Sanctuary Restoration Methods
The goal of restoration is to aid in the recovery of a damaged area to the condition it was before it was injured. Restoration techniques vary based on the type of habitat affected, the extent of the damage, and other factors specific to each grounding.
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To prevent a seagrass injury from growing larger and to prepare the site for seagrass recolonization, the hole or scar is filled with crushed limestone rock, often called “pea rock.” Over time, fine sediments fill the empty spaces between the pea rock, creating the desired bottom habitat in which seagrasses can grow. Another fill technique is the use of sediment-filled, biodegradable tubes which can hold any desired sediment grain size.
After filling in injury holes or scars, scientists may install bird roosting stakes throughout the injury site. Birds will rest on these stakes and naturally fertilize the sediment below.
Once the damaged areas have been filled with sediment and bird stakes have been installed, scientists determine whether surrounding seagrasses are likely to grow into the injury, or whether recolonization needs to be jump-started with seagrass transplants. When appropriate, restoration biologists collect seagrass from nearby “donor sites” and transplant them in the injury. When done carefully, seagrass transplants will grow together, expanding to fill in injured areas.
Ongoing monitoring of seagrass restoration sites within the sanctuary tracks the success of these restored areas and help sanctuary managers determine if additional restoration efforts are necessary.
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Timing is critical in terms of successfully restoring corals injured at a grounding site. Many corals which are toppled over during a grounding have a chance of survival if they can be turned so that their live side faces up. Sanctuary restoration biologists right overturned corals and begin the process of reattaching coral colonies. The goal of these biologists is to attach the corals in the same area of the reef from which they were originally located before being damaged.
Restoration biologists identify clean areas of reef structure to which they will attach the dislodged coral colonies. They may have to clean up the bottom or dead side of the coral, so that the coral will form a solid seal to the limestone rock. A special cement or expoxy that hardens underwater is used to attach the corals.
Initial restoration efforts may also include the removal or stabilization of loose rubble and sediment, which actually smother or even “sand blast” surrounding live coral. Restoration in the form of uprighting and reattaching corals to the substrate is most effective when performed shortly after an injury.
Large vessel groundings in the sanctuary have caused injuries so substantial that it was necessary to physically rebuild reef structures. These restorations are major marine construction projects that require considerable planning, equipment, materials and trained personnel to successfully implement.