Restoring Coral Reefs through Coral Nurseries

By Brittany Domke 
From May 17, 2018
​Today in Tropical Marine Ecology and Conservation, I conducted four coral reef dive cleanups. One of the dives was located near Rachette Point and contained a coral reef nursery. A coral nursery contains fragments of corals that are collected from local coral reefs, raised in nurseries until large enough to be outplanted, and then installed at the restoration site. Corals are grown in these nurseries for about six to nine months before planting them in local sites. Coral reefs are the "rainforests of the sea" and are some of the most biodiverse and productive ecosystems on earth. Corals can grow and reproduce both sexually, through spawning, and asexually, through fragmentation. The corals are placed in rows on PVC pipes that resemble a tree framework and are hung by monofilament lines which are typically placed near other healthy coral reefs. The PVC tree is tethered to a buoy and can move with wave surge and provide corals with better water circulation. This field-based process has many advantages, particularly aiding in a higher survival rate for corals and providing relatively low costs and simple technology. Factors influencing nursery success include size, location, depth, design, and structure. The two main types of coral nursery deigns are floating nurseries and fixed nurseries. Floating nurseries involve suspending PVC trees using subsurface floats and attaching them to the seafloor with anchors. Fixed nursery structures involve securing corals to cinder blocks or cement slabs that are anchored to the seafloor. The two most common species grown in coral nurseries are elkhorn and staghorn coral. An interesting fact is that, staghorn and elkhorn coral are the fastest growing corals in the world with staghorn growing up to eight inches in a year while elkhorn can grow up to four inches. Scientist are investigating the best new ways to manage and raise some of the slower growing coral species such as boulder star coral and lobed star coral.
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Another coral conservation strategy is the implementation of artificial reefs. Artificial reefs are human made structures made of anything ranging from sunken shipwrecks, sculptures, government military tanks, and even concrete blocks. Biorock is another method used for coral restoration and was first introduced in the 1970’s. It is based on an electro-accumulation of mineral accretion technology invented by Professor Wolf Hilbertz and Dr. Tom Goreau. This process mimics the formation of calcium carbonate by the electrodes which corals are made from. Coral reefs have decreased dramatically around the world which can lead to possible extinction thereby leading to decrease in fish populations. The decline in coral populations is caused by coral bleaching, coral mining, pollution, fertilization runoff, coastal development, introduced diseases, and overfishing. This can be detrimental to marine habitats and populations. Most countries, especially Caribbean nations, rely on revenue from tourism and organizations like the SMMA are not government funded. Scientists have found that this type of coral restoration strategy could be the most efficient way to restore coral reefs and aid in increasing populations. The coral reef nurseries are used to revive and protect vulnerable coral reefs that are at risk. This specific coral nursery I observed is protected by the SMMA (Soufriere Marine Management Association) which is a non-profit organization whose goal is to conserve the natural marine environment and ensure the development of five zones, including Marine Reserves, Fishing Priority Areas, Multiple Use Areas, Yatch Mooring Areas, and Recreation Areas particularly with in the fishing and tourism district.