Saltwater aquaponics

Last updated January 03, 2024

Saltwater aquaponics (also known as marine aquaponics) is a combination of plant cultivation and fish rearing (also called aquaculture), systems with similarities to standard aquaponics, except that it uses saltwater instead of the more commonly used freshwater. In some instances, this may be diluted saltwater. The concept is being researched as a sustainable way to eliminate the stresses that are put on local environments by conventional fish farming practices who expel wastewater into the coastal zones, all while creating complementary crops.

History of the Practice and Current State of Direction

Currently, many conventional fish farming practices take place in the coastal zones with open circulation. This places an enormous load of urine and soluble nitrogen (that the feed and waste from fish release) at high concentrations into the ecological region. This can have many environmentally deleterious effects. In response to this, alternative aquaculture developments are quickly arising- Namely, recirculating aquaculture systems. By creating a closed system, fish farming has given locational freedom to the practice allowing for more inland developments.^[1]^{[ predatory publisher ]}

In countries like Japan, saltwater species are much more popular than freshwater fish which has spurred much of the desire for saltwater aquaponics systems.^[2]

The mainstream system for fish cultivation has also been mono-aquaculture (only one kind of fish/organism). With this method, oxygen consumption by the cultured fish increases, and the load of carbon dioxide becomes heavier. In addition, nutrients, such as nitrogen and phosphates from feces or remaining fish feed, dissolve in the seawater, making it eutrophic. This causes red tides, fish pathologies, and oxygen deficiency in seawater, resulting in the mass mortality of fish, auto-pollution, etc.^[2]

In response poly-eco-aquaculture looks to create symbiosis by establishing seaweeds throughout the year to create an artificial sea forest around the cultured fish cages. The seaweed takes up nutrients, such as nitrogen and phosphate from fish feces and remaining feed and gives off oxygen. The seaweed also inhibits pathogenic bacteria and red tide organisms. Grown seaweeds will then be fed to fish and urchins.

Other organisms which can be produced in these systems include sea cucumber which can be grown in symbiosis with abalone in aquaculture net cages as well. Feces generated by the abalone are fed to sea cucumber. Scallops can also be cultured because they eat organic suspended substances, such as the remaining feed and fish feces.

Environmentally sound poly-eco-aquaculture enables the preservation of aquatic environments to be compatible with that of sustainable aquaculture. With this method, healthy fish can be cultured in purified water while productively recycling seaweed to feed the fish.^[2]

Parts

Plants

Edible halophytes that can be grown in hydroponic systems include New Zealand spinach, common ice plant, common glasswort, barley, rice, and swiss chard. Algae, seaweed and plankton may be grown as well, possibly in combination.^[2]

The relationship between salinity and optimal growth of halotolerant and halophilic plants varies by species. Therefore, it is important to evaluate and optimize cultivation methods by adjusting the salt content of the seawater and diluting wastewater when necessary according to each specific combination of organisms.^[3]

Common Ice Plant (Suaeda japonica Makino)

Common ice plant can gradually acclimate to saltwater. It is possible to farm it in 100% seawater and directly connect its cultivation system to an aquaculture system for a wide range of fish species.^[2]

Common ice plant is known to accumulate high levels of heavy metals when grown in soil. This new system enables the farming of safe-to-eat organic ice plant by removing it from this environment.^[2]

Barley (Hordeum spontaneum)

After selecting the most salt tolerant strains, the University of California at Davis was able to grow barley irrigated with pure seawater and obtained half the normal yield per acre.^[4]

The experiment was conducted at Bodega Bay, North of San Francisco, in a laboratory on the Pacific Ocean.^[2]

Rice (PSBRc50)

A team led by Liu Shiping, a professor of agriculture at Yangzhou University, created rice varieties that can be grown in salt water. They were able to achieve yields of 6.5 to 9.3 tons per hectare.^[5]

Fish / other aquatic creatures

Common creatures in commercial saltwater aquaponics operations include sea fin fish, crustaceans, mollusks, echinoderms, shrimp, prawns, oysters, clam, abalone, flatfishes, and puffer fish. Saltwater fish generally fetch a higher market price than freshwater fish which makes for an economic incentive over traditional aquaponics systems.^[6]

It was also found that half pearls could be grown in cultured giant abalone in 5 months after a pearl nucleus was inserted into them. The shells can also be used for mother of pearl work.^[2]

Biofilters

Phytoplankton, Zooplankton

Utilization of aquatic organisms like phytoplankton, zooplankton assist in carbon dioxide and oxygen circulation.^[2]

Seaweed

Seaweed species have the capacity to take in nitrogen and phosphate loads. They also fulfill the role of oxygen producers. However, it is difficult for seaweed to completely take in nitrogen and phosphate loads alone. Even the most efficient species of seaweed requires an area two and a half times that of the fish farm in order to take in the total loads. Just the same, it is considered important to cultivate effective seaweed for the eutrophication of each fish farm and improve the water quality.^[2]

Operation

Feed Source

Utilization of aquatic organisms (e.g., phytoplankton, zooplankton, and fish) are an important part of constructing natural food chains within closed ecological systems.^[6]

Construction of a Spirulina to fish food chain opens up the possibility of recirculating aquaculture systems in areas where there may be scarcity or absence of suitable feed resources.^[2]

Nutrients

There are large differences in the concentrations of phosphorus, potassium, and magnesium between freshwater and saltwater aquaponics. Potassium and magnesium are major elements in saltwater. Phosphorus is excreted by fish. Its concentration is relatively low in freshwater conditions but high in saltwater.^[6]

Disease and pest management

Although a closed environment has the ability to cultivate large disease outbreaks, it simultaneously reduces predation risks. Outbreaks are also easier to address in a closed environment.^[2]

Black Spot Disease

If calcium, and to a certain extent, magnesium, are lacking, fish may fail to develop a healthy carapace after molting. This can especially lead to “black spot disease,” where the animal develops melanized lesions over all of its body, for example, after injury such as scraping against the sides of the rearing facilities.^[2]

Risks

Fish farmers' lack of experience with this system can result in massive deaths. Inappropriate disinfection, mistakes in oxygen supply, mismanagement of fish seed, and poor estimation of nitrifying capacity, can force the faculties to shut down. Other problems include the lack of backups (i.e. power and materials) in case of emergencies.^[2]

Current examples

Azuma-cho Fisheries

In 2000, Azuma-cho Fisheries Co-operative Association employed seaweed breeding near marine aquaculture farms in an effort to create a safe and sustainable aquaculture recirculating system.^[2]

IMT Engineering Inc

From 2003 to 2005, IMT Engineering Inc. conducted aquaponics experiments using the wastewater from shrimp cultures at a facility located in Tsukuba City, Japan. The crops that were tested were water spinach and watercress. The experimental facility was conducted with a 1200-ton grow-out pool.^[2]

Mote Aquaculture Park

A sustainable fish farming facility in Sarasota, Florida called Mote Aquaculture Park launched a commercial demonstration project in fall 2014 with the purpose of demonstrating marine aquaponics farming practices. The project raises the saltwater fish species red drum alongside salt-loving halophyte plants, sea purslane and saltwort.. The plants are on a 2 month harvest cycle, and sold via local farmers’ markets. The fish production is on a 9-12 months harvest cycle. They are distributed through Florida-based wholesalers.

Notes

↑ Gunning, Daryl; Maguire, Julie; Burnell, Gavin (2016). "The Development of Sustainable Saltwater-Based Food Production Systems: A Review of Established and Novel Concepts". Water. 8 (12): 598. doi: 10.3390/w8120598 . hdl: 10468/3627 .
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Takeuchi, Toshio. Application of Recirculating Aquaculture Systems in Japan. Springer, 2017.
↑ Custódio, M.; Villasante, S.; Cremades, J.; Calado, R.; Lillebø, AI (2017). "Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges". Aquaculture Environment Interactions. 9: 445–460. doi: 10.3354/aei00244 .
↑ Vysotskaya, L.; Hedley, P. E.; Sharipova, G.; Veselov, D.; Kudoyarova, G.; Morris, J.; Jones, H. G. (2010). "Effect of salinity on water relations of wild barley plants differing in salt tolerance". AoB Plants. 2010: plq006. doi:10.1093/aobpla/plq006. PMC 3000697 . PMID 22476064.
↑ Kentish, Benjamin (24 October 2017). "Chinese scientists may have just found a new way to feed 200 million people". The Independent.
1 2 3 "New Findings from Marche Polytechnic University Update Understanding of Water Science and Technology (Evaluation of Dicentrarchus labrax Meats and the Vegetable Quality of Beta vulgaris var. cicla Farmed in Freshwater and Saltwater Aquaponic ...)". Ecology, Environment & Conservation. 13 January 2017. p. 1027. Gale A476776071.

Related Research Articles

Aquaculture, also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants. Aquaculture involves cultivating freshwater, brackish water and saltwater populations under controlled or semi-natural conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish. Mariculture, commonly known as marine farming, is aquaculture in seawater habitats and lagoons, as opposed to freshwater aquaculture. Pisciculture is a type of aquaculture that consists of fish farming to obtain fish products as food.

Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater and fresh water together, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root brak. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment.

Mariculture or marine farming is a specialized branch of aquaculture involving the cultivation of marine organisms for food and other animal products, in enclosed sections of the open ocean, fish farms built on littoral waters, or in artificial tanks, ponds or raceways which are filled with seawater. An example of the latter is the farming of marine fish, including finfish and shellfish like prawns, or oysters and seaweed in saltwater ponds. Non-food products produced by mariculture include: fish meal, nutrient agar, jewellery, and cosmetics.

Eutrophication is the "explosive growth of microorganisms, to the extent that dissolved oxygen is depleted". Other definitions emphasize the role of excessive nutrient supply: "excessive plant growth resulting from nutrient enrichment". and phosphorus. It has also been defined as "nutrient-induced increase in phytoplankton productivity".

Fish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environments. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species produced in fish farming are carp, catfish, salmon and tilapia.

Aquaponics is a food production system that couples aquaculture with hydroponics whereby the nutrient-rich aquaculture water is fed to hydroponically grown plants.

<span class="mw-page-title-main">Aquatic ecosystem</span> Ecosystem in a body of water

An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic ; lotic ; and wetlands.

<span class="mw-page-title-main">Fishkeeping</span> Practice of containing fish

Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, serving as a branch of agriculture.

Integrated multi-trophic aquaculture (IMTA) provides the byproducts, including waste, from one aquatic species as inputs for another. Farmers combine fed aquaculture with inorganic extractive and organic extractive aquaculture to create balanced systems for environment remediation (biomitigation), economic stability and social acceptability.

A raceway, also known as a flow-through system, is an artificial channel used in aquaculture to culture aquatic organisms. Raceway systems are among the earliest methods used for inland aquaculture. A raceway usually consists of rectangular basins or canals constructed of concrete and equipped with an inlet and outlet. A continuous water flow-through is maintained to provide the required level of water quality, which allows animals to be cultured at higher densities within the raceway.

<span class="mw-page-title-main">Brackish marsh</span> Marsh with brackish level of salinity

Brackish marshes develop from salt marshes where a significant freshwater influx dilutes the seawater to brackish levels of salinity. This commonly happens upstream from salt marshes by estuaries of coastal rivers or near the mouths of coastal rivers with heavy freshwater discharges in the conditions of low tidal ranges.

Aquaculture started to take off in New Zealand in the 1980s. It is dominated by mussels, oysters and salmon. In 2007, aquaculture generated about NZ$360 million in sales on an area of 7,700 hectares. $240 million was earned in exports.

Microponics, in agricultural practice, is a symbiotic integration of fish, plants, and micro-livestock within a semi-controlled environment, designed to enhance soil fertility and crop productivity. Coined by Gary Donaldson, an Australian urban farmer, in 2008, the term was used to describe his innovative concept of integrated backyard food production. It is important to note that while "microponics" had been previously used to refer to an obscure grafting method in hydroponics, Donaldson's application of the term was derived from the amalgamation of micro-livestock (micro-farming) and the cultivation of fish and plants, a practice commonly known as aquaponics.

Aquaculture in Australia is the country's fastest-growing primary industry, accounting for 34% of the total gross value of production of seafood. 10 species of fish are farmed in Australia, and production is dominated by southern bluefin tuna, Atlantic salmon and barramundi. Mud crabs have also been cultivated in Australia for many years, sometimes leading to over-exploitation. Traditionally, this aquaculture was limited to pearls, but since the early 1970s, there has been significant research and commercial development of other forms of aquaculture, including finfish, crustaceans, and molluscs.

<span class="mw-page-title-main">Aquaculture in Canada</span>

Aquaculture is the farming of fish, shellfish or aquatic plants in either fresh or saltwater, or both. The farmed animals or plants are cared for under a controlled environment to ensure optimum growth, success and profit. When they have reached an appropriate size, they are harvested, processed, and shipped to markets to be sold. Aquaculture is practiced all over the world and is extremely popular in countries such as China, where population is high and fish is a staple part of their everyday diet.

Sea sponge aquaculture is the process of farming sea sponges under controlled conditions. It has been conducted in the world's oceans for centuries using a number of aquaculture techniques. There are many factors such as light, salinity, pH, dissolved oxygen and the accumulation of waste products that influence the growth rate of sponges. The benefits of sea sponge aquaculture are realised as a result of its ease of establishment, minimum infrastructure requirements and the potential to be used as a source of income for populations living in developing countries. Sea sponges are produced on a commercial scale to be used as bath sponges or to extract biologically active compounds which are found in certain sponge species. Techniques such as the rope and mesh bag method are used to culture sponges independently or within an integrated multi-trophic aquaculture system setting. One of the only true sustainable sea sponges cultivated in the world occur in the region of Micronesia, with a number of growing and production methods used to ensure and maintain the continued sustainability of these farmed species.

<span class="mw-page-title-main">Aquaculture in South Korea</span>

South Korea is a major center of aquaculture production, and the world's third largest producer of farmed algae as of 2020.

Sea cucumber stocks have been overexploited in the wild, resulting in incentives to grow them by aquaculture. Aquaculture means the sea cucumbers are farmed in contained areas where they can be cultured in a controlled manner. In China, sea cucumbers are cultured, along with prawns and some fish species, in integrated multi-trophic systems. In these systems, the sea cucumbers feed on the waste and feces from the other species. In this manner, what would otherwise be polluting byproducts from the culture of the other species become a valuable resource that is turned into a marketable product.

Recirculating aquaculture systems (RAS) are used in home aquaria and for fish production where water exchange is limited and the use of biofiltration is required to reduce ammonia toxicity. Other types of filtration and environmental control are often also necessary to maintain clean water and provide a suitable habitat for fish. The main benefit of RAS is the ability to reduce the need for fresh, clean water while still maintaining a healthy environment for fish. To be operated economically commercial RAS must have high fish stocking densities, and many researchers are currently conducting studies to determine if RAS is a viable form of intensive aquaculture.

An anchialine system is a landlocked body of water with a subterranean connection to the ocean. Depending on its formation, these systems can exist in one of two primary forms: pools or caves. The primary differentiating characteristics between pools and caves is the availability of light; cave systems are generally aphotic while pools are euphotic. The difference in light availability has a large influence on the biology of a given system. Anchialine systems are a feature of coastal aquifers which are density stratified, with water near the surface being fresh or brackish, and saline water intruding from the coast at depth. Depending on the site, it is sometimes possible to access the deeper saline water directly in the anchialine pool, or sometimes it may be accessible by cave diving.

References

http://www.seaweedguy.com/2012/07/24/saltwater-aquaponics/
http://aquaponicsjournal.com/docs/articles/Seaweed-is-Common-Denominator.pdf
Nozzi, Valentina; Parisi, Giuliana; Di Crescenzo, Davide; Giordano, Mario; Carnevali, Oliana (2016). "Evaluation of Dicentrarchus labrax Meats and the Vegetable Quality of Beta vulgaris var. Cicla Farmed in Freshwater and Saltwater Aquaponic Systems". Water. 8 (10): 423. doi: 10.3390/w8100423 .^{[ predatory publisher ]}

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[1] Gunning, Daryl; Maguire, Julie; Burnell, Gavin (2016). "The Development of Sustainable Saltwater-Based Food Production Systems: A Review of Established and Novel Concepts". Water. 8 (12): 598. doi: 10.3390/w8120598 . hdl: 10468/3627 .

[Takeuchi_2017-2] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Takeuchi, Toshio. Application of Recirculating Aquaculture Systems in Japan. Springer, 2017.

[Custodio_2017-3] Custódio, M.; Villasante, S.; Cremades, J.; Calado, R.; Lillebø, AI (2017). "Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges". Aquaculture Environment Interactions. 9: 445–460. doi: 10.3354/aei00244 .

[4] Vysotskaya, L.; Hedley, P. E.; Sharipova, G.; Veselov, D.; Kudoyarova, G.; Morris, J.; Jones, H. G. (2010). "Effect of salinity on water relations of wild barley plants differing in salt tolerance". AoB Plants. 2010: plq006. doi:10.1093/aobpla/plq006. PMC 3000697 . PMID 22476064.

[Kentish_2017-5] Kentish, Benjamin (24 October 2017). "Chinese scientists may have just found a new way to feed 200 million people". The Independent.

[eec_2017-6] 1 2 3 "New Findings from Marche Polytechnic University Update Understanding of Water Science and Technology (Evaluation of Dicentrarchus labrax Meats and the Vegetable Quality of Beta vulgaris var. cicla Farmed in Freshwater and Saltwater Aquaponic ...)". Ecology, Environment & Conservation. 13 January 2017. p. 1027. Gale A476776071.

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