Tag Archives: coral

What do you need to start a garden?

Most common answers include dirt, seeds, water and sunlight, maybe a shovel. This is correct if you are trying to grow plants in your backyard, however the garden I want to start is for animals…

From March 14-16, I attended a training workshop on coral gardening, and now I hope to grow coral, a sessile marine animal, within the province of Romblon. Necessary inputs for gardening coral include 4in steel nails, mallet, zipties, pliers, saltwater, rocky substrate, and sunlight.* Branching corals are ideal for gardening because they are fast growing and can reproduce asexually from a fragment broken off a larger colony.

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Important note: No live corals were broken for the purpose of garden building! Instead we dove around a reef in search of already broken, but still living branching coral fragments, which we aptly called, “Corals of Opportunity” or CFOs. The CFOs may have been fragmented by boat anchors or local swimmers and will die unless they find a new anchor along the ocean floor.

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Before receiving my certification as an expert coral gardener, I participated in a land-based practicum.

Land-based training to secure corals before doing so underwater
Land-based training to secure corals before doing so underwater
The coral nursery unit. The corals shown are dead samples for our land training. For the real nursery live corals were used and the unit was prepared underwater.
The coral nursery unit. The corals shown are dead samples for our land training. For the real nursery live corals were used and the unit was prepared underwater.

While underwater, the nails are hammered into rock until secure. Then, a coral fragment is tightly fastened to the nail with a ziptie. Don’t forget to cut off any additional plastic from the ziptie, otherwise algae may begin to grow and invade your coral.

For smaller coral fragments, a Coral Nursery Unit may be built in shallower waters. The nursery is useful to give the fragments a head start in growing before transfer to the reef. It is also useful to ensure you have a consistent supply of coral fragments for long-term gardening.

Preparing the nursery unit in the shallows before we carried it deeper.
Preparing the nursery unit in the shallows before we carried it deeper.

As gorgeous and as tempting as it was to explore the depths of the gorgeous coral wall close to our site, instead the tasks of searching, hammering, fastening and cutting to create a new coral garden in the reef shallows was a much better use of the 3000psi of air in each of my 4 SCUBA tanks. By the conclusion of our 3-day workshop, 25 Peace Corps volunteers and 25 Filipino counterparts built 3 coral nursery units and attached over 100 coral fragments to a shallow, rocky reef in front of JPark Hotel on Mactan Island in Cebu. Go CRM!!!**

*Alternative methods include securing a large rope net to the ocean bottom and tying coral fragments so the entire net will grow into a continuous reef at the conclusion of the project.

**CRM or Coastal Resource Management is the title of the Peace Corps sector that I am a part of. Other possible sectors include Education or Children, Youth & Family (CYF).

Provincial Dive Team Training

One of my biggest projects at site is developing the Provincial Reef Assessment Team, a group of divers to conduct regular assessments of Romblon’s marine resources to ensure proper management. We hope to also identify areas for protection in the future. Here are some photos from our recent dive training session.

The Dive Team
The Dive Team

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We lay a 50m transect line and then record the substrate under the line to determine % coral coverage on a given reef.
We lay a 50m transect line and then record the substrate under the line to determine % coral coverage on a given reef.
We also conduct fish surveys of species diversity and abundance.
We also conduct fish surveys of species diversity and abundance.
And in typical Filipino style, our entire team can fit in one vehicle!
And in typical Filipino style, our entire team can fit in one vehicle!

Crown-of-Thorns

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The Crown-of-Thorns (CoT) sea star (Acanthaster planci) can pose serious threat to Pacific coral reefs. The CoT varies from traditional sea stars in that it may have anywhere from 7 to 23 limbs and possesses numerous, long, sharp, toxic spines. In normal quantities this invertebrate is an appropriate part of the Pacific reef ecosystem. However, recent, increased, massive outbreaks of CoTs are highly problematic because the CoT is a corallivore, meaning it feeds on coral. Thus, outbreaks have the potential to destroy entire reefs. The CoT eats the fleshy polyps of a stony coral colony leaving behind white scars of the remaining dead calcium carbonate coral skeleton. In a balanced ecosystem CoTs feed on fast-growing Acroporid coral species, however when CoT numbers are abundant they begin feeding on slow growing coral colonies like Porites, which can devastate reefs for many years into the future.

Natural predators of the adult CoT include titon triggerfish (Balistoides viridescens), white-spotted pufferfish (Arothron hispidus), napoleon wrasse, humphead wrasse (Cheilinus undulates), giant triton snails (Charonia tritonis) and painted shrimp (Hymenocera picta). Overfishing of these predators, particularly the Giant Triton, valued for its large, beautiful shell, may have led to increased CoT outbreaks. Furthermore, it is possible that our wastewater and fertilizer have also contributed to these outbreaks. Scientists theorize that nutrient-rich runoff into the ocean from human activities has enabled more CoT larvae to survive, because CoT larvae feed on planktonic algae and an increase in nutrients favors excessive algal growth. Thus more nutrients –> more algal –> more CoTs –> greater damage to coral reefs.

Methods of CoT control:

  • Land Disposal
    • Collect CoTs, handling them with large serving tongs. Bring them to land and bury them.
    • When stressed CoTs will attempt to spawn, therefore it is essential to remove them from the water as quickly as possible.
  • Cutting up and Crushing in situ
  • Tying in bags in water
  • Poison Injection (acetic acid or sodium bisulfate)
    • Injection causes the CoT to disintegrate
  • Using dead CoTs as material for compost has been practiced in Fiji

Currently, we are exploring these methods at my site and will be developing a removal program in the future!