Although den Hartog’s (1970)³ “Sea-grasses of the world” did not list any species from Vanuatu, Cymodocea rotundata was reported as very common on the reef at Lamap (Port Sandwich, Malekula) in 1935-36⁴. During an expedition in August - September 1974, Taylor⁵confirmed C. rotundata remained common at Lamap, and also occurred in Erakor lagoon (Éfaté) and Palikoulo Bay (Espiritu Santo). During the same expedition, Taylor (1978)⁵ included incidental records of three more seagrasses: Halodule uninervis (Éfaté), Thalassia hemprichii (Lamap, Éfaté, Santo) and Ruppia sp. at Port Resolution (Tanna)⁵. In 1976, Halophila minor (mixed with Halodule uninervis, Cymodocea rotundata, and Thalassia hemprichii) was recorded near Malassa Village, on the northeast coast, and Mosso Islet off the northwest coast, of Éfaté⁶. This raised the number of recorded seagrass species in Vanuatu to five.

Apart from incidental records, the only extensive survey of seagrass species throughout Vanuatu was conducted as part of broad scale coastal marine ecosystems assessment in March - April 1988⁷). Sixty sites were assessed, from Aneityum in the south to Ureparapara in the north (8 locations were examined around Malakula Island) and seagrass was present at 39 of these ⁸. Most seagrasses were widely distributed throughout the islands. Nine seagrass species were recorded, six of which were new records for Vanuatu (Cymodocea serrulata, Enhalus acoroides, Halophila pinifolia, Halophila ovalis, Syringodium isoetifolium, Thalassodendron ciliatum). The most widespread species were Thalassia hemprichii, Cymodocea rotundata, Halodule uninervis, Enhalus acoroides and Halophila ovalis. Habitats in which seagrasses were found included: reef crest, reef or reef passage (12 sites); lagoon behind reef (21); bay (15); and intertidal (12)⁸. Seagrass diversity and abundance was lowest at reef habitats and greatest in the intertidal areas, and intermediate in lagoons and bays⁸. Most of the meadows were rather small, but extensive seagrass meadows were located on the comparatively wide intertidal areas around the Maskelyne Islands and along the southeast coast of Malakula.

After the 1970 – 80’s, expeditions examining seagrass across the archipelago did not occur until the new millennium. An expedition from Aneityum (Anatom) to Éfaté and Espiritu Santo in October - November 2001 reported additional records of Ruppia maritima L. var. pacifica from the river mouths at Anelgauhat (Aneityum) and the Adisone River (Espiritu Santo)⁹. The expedition also reported additional records of (C. rotundata, E. acoroides, H. pinifolia, H. uninervis, H. ovalis, S. isoetifolium, T. hemprichii) throughout the three islands¹⁰. An ecological baseline survey of the Amal/Crab Bay Tabu Eria (AKTE) on the eastern coast of central Malekula between November 2004 and May 2005 reported 3 species of seagrass¹¹. Seagrass was reported to dominate the large intertidal reef flats bordering the two headlands at the entrance to the bay. Hickey (2007)¹¹ hypothesized these headland fringing reefs were in uplift transition (following from a 1965 earthquake when the east coast of Malekula was uplifted approximately 1-m above mean high water), as they were largely intertidal and only isolated live coral heads occurred in deeper pools and along the seaward edges, suggesting they may be threatened by continued tectonic uplift. Four types of “seagrass” were defined by traditional knowledge in the AKTE including: a short seagrass called "food of the turtle" which dominated the large fringing reefs (almost certainly Thalassia hemprichii); a "long seagrass" which occurred closer to shore in the shallow lagoon (Enhalus acoroides); a finer seagrass found growing on fine sand in the vicinity of the mangrove islands also called "food of the turtle" and favoured by dugong (Hickey (2007)¹¹ suggests Halophila sp.); and an additional "seagrass", called "food of the dugong", which was identified as the saltmarsh plant Sesuvium portulacastrum (not a seagrass). Hickey (2007)¹¹ reported that dugongs were locally known to feed on this succulent herb on very high tides, and it was also a traditional food of Limap residents.

In August 2006, as part of the "Santo 2006 expedition", and extensive investigation of algal flora and seagrass was carried out in most of the habitats recognized in the southern part of Espiritu Santo, in the Luganville area; 42 sites were assessed by SCUBA divers to 60m depth, and included islands, shorelines, reef flats, channels and deep outer reef slopes¹². This was the first expedition to examine deeper waters (>4m) and it reported two new seagrass species (incl. range extension) for Vanuatu, Halophila capricorni and Halophila decipiens^13,12. The new records are not surprising as both species occur in New Caledonia and Vanuatu is within the species geographic range^14,15. To date, thirteen seagrass species have been confirmed from the waters of Vanuatu (Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, Halophila pinifolia, Halodule uninervis, Halophila capricorni, Halophila decipiens, Halophila minor, Halophila ovalis, Syringodium isoetifolium, Thalassodendron ciliatum, Thalassia hemprichii, and Ruppia maritima). The inclusion of Zostera capricorni in the Vanuatu seagrass list by Green and Short (2003)¹⁶ and Ellison (2009)¹⁷ is most likely in error, as it is not supported by a herbarium specimen and not within the species’ likely geographic range.

Vanuatu has a total of 44,800 hectares of nearshore habitats (i.e. areas less than 10 m in depth), which includes fringing reef, mangroves, seagrass meadows and estuarine habitats¹¹. Seagrass distribution throughout the region is most likely influenced by shelter, sediment characteristics, water clarity and tidal exposure. Much of Vanuatu's seagrass meadows appear restricted to narrow fringing and inner reef areas or sheltered bays, where they are generally reported to occur in scattered patches or form small meadows (e.g., <100m wide zones)^8,12. Pascal et al. (2015)¹⁸ estimated that Vanuatu’s seagrass meadows covered 1,500 hectares, however the source cited does not confirm the value¹⁹. To date, no comprehensive survey has mapped the seagrass resources of Vanuatu and their exact area/extent is unknown ¹⁹.

Seagrass ecosystems are a critical nearshore resource, which along with coral reefs and mangroves provide important socioeconomically services. Cillauren et al. (2001)²⁰ estimated that annual production by village fisheries from nearshore habitats in 1983 totalled 2,849 tonnes. A recent economic assessment of Vanuatu’s marine and coastal ecosystems (including open oceans, coral reefs, mangroves, seagrass, other soft seabed communities and seamounts) estimated the total economic value to be Vt 4,266 million (in 2013 Vatu), or US$ 48 million (in 2013 US dollars) per year¹⁸. The most economically important ecosystem service valued was coastal protection, followed by tourism and recreation, fisheries and support to research, management and education. Therefore the management of these habitats is of critical importance. The management of the nearshore areas is primarily vested with the traditional land custodians, through customary marine tenure (CMT) which is legally recognised in Vanuatu and enshrined in the Constitution. This provides customary owners the right to manage their land and reefs as they have traditionally done for centuries through a combination of traditional beliefs and practices, included privileged user’s rights, species-specific prohibitions, seasonal closures, food avoidance and tabu areas. Seagrasses in Vanuatu are also protected through other acts of legislation, including the Foreshore Development Act and the Environmental Protection and Conservation Act. The Environmental Impact Assessment Regulations, Order No. 175 of 2011, is significant in that the regulations specifically state that foreshore development activities which require preliminary environmental assessment include “(i) the clearance of any mangroves or the disturbance of any other coastal/estuarine ecosystem including seagrasses, coral, sand etc; or (ii) dredging.”