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On the Cover Images from left to right Methane flame generated from waste captured by RAS. Photo courtesy of Dr. Yonathan Zohar at UMBI Center Of Marine Biotechnology Lettuce and other vegetables growing in RAS aquaponic tanks at UVI. Photo courtesy of Dr. James Rakocy at the University of the Virgin in St. Croix. produced in a RAS facility at Blue Ridge . Photo courtesy of Mr. Martin Gardner from Blue Ridge Aquaculture in Martinsville, VA. Nile , a often produced in RAS. RAS tanks for raising tilapia. Photo courtesy of Dr. Martin Schreibman at Brooklyn College, CUNY, Aquatic Research Environmental ssessment Center (AREAC)

This report is a joint project of the Alliance for Sustainable Aquaculture and & Watch.

About the Alliance for Sustainable Aquaculture Alliance for Sustainable Aquaculture (ASA) is a collaborative group of researchers, business owners, non-profit organizations and interested members of the public working to further Recirculating Aquaculture Systems (RAS) in the through research, education, legislative work and advocacy. We believe that RAS, closed-looped and biosecure aquaculture operations, are the best option to meet our country’s need for a clean, green, sustainable, healthy source to supplement our wild .

1616 P St. NW, Suite 300 Washington, DC 20036 tel: (202) 683-2500 fax: (202) 683-2501 [email protected] www.foodandwaterwatch.org/asa

About Food & Water Watch Food & Water Watch is a nonprofit consumer organization that works to ensure clean water and safe food. We chal- lenge the corporate control and abuse of our food and water resources by empowering people to take action and by transforming the public consciousness about what we eat and drink. Food & Water Watch works with grassroots or- ganizations around the world to create an economically and environmentally viable future. Through research, public and policymaker education, media and lobbying, we advocate policies that guarantee safe, wholesome food produced in a humane and sustainable manner, and public, rather than private, control of water resources including , and groundwater.

Main Office Office 1616 P St. NW, Suite 300 25 Stillman Street, Suite 200 Washington, DC 20036 San Francisco, CA 94107 tel: (202) 683-2500 tel: (415) 293-9900 fax: (202) 683-2501 fax: (415) 293-9908 [email protected] [email protected] www.foodandwaterwatch.org

Copyright © September 2009 by Food & Water Watch. All rights reserved. This report can be viewed or downloaded at www.foodandwaterwatch.org. Land-Based Recirculating Aquaculture Systems a more sustainable approach to aquaculture

Table of Contents iv Executive Summary

1 Introduction

1 What Is RAS?

2 Types of RAS: Freshwater and Saltwater

3 Why RAS Can Be an Important Production Method for the United States

4 RAS Factors

8 Research and Development

10 Future Improvements

12 Specific Commercial Case Studies

13 Conclusion

14 Endnotes Executive Summary This report, Land-Based Recirculating Aquaculture Systems, provides an introduction to Recirculating Aquaculture Systems (RAS). RAS are closed-loop facilities that retain and treat water within the systems. This form of land-based aquaculture is quickly gaining popularity in the United States. Land-Based Recirculating Aquaculture Systems addresses why RAS could be an important method of producing more fish for the United States; highlights research, development and technical innovations in RAS; and discusses concerns and recommendations for the future of these systems. Land-Based Recirculating Aquaculture Systems also provides commercial case studies of existing successful RAS operations in the United States.

Consumer demand for cleaner, greener, safer seafood is on the rise. Many popular fish, like , and certain snapper are depleted in the wild from many years of poor management, and other ecological problems like and damage to key areas. There is a need to supplement wild-caught fish to meet consumer demand for seafood. One method to produce more fish is known broadly as aquaculture — the rearing of aquatic in captivity. Aquaculture is also often called “fish farming,” as it can be likened to the farming of other food animals, like chickens, pigs and cattle. Aquaculture is increasing worldwide; between 2004 and 2006 the annual growth rate of this industry was 6.1 percent in volume and 11 percent in value.

Widespread open-water fish farming methods, such as coastal and open- aquaculture (OOA), can seri- ously damage marine and are far from providing the safe and many consumers want. In particular, OOA — the mass production of fish in huge floating net pens or cages in open ocean — raises concerns about consumer safety, pollution of the marine environment and conflicts with other ocean uses.

Fortunately, RAS can likely provide a cleaner, greener, safer alternative to open-water farms that does not compete with other ocean uses. These systems are usually land-based and reuse virtually all of the water initially put into the system. As a result, RAS can reduce the discharge of waste and the need for antibiotics or chemicals used to combat disease and fish and parasite escapes — all serious concerns raised with open-water aquaculture.

RAS provide a diversity of production options. Tilapia, , black seabass, , shrimp, clams and are just a few examples of what can be raised in these systems. RAS can also be operated in tandem with — the practice of growing plants using water rather than soil — to produce a variety of herbs, fruits and vegetables such as basil, okra, lettuce, tomatoes and melons. RAS range from small-scale urban aquaculture systems in individual homes to larger, commercial-scale farms that can produce fish and produce equaling millions of dollars in sales each year.

Currently, research and development is being conducted at academic, government and business facilities across the country to continuously improve the techniques and methods used in RAS. With innovations in waste management systems, fish feeds and energy usage, RAS has the potential to be a truly safe and sustainable aquaculture industry.

In recent years, the U.S. government has been shockingly insistent that development of open-water aquaculture, in particular ocean aquaculture, is the best way to have an increased seafood supply in the United States. Given the many ecological concerns associated with OOA, rather, the United States should be looking to explore more sus- tainable fish production, such as RAS. This report challenges managers and consumers to be more active in helping to promote a cleaner, greener, safer domestic seafood supply by learning more about RAS and re- questing grocery stores and restaurants carry RAS products rather than those from open-water aquaculture systems. Alliance for Sustainable Aquaculture and Food & Water Watch

Lettuce and other vegetables growing in RAS aquaponic tanks at UVI. Photo courtesy of Dr. James Rakocy at the University of the Virgin Islands in St. Croix. Introduction onsumer demand for cleaner, greener, safer seafood is on the rise. Popular species Cof wild fish are depleted,1 leaving many people looking to aquaculture to help meet the demand for seafood. Aquaculture production — the rearing of aquatic plants and animals in captivity — is increasing worldwide; between 2004 and 2006 the annual growth rate was 6.1 percent in volume and 11 percent in value.2 There are many forms of aquaculture; recirculating aquaculture systems (RAS), coastal ponds and open- water net pens are a few major types. Open-water aquaculture systems are, as they sound, open to air and water, and can therefore have a risk of air- or water-borne contaminants.3 RAS are closed, controlled, bio-secure systems that retain and treat water within the system, reducing the risk of contamination from air- and water-borne contaminants. What Is RAS?

Recirculating aquaculture systems (RAS) are closed- Various methods can be used to clean the water from the loop facilities that retain and treat the water within the fish tanks and make it reusable. Some RAS fish farms system. The water in RAS flows from a fish tank through incorporate aquaponics — the practice of growing herbs a treatment process and is then returned to the tank, and vegetables in water — into their system. Plants need 4 hence the term recirculating aquaculture systems. RAS 13 elements to grow; the wastewater from the fish tanks can be designed to be very environmentally sustainable, naturally provides 10 of these elements.7 The plants using 90-99 percent less water than other aquaculture thrive in the -rich system water, and they actu- 5 systems. RAS can reduce the discharge of waste, the ally help to purify it for reuse — the plants absorb the need for antibiotics or chemicals used to combat disease, and the “cleaned” water can go back to the fish and fish and parasite escapes. RAS have been under tanks! development for the over 30 years, refining techniques and methods to increase production, profitability and environmental sustainability.6

1 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture

An example of a small-scale RAS. Types of RAS: Freshwater and Photo by Eileen Flynn Saltwater the prevalence of carbon dioxide within these systems Recirculating aquaculture systems can be divided into and provide a food source to developing fish. two main categories: freshwater and saltwater opera- tions. Each of these can be paired with specific technolo- Saltwater RAS gies designed to maximize efficiency within the system, minimize effluent discharge and occasionally to work in Saltwater RAS can take several forms as well, and are a symbiotic relationship with other technologies, re- sometimes referred to as marine RAS. One type of sys- viewed in brief below. tem that has been researched extensively in recent years is the high-rate algal , or HRAP. HRAPs make use of macroalgae — — in order to reduce the Freshwater RAS amount of waste in RAS. In fully recirculating systems, Freshwater RAS can include the production of such nitrate and phosphate levels accumulate at a rate that is fish as tilapia, catfish, or striped bass, among oth- proportional to fish density; thus, the larger the produc- ers. One innovative method explored in conjunction tion scale, the more effluents will appear in the system with freshwater RAS is aquaponics, as described above. and need treatment in order to ensure the continued Aquaponics works by allowing for the growth of plants, growth of the fish.10 Macroalgae can accomplish this be- fish and nitrifying bacteria simultaneously — each of cause they absorb the nutrients that are in fish waste for which feed off of the waste of the others to create a sys- their own growth, the same way that aquaponics produce tem that requires very little maintenance, aside from pH plant growth from these nutrients. The difference in ma- monitoring, to ensure optimal growth.8 A major concern rine RAS is that the seaweed is generally not intended for of most aquaculture systems is the buildup of ammonia consumption, and the seaweed will thrive in high-salin-

(NH3) and its derivatives from fish waste, which can be ity environments, whereas land-based plants would not. fatal to fish even at very small concentrations — as little Macroalgae HRAPs have been found to be even more as .08 mg/L. Aquaponic systems work by introducing productive in the removal of wastes than the microalgae nitrifying bacteria, which feed on the ammonia in fish that are used in freshwater systems, so this is considered waste to convert it into nitrate, which is non-toxic to the a very viable route for marine RAS.11 One factor that is fish and beneficial for the plants.9 Another innovation in holding back more extensive use of the HRAP system is freshwater RAS involves the use of microalgae to reduce that seasonality can affect the of micro- and

2 Alliance for Sustainable Aquaculture and Food & Water Watch macroalgae alike — with higher productivity rates in the Water Reuse warmer, brighter summer months. RAS are completely contained systems that reuse most of the water from the fish holding tanks. Wastes are Why RAS Could Be an Important Fish removed; water is treated and then recycled back to the Production Method for the United tanks. Ideally, RAS only replace very small percentages of the total water volume, due to some loss during waste States removal and/or evaporation (less than 1 percent daily water exchange).14 This low replacement volume is espe- How RAS Function cially important in saltwater systems since salt water can A key feature of RAS is that it re-uses water; the water is be more expensive and more difficult to make or obtain recirculated continuously throughout the system. All of than . the tanks and various components in RAS are connected by pipes. Water flows from the fish tank to the mechani- Space and Production Efficiency cal filter where solid waste is removed. The water then RAS production levels are often higher than those in oth- flows into a biological filter that converts ammonia to er forms of aquaculture. RAS control the environmental nitrate. Some RAS incorporate plant tanks as a biologi- conditions in which products are raised, thus allowing cal filter – plants absorb nutrients, thus “cleaning” the for optimal year-round growth.16 Some RAS can produce water. Other systems use special tanks that are designed market-sized fish in just nine months, compared to the to promote good bacteria growth – the bacteria act as 15 to 18 months it often takes for the fish raised in other a filter. After being “treated” in the mechanical and biofiltration components, the water flows back to the fish tank. Open-Water Aquaculture Biosecurity Open-water aquaculture, (when in the ocean, also known as , ocean fish farming, open-ocean RAS fish farms are often fully closed and entirely con- aquaculture and other, similar terms), is the mass production of trolled, making them mostly biosecure — diseases and fish in coastal ponds, or large floating pens or cages in ocean parasites cannot often get in. Biosecurity means RAS waters. Just one farm is a large-scale operation. can frequently operate without any chemicals, drugs or antibiotics, making a more natural product for consum- While open-water fish farming is a fairly common practice ers. Water supply is a regular route of pathogen entry, worldwide (we don’t do it large-scale in U.S. waters currently) it so RAS water is often first disinfected or the water is can pose real threats to health and the environment: obtained from a source that does not contain fish or in- • Fragile habitat can be permanently damaged from clearing vertebrates that could be pathogen carriers (rain, spring out space to site the farm or from anchors to hold down or well water are common sources).12 Biosecurity in RAS cages. requires that the systems be designed for easy clean- ing, completely and frequently, to reduce pathogens.13 • Fish in cages can spread diseases to wild fish, or escape Being self-contained and cleaner also means RAS can be and intermix with wild fish, interfering with or even located near markets or within land-locked communi- overtaking natural populations. ties that will use the fish, rather than by natural water • Open-water fish farms allow free flow of water between sources like oceans or rivers — RAS does not need to be the fish enclosures and the ocean. Concentrated amounts located on water to supply the system or for drainage. of fish food, wastes, diseases and any chemicals or Locating RAS by the markets or communities they serve antibiotics that may be used in farms can flow straight into means they can have a smaller carbon footprint due to open waters, polluting habitat and wildlife and impeding reduced shipping distance and provide a fresher product recreational water uses like swimming and diving. to the consumer. • Chemicals used in production may remain in the fish and be transferred to people who consume them later.

Because there are so many potential problems with open-water farms, the United States should explore other options, like RAS.

3 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture systems to grow to market size.17 It takes 197.6 acres of their gills. The amount of DO that a fish needs to stay open ponds to produce the same amount of shrimp that alive and grow depends on the species and size of fish, a RAS farm can raise on just 6.1 acres.18 Tilapia, cobia, as well as the effects of the other water quality param- black bass, branzini, salmon, and shrimp are eters.21 A fish with a higher metabolic rate will consume among the many seafood products being raised in RAS. DO at a higher rate. 22 Oxygen is also critical to the meta- Aquaponic RAS produce a large array of herbs, vegeta- bolic processes of the bacteria living in the system that bles, fruits, flowering plants and as well. break down ammonia and solid waste.23

Low levels of DO in the system can reduce productivity RAS Factors of the fish and bacteria, ultimately resulting in mortali- ties. DO levels are monitored as water is leaving the Water Quality and Waste Management fish tank or the biological filter (where a large amount of The critical water quality parameters in RAS are dis- bacteria lives) to accurately access the level of DO that is solved oxygen, , pH, alkalinity, suspended available to fish and bacteria respectively.24 solids, ammonia, nitrite and carbon dioxide (CO2).19 These parameters are interrelated in a complex series of DO can be maintained in RAS through aeration, either physical, biological and chemical reactions.20 Monitoring with atmospheric oxygen (air) or pure oxygen. Standard and making adjustments in the system to keep the levels sources of air in aquaculture are blowers, air pumps or of these parameters within acceptable ranges is very compressors. The primary differences between these important to maintain the viability of the total system. options are the water and DO pressure requirements 25 The components that address these parameters can vary and volume discharged. Airstones, pieces of limewood from system to system. or porous rock, are often used to release the air into the water.26 Pure oxygen sources are used when diffusing atmospheric oxygen (air) into the system cannot keep Dissolved Oxygen up with the consumption of DO by the fish and bacte- Oxygen that is dissolved in the water is called dissolved ria. Three sources of pure oxygen often used for RAS oxygen or DO. Fish take in DO from the water through are high-pressure oxygen gas, liquid oxygen and on-site

Oxygen dissolving into a RAS. Photo by Eileen Flynn

4 Alliance for Sustainable Aquaculture and Food & Water Watch generators.27 U-tube aerators, packed columns, low head oxygenators and down-flow bubble contactors are component options for diffusing pure oxygen into the system water. These components are all designed to use a counter-flow of water and oxygen to enhance the gas- liquid interface forcing more oxygen to dissolve into the water.28 In general, warm-water fish grow best when DO concentrations are above 5 mg/L.29

Temperature Fish are cold-blooded; the temperature of the water in which they live controls their body temperature. Water temperature directly affects the physiological processes of fish such as respiration rate, efficiency of feeding and assimilation, growth, behavior and reproduction.30 Fish are often grouped into three categories based on pre- ferred temperature ranges: cold-water species below 60 degrees Fahrenheit, cool-water species between 60 F to 68 F and warm-water species above 68 F.31 To ensure maximum growth and minimize stress, need to be maintained in the species’ optimal range. Indoor RAS allows the farm to have greater control over the temperature of the ambient air that can impact the pH testers. water temperature. Heaters and chillers can be added to Photo by Eileen Flynn RAS to maintain temperature, though this is not ideal in concentrations of ammonia from fish wastes. When fish terms of energy efficiency. waste is produced, most of it eventually breaks down into nitrate, and nitrate accumulation tends to produce a At Skidaway Institute of , Dr. Richard Lee, drop in pH and alkalinity, which can be harmful to fish if an emeritus professor of oceanography, uses geothermal it is not monitored properly.34 chilling and solar heating to regulate the temperature of his RAS. The geothermal chilling is conducted through The scale of pH ranges from 0 to 14, with lower numbers a closed-loop pipe running down into the groundwa- demonstrating increased acidity and higher numbers ter and back up to the surface (no water is exchanged showing greater basicity. Seven is considered the equi- between the facility and the groundwater). The ground- librium point of freshwater, where it is neither acidic nor water is approximately 64.5 F and the contact of the cool basic. In freshwater RAS, pH is generally maintained water on the outside of the pipe transfers the heat so that around 6 to 7.5. In aquaponic systems, pH may be main- the tank can maintain its temperature between approxi- tained at a slightly lower level (around 5.5 to 6.5), where 32 mately 79 F and 82.5 F during a Georgia summer. The the slightly higher acidity level helps plants to obtain nu- solar heating is conducted by running pipes carrying trients. Some studies have been done in aquaponics sys- system water through sheets of black plastic that trans- tems to reconcile the lower optimal pH of plants with the fer the heat they absorb from the sun to the water in the higher optimal pH of fish, and it has been found that a pipes. Using this method the RAS system had tempera- pH as high as 7 can be maintained without reducing the tures between approximately 70 F and 77 F in the winter productivity of plants.35 Marine RAS needs to maintain when air temperature was not above 60 F in the same a slightly higher pH, as the average pH of ocean saltwa- 33 time period. ter is around 8, which makes it somewhat basic. People who work with recirculating systems need to monitor pH and Alkalinity pH carefully in order to keep levels within an accept- able range for health and growth of the fish. Some of Monitoring of the pH level is among the most im- the aforementioned technologies, such as high rate algal portant tasks in RAS. The pH is directly affected by ponds, can act as a counterbalance to the accumulation

5 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture of certain chemicals within an RAS and can help to bal- Waste Removal: Ammonia, Nitrite, ance pH levels naturally. Nitrate, Solid and Suspended Waste (Without Aquaponics) Alkalinity is a measure of the pH-buffering capacity One major benefit of RAS over other forms of aquacul- of water.36 The principle ions that contribute to alka- ture is the ability to capture, treat and/or utilize waste linity are carbonate (CO -) and bicarbonate (HCO -). 3 3 from the system. In general, solid wastes, including Supplements may be added to water to adjust the alka- feces and uneaten feed, are filtered and removed from linity. Alkalinity of fresh water ranges from less than the system. Once removed, these solids can be treated 5mg/L to more than 500mg/L and salt water is about or utilized in a secondary function (converted to energy, 120mg/L CaCO .37 3 and possibly even feed). Systems that do not effectively and quickly remove fish fecal matter, uneaten food and other solids from the water will never produce fish economically.38

Nitrogen is required in small amounts by fish for good health and growth. that is not utilized by fish becomes nitrogenous waste in the system and needs to be removed. There are several sources of nitrogenous waste including: feces, urine, excretions from gill dif- fusion, uneaten food and dead and dying fish.39 The decomposition of these nitrogenous compounds is par- ticularly important because of the toxicity of ammonia, nitrite and to some extent nitrate to fish.40 Ammonia + exists in two forms: non-ionized NH3 and ionized NH4 . Non-ionized ammonia is the most toxic form, due to its ability to move across cell membranes.41 An increase in pH, temperature or increases the propor- tion of the non-ionized form of ammonia.42 Nitrite is the intermediate product in the process of nitrification of ammonia to nitrate and is toxic because it affects the blood’s ability to carry oxygen.43 In RAS, effluent water is passed through a biofilter containing bacteria that converts ammonia to nitrite and finally to nitrate.44 This conversion from ammonia and nitrite to nitrate is called nitrification; the bacteria in this process require ample amounts of oxygen.45 Plants in an aquaponic system will act as the biofilter converting ammonia and nitrates. In RAS facilities without plants in the system (aquaponics), the biofiltration component consists of media with living beneficial bacteria that converts harmful ammonia and nitrite to nitrate. and bacteria floating in the can also convert ammonia to nitrate.46 Nitrate is the end product of nitrification and is the least toxic; it can be removed from the system by daily water changes or denitrification.47 Denitrification is the process of converting nitrate to nitrogen gas; the bacteria in this process do not require oxygen.48 Treatment processes for recycling water at the USDA ARS National Cold Water Marine Aquaculture Center, Franklin, ME. Photo courtesy of Dr. Steve Summerfelt of the Freshwater Institute, Shepherdstown, WV.

6 Alliance for Sustainable Aquaculture and Food & Water Watch

Basil grown in a RAS aquaponics tank at UVI. Photo by Eileen Flynn

Carbon dioxide which break down carbon dioxide and reformulate it into Dissolved carbon dioxide is another product that can lesser molecules. accumulate in high-density RAS. Large-scale RAS Another process for carbon dioxide elimination is called systems must supplement their tanks with pure oxygen aeration stripping, a process in which water is forced for a greater quantity of fish to be bred, but this results through a series of cascading “stripping columns” that in insufficient natural removal of the carbon dioxide expose the water to air and result in the release of dis- (CO ) that is then produced.49 (In lower-density systems, 2 solved CO into the atmosphere. Experiments have been oxygenation is generally unnecessary, as sufficient water 2 done to determine the optimal ratio of air to water as it exchange and aeration occurs to naturally balance levels cascades through the stripping columns, and for now, of both oxygen and CO .) 2 experiments suggest that higher ratios of air to water — implying a slower filtration process — improve the Excessive levels of CO2 can result in changes in pH towards acidification, which can be detrimental to fish efficiency of carbon dioxide stripping from a recirculat- 51 if the pH level drops too low. Various technologies have ing system. been tested to reduce the amount of carbon dioxide in Similar to aeration stripping, a third type of carbon the water of these high-density systems. One method of dioxide removal is performed by vacuum degassing, a addressing excessive carbon dioxide is the use of chemi- process that vents excessive gasses through a vacuum or cals, which can balance pH levels and thereby eliminate pump system. The process of carbon dioxide elimination the CO in RAS.50 Sodium hydroxide and sodium bicar- 2 is similar to the manner in which it is eliminated in the bonate are two chemicals commonly used in aquaculture aeration stripping process.52 for this purpose. Both function by increasing alkalinity in the water, resulting in a series of chemical reactions

7 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture

The overall waste-capture efficiency of a full RAS facility is conducting research on RAS he calls “urban aquacul- can be 100 percent.53 ture.” Dr. Schreibman is working with RAS of various sizes that can be run virtually anywhere, in warehouses, Researchers and industry experts are developing a vari- on brownfield sites or right in your own home, utilizing ety of resourceful ways to deal with the waste produced the hydroponic component of aquaponics to clean the by RAS fish farms, such as creating fertilizer for crops water. One aspect of his research involves “aeropon- and plants. Some RAS farms turn the waste into pellets ics,” in which plants are suspended above the tanks to create a feed ingredient for other fish or shrimp. Still and sprayed with system water every 10 to 15 minutes other RAS turn the waste into methane gas, which can be instead of being submerged in the water.55 This process used to help power generators. 54 reduces the horizontal space needed to run the system when compared to other aquaponic systems. “Urban Research and Development aquaculture” can be located in or near populated areas, so it can provide positive socio-economic benefits — like Currently, research and development is being conducted jobs — as well as fresh, safe seafood and produce to local at academic, government and business facilities across markets.56 the country to continuously improve the techniques and methods used in RAS to offer consumers cleaner, green- Larger-Scale Aquaponics er and safer products. Dr. James Rakocy, director of the University of the Virgin Islands Agricultural Experimental Station, con- Urban Aquaculture as a Community- ducts RAS aquaponic research in a large-scale system Based Option with plants growing on floating rafts. Foam rafts float on Dr. Martin Schreibman, founder and director of the the surface of large water-filled hydroponic tanks. Plants Aquatic Research and Environmental Assessment Center develop and expand atop the rafts, basked in sunlight, at the City University of New York’s Brooklyn College, while roots get maximum exposure to water by growing

This is an urban aquaculture/aquaponics system (it grows both fish and plants) in a small setting — in fact it is in a part of a classroom at Brooklyn College! Photo courtesy of Dr. Martin Schreibman at Brooklyn College, CUNY, Aquatic Research Environmental Assessment Center (AREAC)

8 Alliance for Sustainable Aquaculture and Food & Water Watch beneath. Raft tanks have no size limitations. A disad- vantage of raft culture — exposing the roots to zooplank- ton and snails that may grow in the tanks — is addressed through the addition of ornamental fish (tetras) and red ear sunfish to consume these pests.57 Additional research has been done refining waste management components and water quality needs for optimal plant and fish growth. Dr. Rakocy’s research shows the tech- nology UVI uses can be applied for an individual family subsistence or commercial scale, while conserving water and recycling nutrients. Researchers at the UVI facility grow tilapia and continue to experiment with basil, okra, lettuce, watermelon, mint, chives, tomatoes, cantaloupe, cucumber, flowers, squash, bok choy, collard greens and sorrel (a locally grown plant used in a popular drink) and other crops. The UVI commercial-scale aquaponic sys- tem can annually produce up to 35,570 pounds of tilapia and vegetables on 1/8 an acre of land.58

Various Species Grown in RAS The list of aquatic species being researched and grown in RAS is constantly broadening to include: oysters, blue , sea bream, branzini, cobia, red drum, black seabass, bivalves, soft , horseshoe crabs, assorted Fish feed pellets. , , nautilus, tilapia, , striped Photo by Eileen Flynn bass, salmon and assorted shrimp. Dr Richard Lee at Skidaway Institute of Oceanography has found a unique solution to raising carnivorous fish The list of plants that are grown in conjunction with without taking wild fish. At the Skidaway RAS facility Dr. these aquatic species is also growing rapidly, including: Lee grows black seabass to a market size of two pounds algae, seaweeds, basil, okra, lettuce, watermelon, mint, in one year by feeding them whole tank-raised tilapia. chives, tomatoes, cantaloupe, cucumber, flowers, squash, The feed conversion rate is five pounds of tilapia to one bok choy, collard greens, sorrel, arugula, peas and vari- pound of black seabass. The seabass grow twice as fast ous pharmaceutical plants when they are fed tilapia, when compared to being fed the traditional fishmeal pellet. Feeding a tank-raised Fish Feed to a saltwater RAS raised fish also reduc- Existing RAS farms and researchers are working to feed es the chance of pathogen introduction. their fish a more environmentally sustainable diet while remaining nutritionally appropriate. One of the biggest A majority of commercial feeds use soybean as a com- and most crucial hurdles faced by aquaculture has been mon protein replacement for fishmeal and . There to decrease the amount of wild fish used as an ingredient are some concerns with using soybean, a terrestrial in fish feed. Traditionally, large amounts of wild fish are protein, in fish feed. In 2009, 91 percent of soybeans 60 used to produce the pellet feed for farmed fish. Taking grown in the United States were genetically modified. prey fish from the oceans to feed farmed fish can deplete Another concern is that soybeans are high in estrogen 61 ocean food chains and disrupt ecological balance. Work and do not occur naturally in the aquatic environment. is being done at various RAS farms to improve feed, In addition, soy protein is quite expensive. Many re- including reducing the amount of fish needed to be put searchers are looking to replace soybeans in feed with into feed; finding alternative feed ingredients (includ- other proteins that occur naturally in the aquatic en- ing worms and algae);59 and even using waste to create a vironment, like algae, that could increase the financial healthy feed source. sustainability of RAS.

9 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture

Future Improvements RAS is not yet perfect, but the benefits of a controlled, closed system with waste management should not be overlooked. Additional research is being done to devel- op new techniques and methods to continually improve RAS.

Chemical Usage Water supply is a common means of pathogen entry. Water for RAS is often disinfected, or obtained from a source that does not contain fish or invertebrates that could be pathogen carriers (rain, spring or well water are common sources).62 Biosecurity in RAS requires that the systems be designed to be cleaned easily, completely and frequently to reduce pathogens.63

When diseases do appear, a veterinarian and diagnos- tic laboratory should be involved in determining the specific disease and treatment, using chemicals that are approved for use in food fish production.64 Many RAS can operate without any chemicals, drugs or antibiotics, making a more natural product for consumers.65

Energy Usage RAS facilities require varying amounts of energy to run the machinery that moves the water through the system and treatment processes. Some producers using aqua- ponics and facilities raising shrimp may be able to use fewer pieces of machinery to run the systems therefore having reduced energy demands. Research is being Lettuce and other vegetables growing in RAS aquaponic tanks at UVI. Photo courtesy of Dr. James Rakocy at the University of the Virgin Islands in St. Croix. done by Dr. Timothy Pfeiffer at the U.S. Department of Agriculture’s Agricultural Research Service to de- where the RAS are located.68 Wind energy has also been termine the specific energy requirements for different tested as a means to power reverse-osmosis membrane aspects of the treatment processes and how to get the filtration, which separates purified water from a concen- most efficient water treatment with the least amount of trated “brine” of fish effluent, with some success.69 Many energy.66 Dr. Yonathan Zohar, Director at University of these technologies have been proven viable at a small- of Maryland Biotechnology Institute’s Center of Marine scale, and implementation on large-scale (high-density) Biotechnology (COMB), is using waste captured from RAS are ongoing. RAS to produce energy in the form of methane that can be fed straight into a generator.67 Dr. Zohar and researchers at COMB are also working to convert algae Feed Efficiency , produced in RAS, into bio-fuel. In the production of farm-raised fish, the feed plays a large role in determining sustainability and quality of Both freshwater and marine RAS have been the sub- farmed fish. Farmed fish are often fed wild , ject of experiments to enhance energy efficiency. such as , and , after being Implementing solar heating for the maintenance of processed into fishmeal or oil. These prey fish are a proper temperature within the fish basin has been found crucial part of the marine , serving as food for to reduce conventional energy requirements by 66 per- marine mammals, birds and large . Since cent to 87 percent, depending on the regional climate

10 Alliance for Sustainable Aquaculture and Food & Water Watch taking these fish from the oceans can disrupt food chains treatments. Other forms of aquaculture that allow water and ecosystem balance, feed conversion rate is always to flow freely in and out of the holding ponds or cages a concern with farm-raised fish. The ideal feed conver- can not control what chemicals and pollutants are being sion is one pound or less of wild fish to raise one pound carried with the water. Some RAS/aquaponic facilities of farmed fish. Although existing feed sources do not have been certified organic for the plants produced. always have completely efficient 1:1 conversion rates, RAS farms and scientists are conducting research and Not a , but Still a developing techniques that can improve feed quality and Healthy One reduce the need for wild fish. Examples of innovations in RAS feed efficiency include finding alternative feed To achieve economic viability, RAS farms run their sys- ingredients, such as worms and algae, improving feed tems with a higher density of fish per tank than would be quality by using algae to increase protein content and found in the wild. Density depends primarily on water 71 raising prey fish in RAS, instead of harvesting wild for- quality, fish species and size. Overcrowding of younger age fish, to feed larger predatory fish.70 fish is avoided to allow them optimal room to grow dur- ing their rapid growth stage.72 As fish grow they may be moved to reduce densities to maintain good water “Organic”? quality and to optimize fish health and growth until they Organic are produced under conditions in which reach market size. RAS fish farmers avoid keeping fish all inputs are controlled. RAS is the only method of at densities that can be detrimental to fish health; for ex- raising fish that can completely control the production ample, trout raised at high densities can develop eroded environment. Being a closed-loop system, RAS can fins.73 Researchers regularly experiment with densities to better ensure fish and plants are not being exposed to ensure optimum health and productivity. synthetic or , growth hormones, sewage sludge, antibiotics or any other artificial feed or

Algae growing in tubes in RAS at COMB facility. Photo courtesy of Dr. Yonathan Zohar at UMBI Center Of Marine Biotechnology

11 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture

Specific Commercial Case Studies Blue Ridge Aquaculture Blue Ridge Aquaculture, established in 1993, pro- Premier Organic Farms duces RAS tilapia at their headquarters in Martinsville, Premier Organic Farms combines organic growing prac- Virginia. The 80,000 square foot facility produces four tices in controlled ecological environments as the basis million pounds of tilapia a year. 85 An estimated 75,000 for their state-of-the-art, eco-friendly aquaponics farm- pounds of live tilapia are shipped to market each week ing operation, which can run anywhere in the world.74 from the facility, making Blue Ridge the world’s largest The company has done extensive research and develop- indoor producer of tilapia.86 Blue Ridge Aquaculture as- ment over the past three years on its design known as serts that its products are free of growth hormones, pes- the “Pod Growing Unit.”75 Premier raises tilapia in RAS ticides, antibiotics, and synthetic chemicals.87 According facilities that are linked to plant tanks producing but- to the company’s president, Bill Martin, Blue Ridge ter and Boston lettuce, herbs, peppers and tomatoes as Aquaculture is one of few tilapia farms that hand select its core products.76 Premier Tilapia is fed an all-natural, for desirable characteristics, rather than us- nutritionally balanced diet of organic grain and pro- ing hormones.88 tein.77 Premier Organic Farms does not use antibiotics or chemicals.78 Nor does it use hormones.79 Other farms Blue Ridge is partnering with feed production com- use certain hormones to convert female fish to males (to pany Marical and Virginia Tech to research low-salinity 89 avoid unintentional breeding in grow out tanks before technology and feed options for cobia in RAS. The the sex of each fish can be identified).80 Premier plans company hopes to research other marine species once to build commercial Pod Growing Units near strategic they have brought the cobia production up to commer- 90 markets across the United States over the next five years, cial levels. Blue Ridge is also partnering with Virginia with further expansion worldwide as demand dictates. Tech on a 30,000-square-foot RAS facility dedicated to 91 One “Pod” is predicted to produce $43 million in rev- shrimp production. The aim is to bring shrimp produc- 92 enue annually from all segments (tilapia and mixed tion up to 325 million pounds per year. In 2007, Blue organic produce).81 Ridge began a joint venture with aquaculture company West Virginia Aqua, to produce over 300,000 pounds of Premier’s growing system uses 80 percent less water and rainbow trout in RAS.93 than conventional agriculture.82 The company’s goals are to produce high quality, safe food while achieving a carbon neutral footprint.

Marvesta Shrimp Farms Marvesta Shrimp Farms, located in Hurlock, Maryland, is growing saltwater shrimp away from the . Water from the Atlantic is brought in and filtered down to below 50 microns and run through an filter (which removes unwanted bacteria, algae and ).83 Co-founder Scott Fritze says that the water is 100 per- cent recirculating and completely bio-secure, with no effluent and little waste. The nitrification system that they have in place now is entirely indoors and produces some feed for the shrimp within the tanks. The small amount of waste produced by the system is composed of undigested protein, and can be easily dried out and dis- posed of.84 Marvesta does not use antibiotics, hormones, pesticides or chemicals of any kind. Computer rendering of the 4,800 L/min water recirculating system at the Conservation Fund Freshwater Institute. Summerfelt, S.T., Sharrer, M.J., Hollis, J., Gleason, L.E., Summerfelt, S. R. 2004. Dissolved ozone destruction using ultraviolet irradiation in a recirculating salmonid culture system. 32, 209-224. Drawing courtesy of Marine Biotech Inc. (Beverly, MA).

12 Alliance for Sustainable Aquaculture and Food & Water Watch

Fish waste being distributed by a manure spreader Summerfelt, S.T. and B.J. Vinci. (2008). Better management practices for recirculating systems. Pages 389-426 in C.S. Tucker and J.A. Hargreaves (editors), Environmental Best Management Practices for Aquaculture. Blackwell Publishing: Ames, Iowa Conclusion

Consumers love seafood, and with wild de- in this report, are just a few examples of successful com- pleted, aquaculture is likely to be supplying increasing panies that are producing RAS seafood. amounts of fish for food. However, not all fish farming methods are equal. In order to ensure safer and more Technical innovations are essential for the continued sustainable seafood, consumers are more regularly ask- growth of the aquaculture sector. Instead of pushing ing about how their fish was produced before making OOA, which can damage the marine environment and seafood choices. Common forms of aquaculture, such may pose a threat to consumer health, the U.S. govern- as open-water systems, can pollute the marine environ- ment needs to play a vital role in promoting opportuni- ment with chemicals and waste, and may produce sea- ties to develop cleaner, greener, safer aquaculture in the food contaminated with pesticides and antibiotics. These United States, such as RAS. 95 are not acceptable factors for most consumers seeking greener, more healthful options. Recommendations RAS, on the other hand, are closed, controlled, bio- Federal and State governments should increase funding secure systems. Since RAS retain and treat water within to RAS researchers to help provide consumers with a the system, they reduce waste discharges and the need cleaner, greener, safer seafood aquaculture option. for chemicals and antibiotics. RAS can be efficient in production and space usage and can range from small- If standards must be set for an organic label for fish, RAS scale to commercial operations — growing a variety of raised fish should viewed as the only true option, due to different fish and plants. the controlled, closed-loop nature of RAS.

RAS are currently operating in the United States. In Consumers should ask grocery stores and restaurant fact, RAS have been under development for over 30 managers whether the seafood they sell comes from years, refining techniques and methods to increase pro- domestic RAS farms. If not, they should request U.S. duction, profitability and environmental sustainability. 94 RAS-produced seafood as an alternative to imported, Academic, government and business facilities across the open-water farmed fish. country are conducting research and further improving and expanding RAS. Premier Organic Farms, Marvesta Shrimp Farms and Blue Ridge Aquaculture, highlighted

13 Land-Based Recirculating Aquaculture: A More Sustainable Approach to Aquaculture

Endnotes

1 Fishwatch.gov 33 Lee, Richard. “Rapid growth of black sea bass Centropristis stria- 2 FAO Fisheries and Aquaculture Department, Food and ta in recirculating systems with geothermal cooling, solar heating, Agriculture Organization of the United Nations. “The State of tilapia diet and microbial mat/seaweed filter.” Clean, Green, World Fisheries and Aquaculture 2008” Rome, Italy. 2009 at 16. Sustainable Recirculating Aquaculture Summit. Washington 3 Timmons, M.B. and J.M. Ebeling. (2007) “Recirculating D.C.: hosted by Food and Water Watch. January 2009. Aquaculture.” Cayuga Aqua Ventures at 3. 34 Neori, Amir, et al, “Biogeochemical processes in intensive 4 Timmons at 30. zero-effluent marine fishculture with recirculating aerobic and anaerobic biofilters.” Journal of Experimental 5 Timmons at 6. and Ecology 349 (2007): 241. 6 Timmons at 1. 35 Tyson, et al, “Effect of Water pH on Yield,” 2019. 7 Rakocy, James. “The UVI Aquaponic System.” Clean, Green, 36 Timmons at 56. Sustainable Recirculating Aquaculture Summit. Washington D.C.: hosted by Food and Water Watch. January 2009. 37 Timmons at 57. 8 Tyson, R.V. et al, “Effect of Water pH on Yield and Nutritional 38 Timmons at 115. Status of Greenhouse Cucumber Grown in Recirculating 39 Timmons at 53. Hydroponics.” Journal of Plant Nutrition 31.11 (2008): 2019 40 Timmons at 275. 9 Ibid. 41 Timmons at 54. 10 Metaxa, E., et al, “High rate algal pond treatment for water reuse 42 Timmons at 54. in a marine fish recirculation system: Water purification and fish 43 Timmons at 55. health.” Aquaculture 252 (2005). 44 Timmons at 275. 11 Pagand, P. et al, “The use of high rate algal ponds for the treat- 45 Timmons at 277. ment of marine effluent from a recirculating fish rearing system.” 46 Timmons at 281-283. Aquaculture Research 31 (2000). 47 Timmons at 56. 12 Timmons at 621 48 Timmons at 275. 13 Timmons at 620. 49 Summerfelt, Steven T., et al., “Evaluation of full-scale carbon 14 Torsten, E.I. Wik, et al. “Integrated dynamic aquaculture and dioxide stripping columns in a coldwater recirculating system.” wastewater treatment modeling for recirculating aquaculture Aquacultural Engineering 28 (2003). systems.” Aquaculture. 287. 2009 at 361-370. 50 Summerfelt, Steven T., et al, “Oxygenation and carbon dioxide 16 Timmons at 7. control in water reuse systems.” Aquacultural Engineering 22 17 Zohar, Yonathan. “Environmentally compatible, recirculated (2000). marine aquaculture: addressing the critical issues.” Clean, Green, 51 Summerfelt, et al, “Evaluation of full-scale carbon dioxide strip- Sustainable Recirculating Aquaculture Summit. Washington ping columns,” 2003. D.C.: hosted by Food and Water Watch. January 2009. 52 Summerfelt, et al, “Oxygenation and carbon dioxide control,” 18 Conversion of information from hectares to acres by Food & 2000. Water Watch from: Moss, Shawn. “An integrated approach 53 Timmons at 10. to sustainable shrimp aquaculture in the U.S.” Clean, Green, Sustainable Recirculating Aquaculture Summit. Washington 54 Zohar, Yonathan. “Environmentally compatible, recirculated D.C.: hosted by Food and Water Watch. January 2009. Samocha, marine aquaculture: addressing the critical issues.” Clean, Green, Tzachi. “Overview of some sustainable, super-intensive micro- Sustainable Recirculating Aquaculture Summit. Washington bial biofloc-rich shrimp production systems used by Gulf Coast D.C.: hosted by Food and Water Watch. January 2009. Research Lab, Waddell Center and AgriLife Research 55 Schreibman, Martin. “Urban Aquaculture: The promises and Mariculture Lab.” Clean, Green, Sustainable Recirculating constraints.” Clean, Green, Sustainable Recirculating Aquaculture Aquaculture Summit. Washington D.C.: hosted by Food and Summit. Washington D.C.: hosted by Food and Water Watch. Water Watch. January 2009. January 2009. 19 Timmons at 39. 56 Schreibman, Martin. “Urban Aquaculture: The promises and 20 Timmons at 47. constraints.” Clean, Green, Sustainable Recirculating Aquaculture Summit. Washington D.C.: hosted by Food and Water Watch. 21 Timmons at 88. January 2009. 22 Timmons at 88. 57 Rakocy, James. “The UVI Aquaponic System.” Clean, Green, 23 Timmons at 90. Sustainable Recirculating Aquaculture Summit. Washington 24 Timmons at 89. D.C.: hosted by Food and Water Watch. January 2009. 25 Timmons at 412. 58 Food & Water Watch staff email exchange with Dr. James 26 Timmons at 413. Rakocy, University of the Virgin Islands. June 22 – September 7, 27 Timmons at 413. 2009. 28 Timmons at 413-426. 59 Steve Craig and other from the Summit 29 Timmons at 50. 60 Kidd, Karen. “Effects of Synthetic Estrogen on Aquatic 30 Timmons at 51. Population: A Whole Ecosystem Study,” Freshwater Institute, 31 Timmons at 51. Fisheries and Oceans . 32 Lee, Richard. “Rapid growth of black sea bass Centropristis stria- 61 “Adoption of Genetically Engineered Crops in the U.S.: Soybean ta in recirculating systems with geothermal cooling, solar heating, Varieties.” Data Set, Economic Research Service, United tilapia diet and microbial mat/seaweed filter.” Clean, Green, States Department of Agriculture. www.ers.usda.gov/Data/ Sustainable Recirculating Aquaculture Summit. Washington BiotechCrops/ExtentofAdoptionTable3.htm D.C.: hosted by Food and Water Watch. January 2009. 62 Timmons at 621

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63 Timmons at 620. 75 Bedwell, Susan. Personal email. Chief Financial Officer of 64 Timmons at 648-649. Premier Organic Farms, May 15, 2009. Email on file at Food & 65 “General Discussion.” Clean, Green, Sustainable Recirculating Water Watch. Aquaculture Summit. Washington D.C.: hosted by Food and 76 Ibid. Water Watch. January 2009. 77 Ibid. 66 Pfeiffer, Tim. “Utilization of Low-head Technology for Inland 78 Ibid. Marine Recirculating Aquaculture Systems.” Clean, Green, 79 Ibid. Sustainable Recirculating Aquaculture Summit. Washington 80 Ibid. D.C.: hosted by Food and Water Watch. January 2009. 81 Ibid. 67 Zohar, Yonathan. “Environmentally compatible, recirculated 82 Ibid. marine aquaculture: addressing the critical issues.” Clean, Green, Sustainable Recirculating Aquaculture Summit. Washington 83 “Process.” Marvesta Shrimp Farms. Accessed on May 2, 2009. D.C.: hosted by Food and Water Watch. January 2009. Available at: http://www.marvesta.com/process.php 68 Fuller, R.J., “Solar heating systems for recirculation aquaculture.” 84 Fritze, Scott. Personal Interview. Cofounder and owner of Aquacultural Engineering 36 (2007). Marvesta Shrimp Farms, March 28, 2008. 69 Qin, Gang., et al, “Aquaculture wastewater treatment and reuse 85 Gardner, Martin. Personal email. Director of Marketing at Blue by wind-drive reverse osmosis membrane technology: A pilot Ridge Aquaculture, May 22, 2009. Email on file at Food & Water study on Coconut , Hawaii.” Aquacultural Engineering 32 Watch.Nicholls, Walter. “Two sides to every tilapia.” Washington (2005). Post, August 8, 2007. 70 Lee, Richard. “Rapid growth of black sea bass Centropristis stria- 86 Ibid. ta in recirculating systems with geothermal cooling, solar heating, 87 “Tilapia.” BlueRidge Aquaculture. Accessed on May 13, tilapia diet and microbial mat/seaweed filter.” Clean, Green, 2009. Available at: www.blueridgeaquaculture.com/tilapia. Sustainable Recirculating Aquaculture Summit. Washington cfm“Tilapia.” Op. cit. D.C.: hosted by Food and Water Watch. January 2009. 88 Martin, Bill. Personal Interview. President of BlueRidge Craig, Steve. “Sustainable Aquafeeds for Cobia” Clean, Green, Aquaculture, March 26, 2008. On file at Food & Water Watch Sustainable Recirculating Aquaculture Summit. Washington 89 Gardner, Martin. Op cit. D.C.: hosted by Food and Water Watch. January 2009. 90 Gardner, Martin. Op cit. Clean, Green, Sustainable Recirculating Aquaculture Summit. 91 Gardner, Martin. Op cit. Washington D.C.: hosted by Food and Water Watch. January 92 Gardner, Martin. Op cit. 2009. 93 Gardner, Martin. Op cit. 71 Timmons at 85. 94 Timmons, M.B. and J.M. Ebeling. “Recirculating Aquaculture.” A 72 Timmons at 120. at 1. 73 Timmons at 120. 95 FAO Fisheries and Aquaculture Department, Food and 74 Susan Bedwell. “Premier Organic Farms.” Clean, Green, Agriculture Organization of the United Nations. “The State of Sustainable Recirculating Aquaculture Summit. Washington World Fisheries and Aquaculture 2008” Rome, Italy. 2009 at 161. D.C.: hosted by Food and Water Watch. January 2009.

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