CoralTransplantation

Coral Transplantation

What is coral transplantation?

Definition

Coral transplantation can be defined as the physical relocation of coral from a site of inhospitable conditions to where the coral is more likely to thrive. According to Edwards and Clark (1999), "the primary objectives of coral transplantation are to improve reef ‘quality’ in terms of live coral cover, biodiversity and topographic complexity.” Therefore, coral transplantation may be implemented in order to move live coral in danger of destruction or poor conditions at one location to a transplantation site that may provide a more hospitable environment, or it may be implemented in order to assist in rebuilding a damaged or deteriorating site by moving coral from a healthy site to the less healthy one.

Benefits and Disadvantages

There are many advantages of coral transplantation that may give a community many reasons to choose to transplant coral. The fact that there is immediate increase in live coral cover is very appealing because being able to see positive results so quickly is encouraging to the community to maintain healthy reefs after they have been restored through coral transplantation. This, in turn, improves the aesthetics of a less diverse and less coral-abundant reef which can influence the tourism industry in a coastal area. Along with increased coral cover, there is increased coral recruitment, which is the addition of coral juveniles (planula) in the coral reef that settle themselves and become polyps. With increased coral cover, rugosity and the number of sheltered locations for other marine organisms also increase, which helps establish a functional and diverse coral reef ecosystem.

• Disbenefits
  • • loss of coral from donor sites
    • higher mortality rates and reduced growth rates of transplanted corals
    • attachment failure
    • reduced fecundity
    • disillusionment

Methods

Required conditions

• timing- For coral reefs overgrown with algae, introducing efficient algae-eating fish should be the first step. The sequences of inhabitants should be critically planned to ensure corals are able to survive. In the Eastern Mediterranean, rabbitfishes were able to successfully undermine the overgrown species and uncover suitable substrate for coral recruitment (?? citation)
• temperature
• turbidity
• water quality
• species present
• kind of coral- "The transplantation of scleractinian corals is now widely regarded as a potentially useful tool for the restoration of damaged reef habitats." (Yap, 2009)

Guidelines and Procedure

• ways to grow coral
  • Coral fragments broken off by storms or other means can be transplanted to labs or nurseries for further growth. Planulae can also be cultured in labs and taken to nurseries for growth. After they are suitable to thrive in the wild, the coral is then planted at the transplant site. An alternative method involves taking either these fragments or whole coral colonies, and transplanting them directly to a transplant site. (Note: transplant sites are the designated site that is more hospitable for the coral to survive.)
• attachment methods
  • Cement: This involves cementing the coral to a cement base then is then placed on the ground of the transplant site. It can be attached to the ground by cable ties.
  • Steel ties: This method involves attaching cable ties to the coral and then driving the other end into the ground to hold them in place.

Related studies

• British Virgin Islands
  • Elkhorn coral is a threatened species in the British Virgin Islands. A study took coral fragments that had been broken off by storms and transplanted them to a restoration site, where the coral fragments were then replanted to barren ground.
  • It was found that the corals reattached themselves after approximately 3 months, and became large adult corals after 4 years.
  • The methods described above required little training and could be done by recreational divers who volunteer.
• Maldive Islands
  • Several species in the Maldive Islands were transplanted and observed to compare growth rates and mortality rates. Whole coral colonies were transplanted and cemented into place on a reef flat that had been degraded due to coral mining.
    • Acropora hyacinthus had the highest mortality rates (50% in two years)
    • Porites lobata had the lowest mortality rates (2.8% in two years)
    • Acropora divaricata had a high growth rate with relatively low mortality.
  • The results concluded that the species transplanted needs to be selected with care. The results were compared to other studies as well, and it was concluded that whether fragments or whole colonies are transplanted influences survival. There is a higher mortality rate at higher energy sites. The success rates proved that coral transplantation should only be conducted when natural recovery is highly unlikely.
• St. John
  • A study conducted off of St. John Island (U.S.V.I) used storm-produced fragments of elkhorn, staghorn and finger corals. The fragments were moved from inhospitable habitats to other reefs. Cable ties were used to secure the fragments to the sea bottom of dead coral.
  • Survival rates were found to be low for all species. One-third died from bleaching, disease, and predators, while the other two-thirds died from physical displacement. This proved that cable ties were not the most effective method for reef reconstruction.
• Phillipines (4)
  • Whole coral colonies were taken from degraded sites to undisturbed sites. Most of the corals were attached to bare rock surfaces with cement. Some sites attached the coral with green plastic screens that the transplants were tied to. The changes in diversity of the sites were then studied.
  • The sites that used the plastic screens had in increase in the number of taxa present, and then began to decrease. The sites that used cement showed a small but steady increase in the number of taxa present. The study discouraged the movement of whole coral colonies, except in extreme cases where the coral will not rehabilitate on its own.
  • This study was designed to document the richness and abundance of different coral reef species due to the effects of coral transplantation of adult coral colonies, and to compare these characters at sites with and without coral transplants. Greater species richness and abundance were found at transplant sites compared to neighboring sites not receiving transplants and control sites over 100 meters from the transplant sites. This confirmed that the transplanted corals were responsible for the increased species diversity, and that organisms were not exchanged between the sites because the empty plots and control plots had similar species diversities.