Evaluating the Viability of Raising Pacific White Shrimp (Litopenaeus vannamei) Aquaponically in Freshwater

Commodities

Practices

The proposed solution to the problem is to integrate the cultivation of high value marine species in a freshwater aquaponic system. Pacific White Shrimp are a species that can adapt to different salinity at various stages of their development, making them well-suited for cultivation in inland production systems with no access to sea water. Numerous studies have been conducted to evaluate the potential of growing this species in brackish/freshwater environments, and most of these studies have concluded that successful cultivation can be achieved when specific water conditions are met. 

One significant advantage of cultivating Pacific White Shrimp in controlled, indoor environments is their rapid growth rate. Unlike other commonly farmed freshwater fish species like Tilapia, which can take a year or more to reach market size, Pacific White Shrimp can reach market size in approximately 4 months or less. This shorter growth period allows for multiple grow cycles of shrimp within a year, resulting in increased cash flow for aquaponic growers. In comparison, growers relying solely on Tilapia would have to wait much longer to generate the same level of income. 

Furthermore, the market demand and price for Pacific White Shrimp is generally higher than that of Tilapia. A quick search on Wholefoods' website reveals that Pacific White Shrimp is priced at $12.99 per pound, while Tilapia fillets are priced at $8.99 per pound. This price difference highlights the potential for higher profitability when cultivating Pacific White Shrimp versus Tilapia. According to seafoodsource.com, the US imported 152 million pounds of shrimp in the month of July 2023.  By introducing a high-demand product like Pacific White Shrimp, which sells well across various demographics, we aim to enhance the economic viability of aquaponics systems. 

This project will evaluate shrimp and plant growth at varying salinities to determine if a suitable level can be achieved in a shared environment where both shrimp and plant flourish.  While Pacific White Shrimp can accommodate a wide range of salinities, most aquaculturist rear this species between 28ppt and 32ppt.  During this experiment, we will be going as low as 2ppt.  Most agricultural land crops do not tolerate excessive sodium in their growing environment and while some are more sensitive than others, this experiment will focus on one of the more sensitive crops, strawberries.

Two experiments in triplicate will explore four groups of shrimp cultivated at salinities of 2ppt, 5ppt, 10ppt and 32ppt as the control. Experiment 1 will evaluate each group using a commercially available aquarium salt, Red Sea (RS) or Instant Ocean (IO). Experiment 2 will repeat the same procedures as experiment 1 but will replace the commercial salt with a DIY low cost salt.  Each test group will consist of 50 shrimp per 100 gallon container along with four (4) Everbearing Ozark or Albion bare root strawberries grown aquaponically, indoors, under grow lights.  Water will be obtained from municipal sources and treated with Sodium Thiosulfate to eliminate chlorine/chloride toxicity. Salinity levels will commence at 32ppt for all groups. Duration: During the first year, three iterations of the experiment 1 will be run using commercial salt mix (RS or IO). Each experiment will last 120 days. We expect challenges during the winter months with respect to growth and survival if water and indoor temps cannot be maintained at optimal levels. Year two will replicate the three iterations but will replace the commercial salt with a low cost DIY salt consisting of food grade minerals.  Feed: Commercial feed specifically formulated for Pacific White Shrimp will be purchased from Ziegler Bros. at sizes appropriate for each developmental stage. Feed will be administered by hand 3 times daily to satiation.

Tank Setup: 100 gallon containers fitted with lids will be used as the aquaculture tanks. Heat mats will be placed under each tank to provide radiant heat. Two air stones will be placed in each tank to deliver diffused oxygen. Oxygen will be supplied by a dedicated air pump for each tank in order to eliminate a single point of failure. Filtration: Dedicated canister filters will be used for each tank and solids (uneaten feed and feces) will be siphoned from the bottom of the tanks 2 times daily.

Shrimp: Pacific White Shrimp (L. Vannamei) will be obtained from American Penaeid, a nursery in Florida. Average age to be supplied will typically be around 8-12 days old (PL8 - PL12). Upon arrival, PL will be acclimated to commercial or DIY salt water at the salinity closest to shipment water (~32ppt). Acclimation to desired experimental salinities will not begin until 7-8 days post arrival to ensure all PL are at least 15 days old (PL15). Acclimation: Each group will receive freshwater drip acclimation at a rate of 50% reduction over a period of 48hrs. So for example, the initial salinity of 32ppt will be reduced to 16ppt over 48 hours. Subsequently, 16ppt to 8ppt over 48 hours etc, until desired salinity is reached for each group. Depending on how the shrimp are responding, a 24 rest period may be imposed between reduction acclimation iterations.

Strawberries: Bare-root strawberries will be obtained from Amazon or an online nursery. Roots will be placed directly into shrimp tanks once desired salinity is achieved. If it appears the shrimp are feeding on the roots, plants will be moved to a separate container and culture water will be pumped to plants.

Water management and monitoring will be a key area of focus to ensure that water quality remains optimal for this unique environment. Parameters such as salinity, pH, temperature, dissolved oxygen, ammonia, nitrate, calcium, potassium, magnesium, alkalinity, and hardness will be closely monitored. Regular testing of these parameters will be essential to maintain the balance of the system and ensure the well-being of both the shrimp and strawberries. Success may hinge on the ability to maintain specific ionic ratios of sodium to potassium and calcium to magnesium for the shrimp.  Adjustments of these minerals via supplementation of food-grade mineral salts may be required periodically throughout the experiment.

Monitoring: A combination of electronic meters, chemical reactions and optical devices will be utilized to test for salinity, ammonia, ph, temperature, dissolved oxygen, alkalinity, hardness, nitrate, and nitrite. Ions: Sodium, Calcium, Potassium, and Magnesium levels/ratios will be checked with specialized probes throughout each experiment . Data collection will focus on shrimp survival and growth along with monitored water parameters and strawberry leaf health/fruit production.