If you’re thinking of starting a pond in your home for decorative purposes, consider aquaponics as…
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Aquaponics systems commonly involve raising freshwater fish because they can tolerate diverse water temperatures and pH levels. However, saltwater aquaponics or marine aquaponics exists as a branch of regular aquaponics systems where breeders raise saltwater fish. Research surrounding saline-based aquaponics systems is ongoing, with only a handful of tangible examples to support the culture. Still, the benefits and drawbacks of this system remain the same in theory.
Saltwater aquaponics is a way to utilize naturally existing saltwater by growing saltwater vegetation and saltwater fish in a controlled environment. One major drawback of the system is that it may not be the most feasible ecosystem for places where saltwater is not readily available. In this article, we discuss the benefits and drawbacks of a saltwater aquaponics system and touch a bit on its history.
Saltwater Aquaponics Benefits
Aquaponics systems are potentially profitable despite the current unavailability of reliable economic data on the subject. By translating a common freshwater system into one that utilizes salt water, you may seize the opportunity to use salt water in ways that standard aquaponics create a sustainable environment for fish and plants.
As a general overview of standard aquaponics, this system combines aquaculture and hydroponics. Aquaculture is the practice of raising aquatic animals, usually freshwater fish. Meanwhile, hydroponics involves cultivating plants in water instead of soil.
The idea behind aquaponics is to utilize the nitrogen cycle. Fish excrete waste that contains the nutrients that plants need to grow. At the same time, the plants clean the water that would otherwise be poisonous to the fish if their waste remains unprocessed.
A saltwater aquaculture system adopts the same concepts for raising saltwater fish and growing plants that can tolerate certain salinity levels. Saltwater already has aquatic waste that can provide plants’ nutrients for growth. Simultaneously, the plants would filter the saltwater just enough for the fish to live without risking disease from unclean saltwater.
If you are building a saltwater aquaculture system in a fishery, you get to conserve land space. Standard aquaponics systems are closed environments, which you would have to build facilities around to maintain an optimal atmosphere for the fish and plants. Saltwater systems still needs facilities, but with existing fisheries, you can integrate the system with the saltwater vegetation you intend to grow.
Saltwater Aquaponics Drawbacks
Saline-based aquaponics systems would require a steady source of saltwater to maintain. If you live near the sea, you would need specialized pumps to bring the saltwater into your aquaponics system. These machines can be costly — even more so if you live in a place where saltwater is not readily available.
Pumping saltwater into your aquaponics systems may also alter the water conditions before the saltwater gets to your system. Even without pumps transporting the water to your aquaponics system, soil irrigation and land clearing alter the saltwater quality, thus changing water temperature levels.
With inconsistent saltwater temperature and quality levels, maintaining an effective saline-based system requires more effort than a standard freshwater aquaponics system. The saltwater’s variability also limits the kinds of fish and plants you can raise and cultivate.
Commercial saltwater systems raise shrimp, prawns, sea urchins, clams, oysters, mollusks, crustaceans, abalone, pufferfish, and sea finfish species. Common salt-tolerant plants or halophytes that hydroponic systems cultivate include seaweed, algae, plankton, Swiss chard, and New Zealand spinach.
Saltwater conditions must be compatible with saltwater fish and plants that can thrive in certain salinity levels. Slight differences may cause an imbalance in your aquaponics system, thus affecting your fish and plant growth rate.
History of Saltwater Aquaponics
Many fisheries already utilize open circulation practices in raising their fish. These systems are common in coastal zones where saltwater has high concentrations of soluble nitrogen from aquatic waste. Uncontrolled amounts of aquatic waste are harmful to the environment, prompting experts to develop closed saltwater systems.
Marine aquaculture dominates freshwater aquaculture in Japan, making the use of saltwater in aquaponics a popular concept in the country. There are two current examples of Japanese companies that utilized saltwater to create a sustainable recirculating system.
Azuma-Cho Fishery Cooperative bred seaweed near saltwater aquaculture farms in 2000 in an effort to create and maintain their aquaponics system. IMT Engineering, Inc. also conducted aquaponics experiments from 2003 to 2005, where they grew watercress and water spinach using wastewater from shrimp cultures.
A team of experts from the Yangzhou University in China under Professor Liu Shiping’s leadership successfully created rice varieties that can grow in saltwater. Their studies yielded between 6.5 and 9.3 tons of rice per hectare.
Florida-based Mote Aquaculture Park has a sustainable fish farming facility where they distribute fish and plant productions to local wholesalers. They raise red drum fish and cultivate with saltwort and sea purslane. In 2014, the facility demonstrated saltwater-based aquaponics practices with the goal of the eventual adoption of such practices.
Saltwater aquaponics substitutes common freshwater aquaponics systems with a saline water system to raise saltwater fish and cultivate salt-tolerant plants. These aquaponics systems offer the regular benefits of standard aquaponics systems where you have fish excrete waste to provide plant sustenance, while the plants filter the harmful components of fish waste when left alone.
Despite this benefit, using saltwater in aquaponics may not be the best system to adopt if you live in an area without a ready supply of saltwater. Saltwater setups can also be limited by the variety of fish and plants you can raise and cultivate for commercial or personal reasons.