Although from viewing our photos you’d think we live under the sea, the Expedition Akumal volunteers occasionally work above water! We have a group of our volunteers that recently celebrated the completion of a sustainable aquaponics system right outside our office here in Bungalow 207 at the Hotel Akumal Caribe. Over the past few months we have watched it go from bare concrete to a bubbling fish tank and flourishing green plant beds, so we thought it was about time we turned the topic from our underwater coral garden to our above water fish and vegetable garden.
Aquaponics is a soil free food-production method that has two main sections: a large tank full of fish, and several low, long plant tanks. The fish tank can hold approximately 30 kgs (70 lbs) of fish, and was started two months ago with 500 young tilapia. The vegetable gardens have floating Styrofoam beds where plants grow in little pots filled with 50/50 coconut fibre and vermiculite, with only their roots touching the water. The water constantly flows from the fish tank to the troughs and back again, and an aerator adds oxygen into the mix. Within the system, the fish provide the plants with all the nutrients they need to grow, and the plants clean the water for the fish.
“It’s a perfect relationship,” says Lorrie Fossheim, who spearheaded the creation of the system with her husband Jim, and support from Laura and the staff at Hotel Akumal Caribe, “there is no need to water or weed. We just feed the fish, and top up the water if too much evaporates in the dry season.”
Thanks to some big storms while the system was being set-up, the primary water supply so far has been fresh rain water. The tank is kept as close to Ph. neutral as possible, and is filled with healthy bacteria which convert the fish waste into nitrates. This ‘enriched’ water circulates into the plant troughs, where the free hanging roots of the plants take up the nitrates as food. Using vermiculite and coconut fibre in place of soil helps keep unwanted bacteria out of the cycle, and maintains the delicate balance of the system.
Insert image from Thomas of graphic on fish tank
After only a few weeks, the garden is close to yielding its first crop of romaine lettuce, and the team also has cauliflower, broccoli, string beans, cabbage, cantaloupe, basil, cilantro, spinach, celery, and chard seedlings out-planted and growing fast. Tomatoes, watermelon, honeydew melons and gem squash will be included in the next planting. A shade canopy has been built over the beds to protect the plants (and the volunteers) from direct sunlight.
Insert attached photo of garden: Expedition Akumal Volunteers check on the progress of the plants
The tilapia feed voraciously, jumping at the pellets volunteers scatter on the surface of their tanks, and they are also visibly growing larger. The water quality is monitored through weekly tests to check on the Ph. balance. Too many large fish would produce too much waste, and upset the delicate balance of the eco-system. To prevent this, when the tilapia reach between 0.5 and 1 kg in weight (1-2 lbs) they will be removed. Being a sustainably raised food source they will probably find their way onto a dinner plate, maybe along with a fresh green salad from the garden!
The eventual plan, pending permissions, is to serve fresh, organically and sustainably grown vegetables and fish in the restaurant. But for now, the aquaponics system is still in the trial stages.
“We are going to be on a learning curve for a while,” says Lorrie, who would love to see strawberries and stevia added to the garden. “It would be so awesome if (stevia) would grow, we could use it to sweeten the Jamaica drinks at the restaurant.”
Whether strawberries or stevia can be grown or not remains to be seen, but there is no question that the first group of plants in the floating pots are doing well. If you are in Akumal and would like to see them, stop by the Expedition Akumal office at Hotel Akumal Caribe Bungalow 207 anytime. A beautiful graphic on the side of the fish tank shows the flow of the system, and you can sit at our planting table and learn more details from the laminated booklet that is kept there.
Insert image from Thomas: Wideshot of system showing seating area
Stay involved with all the Expedition Akumal projects by coming to LolHa for our weekly talk on Fridays at 4:30pm, or drop us an email to arrange a visit and feed the fish!