Coral Reefs

, Volume 23, Issue 1, pp 161–168 | Cite as

Inventory of the Maldives’ coral reefs using morphometrics generated from Landsat ETM+ imagery

  • Abdulla Naseer
  • Bruce G. Hatcher


In this study, we present exact measures of the number, area, and basic morphometric statistics for every single reef of the Maldivian archipelago, as derived from the interpretation of remotely sensed data collected by the Landsat-7 ETM+ earth-observing satellite sensor. We classified and mapped seven morphological attributes of reefs (six marine habitats and reef-top islands) to 30-m depth at 30×30 m spatial resolution (pixel size) for the entire archipelago. The total archipelagic area (all coral reef and lagoon habitats) of the 16 atolls, five oceanic faros, and four oceanic platform reefs which comprise the Maldives is 21,372.72±1,068.64 km2 (approx. 20% of the Maldives’ Territorial Sea). A total of 2,041±10 distinct coral reef structures larger than 0.01 km2 occur in the Maldives, covering an area of 4,493.85 km2 (including enclosed reef lagoons and islands) to 30-m depth. Smaller areas of coral reef substratum cover another 19.29 km2, bringing the total area of Maldivian coral reefs to 4,513.14±225.65 km2. Shallow coral platforms thus occupy 21.1% of the total area of the archipelago (0.0052% of the EEZ area of the Maldives). Of these reefs, 538 are rim and oceanic reefs, covering 3,701.93 km2 (82.5% of the total reef area), and 1,503 are patch reefs within the atoll lagoons, covering 791.92 km2 (17.5% of the total reef area). Islands occupy only 5.1% of the total reef area. Mapping the Maldives’ coral reefs at high spatial resolution is only possible with remote sensing and spatial analysis technologies. These greatly reduce the large uncertainty around current estimates of reef area. Our accurate measure of total reef area is only 50.6% of the current best estimate, a result having significant implications for predictions of the Maldives’ reef productivity and response to global climate change. Here we present current best practice and compare the methods and measures with previous approaches.


Maldives Coral reef area Remote sensing Geographic information system 



We appreciate the inclusion and scheduling of Landsat-7 ETM+ images of the Maldives by the NASA Long Term data Acquisition Program (LTAP), and acknowledge the provision of six images by Serge Andréfouët through the Institute for Marine Remote Sensing at the University of South Florida. Serge also provided advice on protocols for reef classification using satellite imagery, for which we are very grateful. We thank the staff of the Ministry of Fisheries, Agriculture and Marine Resources, Government of the Maldives, and Canadian Fishery Consultants Ltd. for supporting the ground-truthing expedition. Funding for A. Naseer’s work was obtained from the Canadian Commonwealth Scholarship Fund. Partial support for B.G. Hatcher’s involvement was provided by the National Science and Engineering Research Council of Canada, Dalhousie University, and Canadian Fishery Consultants Ltd.


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Department of BiologyDalhousie UniversityHalifaxCanada
  2. 2.Marine Affairs ProgramDalhousie UniversityHalifaxCanada
  3. 3.Marine Research CenterH. White WavesMaléMaldives

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