pers. comm. 2008).
This species is known from approximately seven locations and has a severely fragmented population.
Native:Aruba; Belize; Bonaire, Sint Eustatius and Saba; Colombia; Curaçao; Guadeloupe; Venezuela, Bolivarian Republic of; Virgin Islands, U.S.
|FAO Marine Fishing Areas:||
Atlantic – southwest; Atlantic – western central
|Estimated area of occupancy (AOO) - km2:||<2,000km2|
|Number of Locations:||7|
|Lower depth limit (metres):||15|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Very little is known about the relative abundance of H. baillonii, except that it is a rare species in much of its range. In the Placencia Lagoon in central Belize it is found in dense monospecific meadows and it is declining (Short et al. 2006). It was eradicated on the Pacific coast of Costa Rica in 1996 by a storm (Cortes 2001).
Halophila baillonii is apparently rare or a waif distribution in the Dry Tortugas and Brazil since repeated surveys in these areas failed to record this species after the original record. Although often misidentified in Puerto Rico, there is at least one record from this area, but it is thought to be rare.
In Colombia, H. baillonii generally appears to be limited in distribution and has disappeared in several sites (F. Short pers. comm. 2008).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||In some places H. baillonii forms dense monospecific meadows, but can be sparse and rare in others. In southern Belize, H. baillonii forms dense monospecific meadows at depths of 1.4-2.5 m in fine sand (Green and Short 2003). In Placencia Lagoon, Belize, mono-species meadows are found extending into mangrove prop roots with depths ranging between 0.6 and 2.2 m on mud and fine sand. Halophila baillonii can sometimes be found intermixed with Thalassia testudinum, H. decipiens, Halodule beaudettei, and/or Caulerpa spp. It can be found at depths of between one and 15 m, but is most commonly found between one and three m depth (Short et al. 2006).
Very little is known about the biology of this species. Little is known about flowering frequency and nothing is known about seedbank recruitment (Zieman 1982, Hemminga and Duarte 2000, Larkum et al. 2006, Short et al. 2006).
Evidence shows H. baillonii to be a valuable food source for the West Indian Manatee. It also provides shelter for Brachidontes exustus and juvenile Ginglymostoma cirratum. Eucinostomus melanopterus and Trachinotus falcatus were observed to feed on the scorched mussels that live in these meadows, with gut analysis showing a mixture of B. exustus and H. baillonii remains (Short et al. 2006).
In Belize, this species has a broad distribution in coastal lagoon systems at Placencia, and the exposed coastal region of Barranco, along the northwest coast of the Gulf of Honduras (Short et al. 2006).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||1|
Halophila baillonii apparently does not do well in poor water quality conditions affected by development and watershed runoff (Short et al. 2006). It was eradicated by heavy storms on the Pacific coast of Costa Rica.
This species is vulnerable due to the fact that it appears to be naturally rare with a fragmented population.
|Conservation Actions:||This species is found in Marine Protected Areas (MPAs) in Columbia and Belize.|
|Citation:||Short, F.T., Carruthers, T.J.R., van Tussenbroek, B. & Zieman, J. 2010. Halophila baillonii. The IUCN Red List of Threatened Species 2010: e.T173382A7004500. http://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T173382A7004500.en . Downloaded on 10 October 2015.|
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