Reef Check Surveys

Reef Check - At a Glance:

Reef Check (RC) is the most widely used coral reef monitoring protocol. The techniques are simple to learn and the data are scientifically robust. Reef Check data (and projects) are managed by the Reef Check Foundation, which is an international marine conservation organization based in Los Angeles, California with offices in the Philippines, Indonesia, the Dominican Republic and Australia and teams in over 80 countries and territories.

The Reef Check program brings together community groups, government departments, academia and business partners to:

  • Educate the public about the coral reef crisis;
  • Create a global network of volunteer teams to regularly monitor and report on reef health;
  • Scientifically investigate coral reef ecosystem processes;
  • Facilitate collaboration among academia, NGOs, governments and business;
  • Stimulate local community action to protect remaining pristine reefs and rehabilitate damaged reefs worldwide using ecologically sound and economically sustainable


Reef Check - The History:

Scientists have been monitoring coral reefs since the time of Darwin in the 1850s. But the introduction of scuba diving in the 1960s allowed scientists a new view of reefs that was documented and brought into the public domain by natural historians such as Jacques Cousteau. During the 1980s, many divers and scientists began to witness a decline in coral reef health at their favorite reefs, particularly at well-studied reefs such as in Jamaica. While accepting that certain reefs had been degraded, some scientists questioned the geographic extent of this issue. The 1993 Colloquium on Global Aspects of Coral Reefs (organized by Professor Robert Ginsburg of the University of Miami) was a turning point for many reef scientists who met to discuss the health of the world's reefs. Some scientists felt that most coral reefs were in serious trouble while others thought that only a few reefs were experiencing a temporary downturn in health. At the end of the meeting, it was clear that there was not enough information available to form a picture of the status of coral reefs on a global scale because there was no organized attempt to gather data.  

In 1997, scientists were invited to volunteer as Reef Check Trainers and the first-ever global survey of coral reef health was carried out in 31 countries in all tropical seas. The
results provided scientific confirmation that coral reefs were facing a major crisis on a global scale. In the 1980s, many scientists thought that the major threats to coral reefs were primarily pollution and sedimentation. The Reef Check results demonstrated for the first time, that overfishing was a major threat to coral reefs throughout the world (Hodgson, 1999). Since then, hundreds of Reef Check teams have been monitoring reefs every year and the number of participating countries is more than 80 out of the 101 with coral reefs.

In 2000, the non-profit 501c3 Reef Check Foundation was established in California to manage the annual survey and to create more opportunities for coral reef conservation.
Reef Check has many partners, but places special attention on establishing long-term partnerships with businesses such as the tourism, diving, surfing and the marine aquarium industries.

At the international level, Reef Check (RC) serves as the community-based component of the Global Coral Reef Monitoring Network (GCRMN) and collaborates on regular status reports. Reef Check is a member of the International Coral Reef Initiative (ICRI) and International Coral Reef Action Network (ICRAN). Reef Check provides data to and is developing interactive reef monitoring data management systems with ReefBase, the global database of coral reef information.


Reef Check - Monitoring Protocol Overview:

Reef Check was designed to assess the health of coral reefs and is quite different from other monitoring protocols. Since its inception, Reef Check has focused on the abundance of particular coral reef organisms that best reflect the condition of the ecosystem and that are easily recognizable to the general public. Selection of these “indicator” organisms was based on their economic and ecological value, their sensitivity to human impacts and ease of identification. Sixteen global and eight regional indicator organisms serve as specific measures of human impacts on coral reefs. These indicators include a broad spectrum of fish, invertebrates and plants that indicate human activities such as fishing, collection or pollution. Some Reef Check categories are individual species while others are families. For example, the humphead wrasse (Cheilinus undulatus) is the most sought after fish in the live food fish trade, whereas the banded coral shrimp (Stenopus hispidus) is collected for the aquarium trade. Both species are very distinctive organisms and excellent indicators of human predation. On reefs where these organisms are heavily exploited, their numbers are expected to be low compared to their abundance on unexploited reefs.

Reef Check teams collect four types of data:

  1. A description of each reef site based on over 30 measures of environmental and socio-economic conditions and ratings of human impacts;
  2. A measure of the percentage of the seabed covered by different substrate types, including live and dead coral, along four 20 m sections of a 100 m shallow reef
  3. Invertebrate counts over four, 20 m x 5 m belts along the transect;
  4. Fish counts, up to 5 m above the same belt.

Monitoring of the indicators is done along two depth contours. “Manta tows” are recommended as a habitat mapping and site selection technique in areas with sufficiently
clear water (> 6 m horizontal visibility). This easy to learn but scientifically robust sampling method is providing data on the condition of reef environments throughout the world and has been adopted as the standard monitoring protocol by marine park managers, national governments, scientific institutions as well as many volunteer teams. The methods have proven to be an effective learning tool for people wishing to gain more knowledge about coral reefs and the marine environment. They are also fun to do, attracting recreational divers wanting to experience coral reefs in a new way, as well as scientific divers wanting to improve their knowledge of taxonomy and ecology.