ArtificialReefs

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Artificial Reefs

What are Artificial Reefs?

An artificial reef is a human-made underwater structure that substitutes as a natural reef to form a habitat for marine life. Artificial reefs are placed in areas where there is little bottom topography or near coral reefs to attract marine populations. These structures are made from a variety of materials including shipwrecks, construction debris, oil rigs, concrete, and any other man-made materials.[1] Artificial reefs are placed in areas where there is little bottom topography or near coral reefs to attract marine populations. By providing shelter from predation and surfaces for encrusting organisms to grow on the man-made structure creates a habitat. Lower level food chain organisms attract predators increasing the biodiversity. As time passes the reef is characterized by sponges, hard and soft corals, algae, numerous fish species, crustaceans, and many other creatures. Artificial reefs may be intentional or unintentional, thus those that are not may carry impositions with them that can have adverse effects on the ecosystem.

Organism encrusted mooring line in St. Francis Bay, US Virgin Islands. Photo credit: Caroline Lowcher

Why Artificial Reefs?

Artificial reefs serve to protect coral reefs form human-induced damages. In addition, they are used for mitigating coastal erosion, creating surf breaks, and in the past have been built to block ships from entering coastal waters. These structures create plankton-rich feeding spots that attract small animals and the reef soon becomes covered by encrusting coral and sponges. The collection of smaller marine organisms brings in predators and expands to establish a new habitat. The significance of this is that these spots divert reef-dwellers like divers and boaters from endangered coral reefs to the artificial reef.[2][3] Not only do artificial reefs serve as protectors, but they can be used to maintain fisheries management and promote ecotourism for Small Island Developing States.

Fisheries Management

Fisheries management is how we interact with our aquatic resources in a way that is sustainable. This means controlling our behavior, marine habitats, and marine resources to produce optimum yield and estimate fish mortality. As a way to manage these components of fisheries, artificial reefs have begun to be implemented to manipulate marine habitats. It is easily mistaken that artificial reefs are an enoompassing solution to fisheries management since there are no adverse side effects, but there are very few applications of this and so there are limited examples to follow, and thus are few reefs used in this management. Establishing artificial reefs creates two scenarios that promote sustainability of fish populations and fishing. In one scenario the reef increases the environmental carrying capacity by establishing and additional habitat. This therefore increases biomass. In the other scenario the artificial reef serves to aggregate fish and makes them more vulnerable to being harvested by fishermen. One demonstration in fisheries management has been the deployment of concrete modules in Algarve, Portugal to build an artificial reef complex as part of the Algarve Artificial Reef Program. This program studied the colonization process, the role of reefs as nursery grounds for juvenile protection, fish and benthic invertebrate assemblage, water chemistry, the use by the fishing community, and the socio-economic impact on the local community. The results of this program include an increase in the mean number of species, a high level of biomass, confirmation of the increased proportion of fish as juveniles, and demonstrated the multiple roles artificial reefs serve for recruitment, nursery grounds, and reproduction for adults.[4]

http://ngm.nationalgeographic.com/2011/02/artificial-reefs/harrigan-text

Types of Artificial Reefs

Artificial reefs generally fall into two categories, manufactured and recycled. Though the purposes of artificial reefs may vary, effective reefs must be heavy, non-toxic, and resistant to erosion and other forms of physical and chemical wear.[5][6][7]

Manufactured

Most modern manufactured reefs have a bamboo fiber, synthetic fiber, or metal framework, which is then covered in a mixture of neutral-pH concrete and calcium carbonate (limestone). A higher proportion of concrete creates a stronger structure, however this increases the acidity of the structure, making it less habitable for coral polyps.[8]

Electro Mineral Accretion (EMA)

EMA is a method of crystallizing limestone on a metallic structure, via an electric current within a solution that contains dissolved calcium carbonate (limestone). A low voltage current is run through the structure, which can be generated by floating solar panels on the surface or by a battery. This current prevents rust and promotes the crystallization of the limestone, which is an attractive habitat for coral. The nooks and crannies of calcium carbonate formed this way are also highly appealing to small marine organisms.[9]

Mass produced and custom concrete structures

Organizations such as Reef Ball and Artificial Reefs, Inc. are currently at the forefront of artificial reef design and production. Due to the expense of production and placement, many NGO's are at the forefront of artificial reef design, placement, and purchase. The Reef Balls, Fish Condos, and other customizable structures undergo extensive testing to ensure their stability and resistance to the physical and chemical wear encountered in marine environments. The customizable aspects of these structures, such as variations in size, material, and other parameters can be utilized to provide an ideal habitat for a desired species in a specific region.[10]

File:Reef.jpg
[http://www.artificialreefs.com/ARIGalleries1.cfm?GalleryID=12&GalleryPictureID=69&division=1 Deployment of "fish haven" artificial reefs.

Recycled

extensive cleaning and prep required, mention tires

Public Transit Vehicles

Retired Ships

Retired tanks and other military equipment

Additional Types of Artificial Reefs

Art and sculpture reefs

Silent Evolution in Cancun

Memorial reefs

Neptune Reef - Ashes from cremation formed into artificial reef bases

Surfing reefs

Cables, Perth, Australia[11]


How Do Artificial Reefs Stack Up with Natural Reefs?

  • Note inconclusiveness and need for additional studies[12]

Advantages of Artificial

  • Can be placed in convenient and easily accessible locations[13]
  • Cheap recycled materials[14]
  • Can be calibrated specifically for their environment and specific organisms[15][16]
  • long term profit for tourism
  • Rapid colonization, high fish densities, and high catch rates[17][18]

Disadvantages of Artificial

  • Expensive transportation and labor
  • Recycled materials need extensive cleaning and stripping[19]
  • Possible introduction of toxins
  • large initial investment
  • Suggested that only 50 percent of artificial reefs meet their established goals[20][21]
  • Heavily exploited areas need significantly more help than just adding reef structures[22]

Eco-tourism and Artificial Reefs

  • New dive sites lead to new economic opportunities
  • Cheap option for developing tropical countries to attract tourists
  • Long term profit
  • Increased and easily located fish populations attract tourists interested in fishing[23]
  • Tourists attracted to reef destinations create a demand for hotels, restaurants, and other markets associated with tourists
  • All of the above while helping the oceans and increasing fish populations!


http://www.advancedaquarist.com/blog/a-thriving-artificial-coral-reef-is-big-business


References

  1. "What Are Artificial Reefs and Where Are They Located in the Mid-Atlantic? | Mid-Atlantic Coastal Environment." EPA. Environmental Protection Agency, 24 Jan. 2013. Web. 26 Feb. 2013.
  2. "What Are Artificial Reefs and Where Are They Located in the Mid-Atlantic? | Mid-Atlantic Coastal Environment." EPA. Environmental Protection Agency, 24 Jan. 2013. Web. 26 Feb. 2013.
  3. Heller, Greg. "Surfing A to Z." Artificial Reefs Explained. Surfline, n.d. Web. 26 Feb. 2013.
  4. Bortone, Stephen A. Artificial Reefs in Fisheries Management. Boca Raton, FL: CRC, 2011. Print.
  5. Carr, Mark H., and Hixon, Mark A. “Artificial Reefs: The Importance of Comparisons with Natural Reefs.” Fisheries 22.4 (1997) 28-33. Print. 26 Feb. 2013.
  6. Bohnsack, James A., and David L. Sutherland. "Artificial reef research: a review with recommendations for future priorities." Bulletin of Marine Science 37.1 (1985): 11-39. Print. 26 Feb. 2013.
  7. Baine, Mark. "Artificial reefs: a review of their design, application, management and performance." Ocean & Coastal Management 44.3 (2001): 241-259. Print. 26 Feb. 2013.
  8. Baine, Mark. "Artificial reefs: a review of their design, application, management and performance." Ocean & Coastal Management 44.3 (2001): 241-259. Print. 26 Feb. 2013.
  9. Taylor, Andrew CF. "ELECTRO MINERAL ACCRETION." Encyclopedia of Modern Coral Reefs: Structure, Form and Process (2011): 368.
  10. Bohnsack, James A., and David L. Sutherland. "Artificial reef research: a review with recommendations for future priorities." Bulletin of Marine Science 37.1 (1985): 11-39. Print. 26 Feb. 2013.
  11. Heller, Greg. "Surfing A to Z." Artificial Reefs Explained. Surfline, n.d. Web. 26 Feb. 2013.
  12. Bohnsack, James A., and David L. Sutherland. "Artificial reef research: a review with recommendations for future priorities." Bulletin of Marine Science 37.1 (1985): 11-39. Print. 26 Feb. 2013.
  13. Carr, Mark H., and Hixon, Mark A. “Artificial Reefs: The Importance of Comparisons with Natural Reefs.” Fisheries 22.4 (1997) 28-33. Print. 26 Feb. 2013.
  14. Baine, Mark. "Artificial reefs: a review of their design, application, management and performance." Ocean & Coastal Management 44.3 (2001): 241-259. Print. 26 Feb. 2013.
  15. Bohnsack, James A., and David L. Sutherland. "Artificial reef research: a review with recommendations for future priorities." Bulletin of Marine Science 37.1 (1985): 11-39. Print. 26 Feb. 2013.
  16. Baine, Mark. "Artificial reefs: a review of their design, application, management and performance." Ocean & Coastal Management 44.3 (2001): 241-259. Print. 26 Feb. 2013.
  17. Bohnsack, James A. "Are high densities of fishes at artificial reefs the result of habitat limitation or behavioral preference?." Bulletin of Marine Science 44.2 (1989): 631-645. Print. 26 Feb. 2013.
  18. Randall, John E. "An analysis of the fish populations of artificial and natural reefs in the Virgin Islands." Carib. J. Sci 3.1 (1963): 31-47. Print. 26 Feb. 2013.
  19. Baine, Mark. "Artificial reefs: a review of their design, application, management and performance." Ocean & Coastal Management 44.3 (2001): 241-259. Print. 26 Feb. 2013.
  20. Bohnsack, James A. "Are high densities of fishes at artificial reefs the result of habitat limitation or behavioral preference?." Bulletin of Marine Science 44.2 (1989): 631-645. Print. 26 Feb. 2013.
  21. Carr, Mark H., and Hixon, Mark A. “Artificial Reefs: The Importance of Comparisons with Natural Reefs.” Fisheries 22.4 (1997) 28-33. Print. 26 Feb. 2013.
  22. Carr, Mark H., and Hixon, Mark A. “Artificial Reefs: The Importance of Comparisons with Natural Reefs.” Fisheries 22.4 (1997) 28-33. Print. 26 Feb. 2013.
  23. Bohnsack, James A. "Are high densities of fishes at artificial reefs the result of habitat limitation or behavioral preference?." Bulletin of Marine Science 44.2 (1989): 631-645. Print. 26 Feb. 2013.
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