Eight Stages Toward Coral Reef Collapse

Coral reefs may look okay but on closer examination they may be dying. Overfishing, particularly in the Indian Ocean, causes eight steps that lead to reef collapse. Each step is a stage toward the end of a reef.

Keeping fish numbers up is important. When the level falls below 1000 kilograms of fish per hectare seaweed growth increases as well as urchin activity. This is a major indication of a problem. If fish density falls below 300 kilograms a crisis is reached.

Until now, coral cover has been used as a measure of coral health. This research shows that coral cover is the last threshold: the reef is heading toward ecosystem collapse.

It is during the first three stages that constructive change will save a reef. Fishing should be regulated. If a reef is in the final five stages, it is near impossible to save it. Only marine reserves have really healthy coral reefs because fishing is restricted. Unmonitored reefs fare the worst. A management system for each reef needs to be developed and put in place.
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