Survey Methods of Coral Reefs

Manta-Tow Survey

The Manta Tow is one of a coral reef survey method by which a snorkel diver is towed behind a small boat to make direct observation on the condition of corals. The Manta Tow is carried out by a diver and a recorder on-board. The survey boat stops every 2 minutes and the snorkel diver reports the coral cover and the number of Crown-of-Thorns to the recorder. The recorder logs the location and time at which they stopped using a portable GPS receiver. The GPS receiver is set to record the survey path automatically. Visual observation is limited to the depth of about 10m, but the Manta Tow is advantageous in surveying large areas of reefs in a relatively short time period.

Manta-Tow Survey

Spot-Check Survey

The Spot-Check Survey is another survey method to evaluate the coral reef condition visually by snorkeling for a 15 minutes period. Since scuba diving equipments are not necessary, the survey of an area can be conducted in a short period of time. It can also be easily performed and many areas can be surveyed in a day.

Spot-Check Survey