Cleaning A Coral Nursery

Cleaning A Coral Nursery

May 2015. Around 10 volunteers from various dive centers on Phi Phi Island joined The Adventure Club to help with the task of cleaning a coral nursery, our monthly clean up and maintenance. This clean has to be done every month otherwise algae can grow unrestrained and smother the corals fragments in the nursery.

The Phi Phi Ley Coral Nursery has been an ongoing project now for nearly 10 years. In that time we have grown thousands of corals and transplanted them to damaged areas of natural reef to help restock and encourage coral growth. Corals are very fragile and slow growing. Even though we have targeted fast growing corals such as Acropora and Montipora, the growth rate of these corals is not more than a few millimeters per month.

Cleaning A Coral Nursery Is A Challenge

We just got back from the nursery maintenance work and after seeing loads of speedboats pull up and throw their anchors in, sometimes you have to ask yourself why bother? Managing a Coral Nursery is not easy and is not something you can decide to do one moment and then say “Nah. Not this month”. It’s an ongoing effort, which takes time, effort, equipment, boats, food, gasoline, a lot of money and last, but not least: a good supply of volunteers.

Our project is under pressure by numerous  environmental elements. Some marine life, such as crown of thorn seastars, drupella snails, and schools of parrotfish, graze on coral polyps and algae. In a perfect and balanced reef, these predations are not a threat to the reef, and instead help aid in the diversity of different coral species and the marine life that habitat them. As these animals graze on the reef they are essentially cleaning the reef and providing fresh substrate that will encourage other species of coral to settle. However, in an unbalanced reef these coral grazers can reduce the live coral cover that can cause a phase shift from a ‘coral-dominant’ phase to algae dominant phase.

Keeping The Coral Oxygenated

Corals need a good carbonate concentration in the water to grow. Carbon dioxide levels play an important role dictating the level of carbon carbonate. Carbon dioxide is absorbed by water with which it reacts to create carbonic acid. The acid release protons which combined with carbonate convert it to bicarbonate. This means the carbonate concentration declines as CO2 enters the water and will continue to decline as CO2 levels increase in our atmosphere.

Solely, coral grazing organisms on the reef would not usually be an issue if corals had the ability to regrow quickly, but the fact that carbonate concentration is declining slowing down the speed of calcification does not allow corals to ‘bounce’ back as quickly as they are being consumed.

The Tourism Effect Of Cleaning A Coral Nursery

And that brings us to the next factor. Tourism. The Artificial Reef and Coral Nursery areas have become popular sites for both scuba divers and snorkelers. This brings boats from all areas of the mainland that wish to take their guests to the best places they can. Unfortunately this increase in boat traffic also increases pollutants in the water such as gasoline, sun creams (which are highly toxic for corals), and human waste. Snorkelers are encouraged to feed the fish with bread and rice, but this causes the fish to neglect their usual duties of feeding on corals and more dominant fish fight off other fish in the area that otherwise would also be playing their role in the balance of health of the reef. To top, speedboats anchor instead of using mooring buoys. It can be disconcerting  to spend years growing a few corals only to see a speedboat anchor destroying them in a few seconds.

So Why Bother Cleaning A Coral Nursery?

So that brings us back to our original question. Why bother? Because? Because the ocean provides. MAN as a species relies on the resources that the ocean provides and the ocean relies on the health of the coral reef which ensures a healthy habitat for the millions of animal species that use it during their juvenile stages. Millions of people around the world rely on fish as their main source of food. One small effort would not be enough to make a difference, but maybe a thousand small efforts might.

By Published On: June 15th, 2015Categories: Coral Nursery
Coral Nursery RehabilitationCoral Rehabilitation Workshop - University of Missouri
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