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Aquaculture and Mariculture

Aquaculture is the process of hatching or harvesting and rearing of marine life for human consumption; this is broken down into extensive and intensive aquaculture. Aquaculture is being used for many reasons including deterring over-fishing, increasing profit, and allow for genetic modification of marine life. [1]

  • Extensive aquaculture does not require the addition of feed [1]. Examples of this includes shellfish and seaweed which filter feed or perform photosynthesis.
  • Intensive aquaculture requires the addition of feed [1]. Examples of this includes herbivore, omnivore or carnivorous marine life such as salmon or shrimp.

Types of aquaculture

International aquaculture can be broken down into the following three categories:

  • One fourth of aquaculture is bivalves which includes clams, mussels and scallops. [2] This aquaculture is for food.
  • One fourth of aquaculture is seaweed and algae. [2] This aquacutlute is largely produced for chemicals to be used in health products and body products. [2] Some are raised for food.
  • Half of aquaculture is fish and other marine life. [2] Salmon is the largest market value produced within aquaculture and thus is a large segment of production. [2] Other aquaculture that fall in this category are shrimp, crustaceans and other fish including Caribbean fish.

Methods of Aquaculture[3]

There is a large variety of aquaculture due to the large variety of creatures and plants in aquaculture. Each method varies in their environmental harm as well. Two colloquial terms often used in aquaculture are ranching and farming. These two terms do not have definitions that are thoroughly defined but are often used in discussion with the distinction being that in fish ranching involves having the fish hatch and grow in one area and then releasing the fish and recapturing them when they return to spawn, this is common with salmon. Farming involves hatching, growth and harvesting in one area.

Beginning with filter feeders is the method of bag rack where bags are secured to racks to the bottom of the seabed with clams or other filter feeders, and grown until harvest. They are typically raised in shallow areas. Another common method to filter feeders is suspended line in which clams or seaweed grow off of suspended lines that hang in the water. These method generally has low environmental impact since the creatures are filter feeders and do not require inputs but if they are raised in still water then waste can become concentrated. Furthermore, introduction of invasive species can also commonly occur.

Hatcheries are used for sea creatures, commonly fish, and occur in large tanks where fish are raised from eggs within the tanks. The fish are either then collected from the hatchery or are released to be caught. The fish are often weaker than the wild species since they were grown in such sterilized areas free of competition and thus there is concern that hatched fish breeding with wild fish depletes the strength of the wild fish population.

Open Net Pens are used in standing water and are pens that are often in still standing water where fished are raised to be caught. They are held in tightly confined areas commonly so waste concentration and disease are very significant issues. Also similar to hatcheries there is a fear of these populations depleting the strength of wild populations. Furthermore, the waste created from this method can result in harm to many other life forms in the body of water they are raised in.

Last is recirculating pens which are largely preliminary at this point but are being celebrated for reduction in environmental impacts since they constantly move water and are located in created structures as opposed to standing bodies of water.

Potential Mitigation of Over-fishing

Over-fishing occurs when fish species are caught at a quicker rate than the rate at which they reproduce. This is a result of the increasing demand for fish across the world, as well as the unsustainable management of fisheries. It is predicted that by 2030 50% of fish consumption could be from aquaculture [4] Because of this, the rate of fish harvesting needs to be sustainable in order to maintain a sustainable juveniles population in order to obtain a balanced ecosystem. By removing certain species from a coral reef habitat, the coral reef food web is thrown into a state of imbalance, increasing the likelihood that other connected species will suffer negatively. [5]

Over-fishing externalities can be grouped into three main categories. Though there can exist other specific impacts, the main three cover the most common and most drastic results of this practice.[6]

  • Overfishing causes the destruction of the ecosystem in and around the coral reef. As with many unsustainable practices,
  • The collection of herbivorous fish and creatures -due to overfishing- can lead to excess algae. This excess algae creates a major imbalance in that ecosystem, potentially destroying the habitat of many other organisms.
  • The fishing techniques used in fishing can destroy coral. In the case of over-fishing, these harmful fishing techniques and their impacts are multiplied to a greater impact.

There currently exists alternative examples that help relieve the demand on fish and ameliorating the current food status of aquaculture.

  • Urban aquaculture is entirely dependent on the development of fisheries, and there currently exist big city-aquaculture that provides fish and other aquaculture products in areas such as New York City. This provides direct access to fresh fish, as well as creating a new market for job opportunities. [7]
  • The development of fisheries on the global scale has additionally led to poverty reduction. For those who perform aquaculture in Bangladesh for example, this has helped boost the local economy and improve overall health. [8]

Impacts on Coral

Coral reefs are used to provide an ecosystem for aquaculture farming. By using these coral reefs as fishery habitats, there are additional impacts on the coral. One of most prevalent results of aquaculture is its contribution to algae blooms.[9] As aquaculture contributes to algae blooms, this is due to the resulting waste, which provides more nutrients for algae. Fish waste and the additional nutrients used in aquaculture drastically increase algae bools. This algae bloom is detrimental to coral reefs, as the algae grows at the expense of coral, taking up the available sunlight and nutrients. The rising sea temperatures -due to climate change- promote ocean acidification, as these rising temperatures increase carbon dioxide concentration. This increased carbon dioxide concentration additional increases algae growth, as the algae blooms thrive with additional carbon dioxide.[10]

  • Salmon farming is often linked to large amounts of algae bloom; due to both the nutrient-loading of salmon, as well as the excess excrement of this salmon population. Conversely, algae bloom can negatively impact salmon farming, growing in the salmon pens and killing the fish. Heterosigma akashiwo is one of the more detrimental types of algae; it is especially invasive during late summer and early fall; and grows in high density, in certain cases high enough to suffocate fish.[11]

There exist various types of aquaculture purposes currently used today. These vary depending on the usage behind this aquaculture. While most types of fisheries utilize either cage culture or fishery pens, these methods are used for purposes other than consumption. [1]

  • Restocking is an example of this, and is the release of aquatic animals bred in captivity or collected elsewhere. This is done in habitats where there is a lack in the specific species, and helps maintain relative balance in the ecosystem.[1]
  • Reseeding is the release of aquatic plants bred in captivity or collected elsewhere. Like restocking, this is done to replenish lacking species, and ensure relative stability in the environment.[1]
  • Artificial Habitat Development is a recent practice, and is focused especially in the Great Barrier reef to help reconstruct this habitat. Using restocking and reseeding practices, this is a developing field used to address the rising damages in coral reef ecosystems. [1]



Increased pollution along coast from concentration of aquaculture has become a large problem. [5] As mentioned previously, this waste is concentrated fish fecal and is often concentrated near the fish pens. [5] The waste can lead to excessive amounts of nitrogen and other elements that result in algae blooms, destroying many habitats.

GMO Salmon

AquaBoutny Technologies has created a GMO salmon that grows twice as fast as normal salmon and twice as large to increase the amount of inputs needed and increase profits. [12] This is one of the uses of aquaculture is the ability to cultivate genetically engineered fish. This techonology would greatly reduce the amount of feed required while increasing the amount of salmon produced. There is currently concern over the regulation of this technology. In addition there is a large fear that if this GMO salmon escaped into the wild it would out compete wild populations and thus extinguish them.[12]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Great Barrier Reef Marine Park Authority. "Aquaculture Within the Great Barrier Reef Marine Park." Marine Pollution Bulletin 7.12 (2002): 10. Australian Government, 11 Apr. 2002. Web. 1 Apr. 2016. Web.
  2. 2.0 2.1 2.2 2.3 2.4 Lucas, John. "aquaculture." Current biology : CB 25.22 (2015): R1064-5. Web.
  3. "Fishing and Farming Methods" Monterey Bay Aquarium Seafood Watch. Web.
  4. Muir, James. "Managing to Harvest? Perspectives on the Potential of Aquaculture." Philosophical Transactions of the Royal Society B: Biological Sciences 360.1453 (2005): 191-218. Web.
  5. 5.0 5.1 5.2 Pomeroy, Robert S., John E. Parks, and Cristina M. Balboa. "Farming the Reef: Is Aquaculture a Solution for Reducing Fishing Pressure on Coral Reefs?" Marine Policy 30.2 (2006): 111-30. Web.
  6. Daw, T.; Adger, W.N.; Brown, K.; Badjeck, M.-C. 2009. "Climate change and capture fisheries: potential impacts, adaptation and mitigation." Climate change implications for fisheries and aquaculture: overview of current scientific knowledge. FAO Fisheries and Aquaculture Technical Paper. No. 530. Rome, FAO. (2009): 107-150. Web.
  7. Urban fish farms a wave of the future?; A new york educator says big- city aquaculture can ease overfishing, add jobs and improve diets. (2006, Aug 14). Los Angeles Times
  8. e-Jahan, Khondker Murshed, Mahfuzuddin Ahmed, and Ben Belton. "The Impacts of Aquaculture Development on Food Security: Lessons from Bangladesh." Aquaculture Research 41.4 (2010): 481-95. Web.
  9. National Oceanic and Atmospheric Administration. "Fisheries." NOAA's Coral Reef Conservation Program. US Department of Commerce, 13 July 2015. Web. 01 Mar. 2016. Web.
  10. "Impact of Fish Aquaculture Effluent on Reef-Associated Microbial Communities & Coral Health." Fish Effluent Impact on Reef Microbes & Coral Health. Coral Reef Target Research & Capacity Building for Management, 2013. Web. 02 Mar. 2016. Web.
  11. "Impact of Fish Aquaculture Effluent on Reef-Associated Microbial Communities & Coral Health." Fish Effluent Impact on Reef Microbes & Coral Health. Coral Reef Target Research & Capacity Building for Management, 2013. Web. 02 Mar. 2016. Web.
  12. 12.0 12.1 Rack, Jessie. "Genetically Modified Salmon: Coming To a River Near You?" NPR The Salt (2015): Web