A More Cost Effective and Sustainable Raceway Design for Indoor Shrimp and Fish Production

View the project final report

Commodities

• Animals: shellfish

Practices

• Animal Production: aquaculture
• Education and Training: on-farm/ranch research
• Sustainable Communities: local and regional food systems

Something on many fish farmers’ minds is how to lower the cost of entry (and cost of expansion growth) in the aquaculture industry. Startup and operating costs are just too high for many to get off the ground, let alone make a profit in a reasonable time to expand. Though our experiment involved rearing shrimp indoors, it applies to any species of fish/crustacean grown on farms today that involves farming infrastructure in tanks/pools.

The two main questions we are trying to solve:

1. Is there a better large indoor tank structure that is more durable and professional than a swimming pool, less expensive and easily moveable than fiberglass tanks, less labor intensive and easily movable than a wood frame raceway? These 3 typical options all have issues that are a heavy burden individually, especially for the beginning farmers. See below the pros and cons of these 3 options and our metal frame design.

2. Is there a more efficient way to heat large bodies of water in the grow out tanks than through the air or through hydronic systems, two methods commonly used? See below the pros and cons of 3 options and our pool heater design.

Through this project, we have found that using adjustable metal frame tanks that can accommodate varied sizes/dimensions and be easily moved are worthy middle grounds for new farmers or expanding farmers. The metal frame tanks are more professional-looking and durable than swimming pools or wood-frame tanks with a slightly higher price tag. The metal frame tanks are less expensive and easier to move than set fiberglass tanks.

We have also found that using heat pumps to heat water directly does come with the benefit of a straightforward design to implement compared to hydronic heating, wood burning stove, and gas fired air heating. It also comes with a chilling aspect for those hot summers that other heating methods do not have. However, there are considerations to be made for all heating sources depending on energy costs and availability, and what species one is trying to raise, along with the climate one is building a fish farm in.

We were able to run experiments comparing the grow out of saltwater shrimp in hydronic heated, round swimming pools versus heat-pump heated, rectangular adjustable metal frame raceway. The results showed that both yielded successful, comparable harvests (high survival rates and growth rates).

Even though the energy costs of heating for the rectangular raceways were higher, we believe it is worth it due to ease of harvest and more professional looking setup for marketing purposes compared to the swimming pools. We have shared these observations with other farmers and researchers and so far, we have heard from a new Ohio tilapia farmer they are looking to implement our rectangular raceway design and Bowling Green State already implemented our heater design for aquaponic use. The added benefit of the heater having a chiller option is an easy decision in the summer months when water temperature spikes in their greenhouse.

At our farms and fellow farmers looking to get into the industry or expand soon, this project has already piqued the interest of many to consider using adjustable metal frame raceways and heating/chilling water directly with a heat-pump. Though we were unable to collect data seeing customer sentiment about buying shrimp produced in one way versus another, the thought is the more professional the setup and further away from looking like swimming pools, the better. Especially for a higher priced seafood product.

Metal Frame Raceway Design Drawing

The raceway system will be built out at one of the OceanArc locations in central Ohio and also at the Green Valley Shrimp Farm facility to produce saltwater shrimp indoors. The raceway will measure 10FT W x 40FT L x 3FT H, divided into moveable powder-coated metal panels that are 3FT W x 10FT L each. 10 of these panels bolt together using bolts and screws to build the tank frame which will sit on the concrete floor. This raceway will hold 9,000 gallons of water, effectively replacing the footprint of (3) 14FT DIA swimming pools currently used in most OceanArc facilities.

This system will be more robust and agile than any other build. If we want to make smaller raceways with smaller bodies of water, we can just disconnect two sets of panels opposite each other in the raceway and reconnect the others. If we want to make larger raceways with larger bodies of water, we can just connect additional two sets of panels opposite each other in the raceway and bolt everything together. If we want to move the raceway altogether to a different location for any reason (rented facility no longer accessible, moving the farm, etc), just disconnect everything and move it easily in those straight panels, one by one! Note that the HDPE liner we use is tough enough for us to adjust but easily and cheaply replaceable many years down the road.

In addition, the heating and plumbing system will be upgraded. Instead of using hydronic heating system or heating through the air, neither as efficient as heating the water directly, a Hayward 50K BTU heat pump will be used to heat (and chill, which is an added option in the summer months!) the water directly. The water will be pumped from the pond on one end with a 1HP Hayward pump into the heat pump and then sent back into the pond through the other end through a number of nozzles, effectively creating a continuous raceway in one direction to prevent dead zones.

The above raceway design will function as our “treatment” to see if we can answer the two questions we are trying to solve: if there is a more efficient, durable, and cost-effective fish/shrimp production design for indoor aquaculture and if there is a more efficient and simple way to heat the water specifically in the Midwest, where there are winter seasons to deal with.

For the “control” group, we will use (2) 14’ FT circular swimming pools normally used at OceanArc facilities to compare the performance of how the saltwater shrimp grow compared to how they grow in the “treatment” design.

1. Evaluate how well the metal frame raceway design with HDPE liner holds up through several grow out cycles of saltwater shrimp compared to the typical swimming pools used.
2. Compare harvest weight and survival rates between shrimp raised in the raceway design and shrimp raised in the swimming pool design.
3. Measure temperature daily (preferably continuously if possible) for both raceway and swimming pool designs to test temperature uniformity through the grow cycle.
4. Compare energy usage between the raceway design that heats water directly and the swimming pool that heats water through hydronic heat.
5. Share findings to fellow farmers and potential farmers through presentation at the Ohio Aquaculture Association Annual Conference.