Sustainable Tilapia Aquaculture Production Demonstration Facility

ABSTRACT

We designed and built a fully functioning aquaponics system on our farm in American Samoa, and we stocked the system with six successful spawn. We eventually increased the stocking in preparation for culturing vegetables.

OBJECTIVES

1. Develop a model facility incorporating several sustainable forms of freshwater aquaculture.
2. Transfer technology to implement sustainable aquaculture practices for the culture of tilapia species in American Samoa.
3. Aid in the advancement of alternative agriculture systems for subsistence and commercial aquaculture-agriculture production.

RESULTS

We purchased building supplies, water pumps, an air pump, plumbing and tarps; we hired two laborers and with their help, improved the existing tanks by adding another foot of height and sealing the inner surfaces. We constructed a separate tank to act as a solids settling tank, with dimensions of 4x3x4ft and it was plumbed to an overflow pipe from the settling tank.

We purchased cement boards to construct 10x2.5x1 ft boxes for growing vegetables, which have been plumbed to the overflow pipe from the settling tank. These vegetable boxes also overflow to a sump tank. A water pump was purchased to return water from the sump tank to the fish tank.

We acquired fish broodstock from a local farm and one spawn has been successfully induced. We acquired hapa nets from Sea Grant to separate adult fish, induce spawning, and separate juveniles from adults. We purchased fishmeal from one of the local tuna canneries, which we delivered to the fish twice a day along with breadfruit and coconut. This has been supplemented with a manufactured feed sold commercially. We maintained a record of feed weight per day to monitor feeding activity and to enable calculation of feed conversion ratios.

We conducted one workshop to demonstrate tilapia aquaculture. We held a second workshop after plants were growing well and demonstrated aquaponics technology and distributed samples of watercress.

It took several trials to find a good vegetable for aquaponics. We started with tomatoes and eggplant, both of which did not do well. We floated plants on the surface of the water using Styrofoam sheets with holes cut to insert plants. We tried Chinese water spinach, which grew very well, but didn’t sell. We then switched to watercress, which grew well and was easier to market.

BENEFITS OR IMPACTS ON AGRICULTURE

Implementing a recirculating aquaculture/aquaponics system resulted in two different organisms being cultured, tilapia species and watercress vegetables. The recirculating system conserved water by reusing the same water over and over. This is accomplished by filtering the fish tank water through the roots of the watercress plants which remove nutrients in the water harmful to the fish, making the water safe for the fish. Less land is needed to grow the watercress plant as they were grown in old freezer boxes placed next to the fish enclosures.

OUTREACH

Community awareness to sustainable forms of freshwater aquaculture was accomplished through two workshops and participation in the American Samoa Youth Summit by presenting on freshwater aquaculture, using the project facility as a model.

I was invited by the local Department for Women and Youth Affairs to present information on tilapia aquaponics. Additionally, 130 high school students spent 15 minutes each at my booth where I taught them about aquaponics.

RECOMMENDATIONS AND NEW HYPOTHESIS

With successful spawning, which increased stocking densities and a demand for the watercress, expansion of the current aquaculture/aquaponics facility is recommended.