The oldest fossil found on coral reefs indicates their existence nearly 400 million years ago, positioning them as one of the oldest living species that have endured numerous changes in the Earth's environment.

They have been able to adapt to these changes and have remained resilient until the modern era, when human activities have led to the climate crisis. Consequently, the average global temperatures have risen, and we now live in the era of global warming.

Coral bleaching

Many coral reefs around the world have responded to global warming, and this is evident in the phenomenon of bleaching. This occurs when the waters are warm; the coral reefs suffer from thermal stress, during which the corals expel the algae they coexist with in a symbiotic relationship, called zooxanthellae. These algae give the coral reefs their bright and attractive colors. When these algae separate from the corals, the latter remain white and face death. Over the past 30 years, the phenomenon of coral bleaching has caused the loss of about 19% of the world's coral reef area. Alarmingly, the year 2024 witnessed the fourth largest coral bleaching event.

Fishing grounds

Coral reefs are among the most important systems supporting fisheries around the world, as they provide food, shelter, and breeding grounds. On the other hand, coral reefs benefit from fisheries, as fish provide some nutrients to the reefs. Therefore, it was necessary to consider the implications of coral bleaching, a result of global warming, on fisheries. This was the focus of a research group from the Woods Hole Oceanographic Institution in the United States. They discovered that coral bleaching has a negative impact on fisheries, and they published their findings in the journal "Marine Resource Economics" in November 2024.

Loss

Researchers analyzed data from about 9 fisheries that depend on the Great Barrier Reef in Australia between 2016 and 2020. The Great Barrier Reef includes around 400 species of coral, about 4,000 species of mollusks, and 1,500 species of fish. Despite being a unique biological heritage, the Great Barrier Reef is susceptible to bleaching phenomena. Indeed, in 2024, the Great Barrier Reef witnessed the worst bleaching event in its history. Researchers found that the loss of coral reefs leads to a decrease in the number of fish that depend on reef systems, such as trout, butterfly fish, and groupers.

The results indicated that if the coral reefs of the Great Barrier Reef decrease from 30% to 25%, it could lead to an 8% reduction in the yield of trout fish, while the yield of grouper fish would decrease by 19%. However, if the coral cover shrinks from 10% to 5%, the yield of trout fish could drop by 27%, while the grouper fish yield would decrease by 56%. Researchers believe that restoring coral reefs should be a priority; these systems support about 25% of marine life and are also a strong source of income through the tourism sector.