Prawns + Aquaponics = Three Course Meal!

The aquaponics system at CEI produces enough lettuce to feed our community twice a day, seven days a week.  The fish production is increasing in the next year, and provides one meal a week of fresh tilapia.  Right now the system is good, but does have a few minor opportunities for improvement.  One issue we are facing is an over-abundance of solid waste settling out at the bottom of our deep water hydroponic beds. One way to solve this “problem” is to install additional filters which would have to be purchased, shipped, installed, and run on electricity. The filters would use more fresh water to clean, and require more time and maintenance.  This isn’t the ideal solution when we are trying to reduce imports, simplify operations, maintain affordability, and conserve water.  Cape Eleuthera Insistitute, prawns for aquaponics

We instead looked for a permaculture way of solving the solid waste issue, and found one!Last Friday a shipment arrived at Governors Harbor Airport of three small boxes from a company in Florida called Miami-Aquaculture Inc.  Inside the three boxes were approximately 2,000 post-larval giant freshwater prawns (Macrobrachium rosenbergii) which can grow to twelve inches in length in just one year.  Conveniently, these prawns are detritivores and occupy the exact niche we are lacking in our aquaponics system.  Once they grow large enough to be stocked out into the grow beds they will convert any organic material that precipitates out into animal matter, meaning shrimp dinners in the future!

This is one example of how permaculture can take a problem and turn it into the solution.  Instead of a waste problem we had a prawn deficiency!  Now we will be able to harvest the appetizer, the fish, the herbs to season the fish, and the salad, all from one system without adding any more feed, water, or electrical use. We will also maintain the simplicity and affordability of setting up an aquaponic system.  A win win for all!

Joshua Shultz

Permaculture Manager

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