Growing Mealworms as a Fish Feed for Sustainable Aquaponics

Problem

One of the greatest challenges to growers in the North Central Region is how to maximize returns by extending the growing season to supply the continuing demand for fresh, local produce year-round.

Extreme weather events such as droughts, flooding and excessive temperature fluctuations have placed a greater emphasis on developing controlled-environment facilities including greenhouses, high tunnels and warehouses with supplemental lighting to grow harvestable crops.

Many small farmers are utilizing high tunnels to extend the growing season and increase productivity by using bio- intensive methods and are searching for high value crops to generate needed farm income.

Developing growing practices that efficiently use water and energy are critical for creating economically sustainable farms in our climate region.

In just the past few years, there has been considerable interest in aquaponics as a means of addressing this challenge. Consumer demand for fish is increasing, while wild fish harvests continue to dwindle; creating a market demand for locally raised fish.

The high cost of commercial fish feed presents a challenge to growing fish in an economically sustainable manner. According to the President of the Ohio Aquaculture Association, “Rising feed costs may be the most important bottleneck aquaculture and aquaponics face.”

The lack of certified organic feed sources for fish production also is a challenge for those desiring certification of organically grown fish.

Key challenges to be investigated by this research project:

• Can we grow sufficient quantities of mealworms using organic certified grains or grain waste products in a high tunnel environment for use as a fish feed integrated with an aquaponics cropping system?

• Can this be done in a cost effective manner that will provide much needed income for a small farmer operation and provide fresh fish and produce to meet with the increasing demand for locally grown food?

Solution

Aquaponics offers a potential new revenue stream for farmers to utilize limited space or non-agriculturally suitable land to increase profitability, while having the environmental benefits of improved water and nutrient use efficiency for growing consumable plants.

This project will help determine whether mealworms can be grown in a cost effective manner that either reduces the expense for fish feed by replacing or supplementing commercial feeds and/or increases the yields of fish or produce harvested for sale.

One of the challenges will be maximizing mealworm production in a passive solar high tunnel with fluctuating daily and annual temperatures.

This research proposes to:

1. Evaluate availability of local organic grain or grain waste byproducts for use as a mealworm growing substrate.

2. Evaluate locally available plastic food bins, discarded by local restaurants, for optimum container depth. 1 1⁄2 inch deep and 5 inch deep containers with lids are available to be modified with screening in the lids to serve as bins for growing mealworms.

3. Design a modified, shaded and insulated growing area within the passive solar high tunnel to minimize temperature fluctuations. Temperature data loggers will be used to develop these enclosures and document temperatures.

4. After determining optimal substrates, growing bins and modified growing enclosure, sufficient amounts of mealworms will be grown to determine costs of production, feed conversion rates and nutrient content.

5. Based on the nutrient content, fish feed will be formulated to meet with nutritional requirements of hybrid bluegills being grown in a large 1,500 gallon aquaponic tank.

6. A commercial fish feed will be compared in a separate, adjacent same sized aquaponic tank.

7. Measurements will be made for fish and plant yields in these two systems. Water quality and tissue analysis will be done to determine any differences between the treatments.