Coral Bleaching and Restoration.
Definition.
Coral reefs are biological hotspots in that they harbor the highest number of biodiversity globally. They are feeding grounds for commercially important fish species. They also support sustainable livelihoods for small-scale and artisanal fisheries along Kenya’s coast. Reefs act as natural buffers against storms, waves, and floods that have great potential to damage property, cause erosion, and loss of human life.
A thriving coral
Introduction.
Corals are very sensitive animals that are bleached when they expel zooxanthellae, algae living in their tissues, turning completely white. Zooxanthellae give the corals their vibrant colors and provide food for the corals. Bleaching occurs when corals are stressed by changes in ambient environmental conditions. This can be brought about by pollution, temperature changes, and longer exposure to sunlight and air.
A bleached coral is not a dead coral. Corals have been observed to recover from mild bleaching when temperatures return to normal. Thermal stress is a major cause of bleaching and this can occur with seasonal changes. However, coral bleaching has been accelerated by higher ocean temperatures brought on by global climate change resulting in longer periods where corals are exposed to higher water temperatures than normal.
A bleached coral
Why do we put in efforts to try and restore them?
As the corals die and their structures erode, the reefs degrade leaving a shadow of their former glory and splendor. With corals having slow growth rates of 0.3 to 10 centimeters per year depending on the type of corals, coral reefs can take from 100000 to 30,000,000 years to fully form. This makes it harder and crucial for the reefs to recover.
We conserve corals not only for the protection of biological diversity and economic gains but also for our future generations. By ensuring that we reduce the threats to these organisms as much as possible, we ensure that future generations get to enjoy and benefit from them as much as the past and present generations.
Restored corals
On the ground.
Kenya lost 90% of its coral cover during the 1998 global bleaching event. Only 18%-40% of total coral cover has successfully recovered in the past decades. This has been enabled by continuous scientific monitoring, coral restoration efforts and improved enforcement in Marine protected areas in the country.
Watamu Marine National Park boasts of its beautiful coral reefs that attract thousands of visitors annually. No fishing activities are allowed in the park thus the reefs are protected from illegal and destructive fishing practices. Sadly, these coral reefs are threatened by changes in normal temperatures as bleaching has been noted in several colonies. The Kenya Wildlife Service together with A Rocha Kenya has been continuously monitoring the reefs within the park to determine bleaching and recovery rates.
A restored and now thriving coral
Going forward.
This year, our marine team together with the Kenya Wildlife Service researchers conducted surveys of 70 marked quadrats of different species in four reefs within the park. No bleaching was observed within these quadrants. However, mild bleaching was observed outside the quadrats in all reefs, especially at Bennet’s reef which is located north of the park.
Our marine biologists have said that this has been this year has had the least bleaching compared to previous years, check out our other post here. It was also noted that the recruitment rate for juveniles was high in all surveyed reefs.
