GMSA Mapping Protocol

A distribution map is created for every species that is assessed under the Red List Criteria for the GMSA initiative. The extent of the distribution for each species is based on point data from collected specimens via scientific expeditions and fishery bycatch. The specimen records for the GMSA distribution maps come from published journal articles and books, fisheries data, museum collections, and FishBase.

During the Red List workshops, the distribution of each species is viewed by the expert participants. In this way they are refined and verified, removing and adding range where appropriate. The workshop acts as a peer review process, so that the GMSA maps are up-to-date and reliable.

Map creation
The species distribution maps are produced using the software ArcView 3.3 and ArcGIS 9.1. Marine basemaps were created using buffered fixed distances from the shore and bathymetry data. A number of standard basemaps of all possible habitat ranges were created. This was done for each marine region (e.g. Eastern Tropical Pacific, Indo-Pacific and Mediterranean). These basemaps were then used as a guide to clip species-specific distribution maps.

For species occurring within a very narrow range or those that are endemic, the ArcView 3.3 software is used to create polygons and shapefiles to represent species distribution range.

Habitat maps were created and plotted by adding a shape (graphics) to a view using the Draw polygon tool from the drop down column in ArcView 3.3. Each species of fish, coral, and seagrass has its own view, which can be projected alone or concurrently with other distribution maps depending on the query or species of interest.

Species-specific distribution maps are converted to .tiff files with a resolution of 600 dpi for review purpose for the Red List process.

Some examples of GMSA distribution maps are shown below: