Seagrass meadows of the Solomon Islands, derived from field surveys conducted 13 May and 16 June 2004

Approximately 6,633 ±1,446 hectares (ha) of predominately intertidal and shallow subtidal seagrass meadows were mapped during the Solomon Islands Rapid Ecological Assessment (SIREA) between 13 May and 16 June 2004. This was the first comprehensive survey of the Solomon Islands and it focused on the main island group from Choiseul Island in the northwest to Makira in the southeast. The survey involved examination of 1,426 field validation sites/points and identified 486 individual meadows. 10 species of seagrass were identified throughout the Solomon Islands. Mapping survey methodologies followed standardised global seagrass research methods (McKenzie et al. 2001, doi:10.1016/B978-044450891-1/50006-2) where observers walked or free-dived to assess survey points. At each survey site/point seagrass % cover and/or above ground biomass (standing crop, grams dry weight (g DW/m**2)) was determined within quadrats (50cm x 50cm) using a non-destructive visual estimates of biomass technique and the seagrass species present identified. Water depth and visual/tactile description of sediment were also recorded at each survey site/point. A differential handheld global positioning system (GPS) was used to locate each survey site/point (accuracy ±5m). Seagrass meadow boundaries were determined based on the positions of survey sites and the presence of seagrass, coupled with depth contours and remote sensing (e.g. aerial photography) where available. The meadow boundary accuracy varied from 7.5m to 500m. The resulting data of each survey point and each seagrass meadow was saved as an ArcMap shapefile and projected to WGS84. Most Solomon Islands seagrasses were found in water shallower than 10m and meadows were monospecific or consisted of multispecies communities; up to 6 species present at a single location. The dominant species encountered were Enhalus acoroides and Thalassia hemprichii. 54% of all seagrass meadows (per hectare basis) were found in Malaita Province. All other provinces each included less than 12% of the seagrass meadows. Seagrass distribution appears to be primarily influenced by the degree of wave action (exposure) and nutrient availability. Solomon Islands' seagrass habitats can be generally categorised into four broad habitats: estuaries (incl. large shallow lagoons), coastal (incl. fringing reef), deep-water and reef (e.g., barrier or isolated)