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Bioeconomic Model for the Evaluation of Backyard Aquaculture Systems for Tilapia

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By Milthon Lujan

Backyard systems are considered agroecosystems in which families produce various species of animals and plants for their consumption and savings. Savings in labor and land costs are key elements for the economic viability of these systems.

The profitability of backyard aquaculture under different scenarios has not yet been determined. Bioeconomic tools allow for profit projections of any production system.

In this regard, researchers Juan Carlos Dorante and Alfonso Maeda from the Nayarit Unit of the Center for Biological Research of the Northwest propose a bioeconomic model, composed of biological, production, and economic submodels, to evaluate the low-cost backyard aquaculture system (BAS), suitable for rural communities in Mexico.

Backyard Aquaculture System (BAS)

The researchers designed a closed-loop system that was easy to operate, consisting of a 2,800-liter plastic tank, equipped with a submerged 0.046 hp Venturi pump for water recirculation.

The tank was stocked at a density of 60 individuals/m3, and the cultivation period lasted 25 weeks. Tilapia fingerlings were fed daily at a rate of 5 to 1% of their body biomass in daily rations from 10 to 4.

After stocking, daily activities included checking the temperature, determining ammonia concentration, and chlorine levels.

Bioeconomic Model

The bioeconomic model consisted of three submodels: biological, production, and economic. Each of these models worked independently from the others.

  • The biological submodel comprises dependent and independent variables that influence growth, such as biomass, oxygen requirements, temperature, and expected mortality.
  • The production submodel includes variables such as tank volume, stocking density, initial and final weights of the fish, aeration system capacity, harvested biomass, and feed conversion ratio.
  • The economic submodel includes data on expenses and revenues, as well as output data such as profits and profitability indicators.
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Main Results

The researchers projected a final weight of 614 g in a 25-week cycle, with a feed conversion ratio of 1:1.2, and estimated a harvest of 186 kg/year of fresh tilapia.

“Considering the final weight of the fish, the amount of feed required, and the number of pumps, the investment required to build and operate a backyard aquaculture system for one year will be $1200, including $775 of investment and $425 of production costs,” they report.

Furthermore, they describe that with a total cost of $425.26 for a production of 186 kg/year, the cost per kilogram of fish is $2.29.

Self-Consumption Evaluation

The researchers evaluated three levels of self-consumption: 0%, 10%, and 25%. Based on these considerations, the 0% self-consumption level has a cost-benefit indicator of 1.12 and an internal rate of return of 21.7%.

According to the study results, at a 10% self-consumption level, a five-member family can consume 3.8 kg of fish per year, a value that exceeds the average per capita apparent consumption of tilapia in Mexico (3.08 kg/individual) and worldwide (0.9 kg/individual).

Conclusion

“The evaluated backyard aquaculture system proved to be a viable and self-sustainable alternative for tilapia production on a small scale in rural areas of Mexico and other Latin American countries,” the researchers conclude.

Finally, they describe that the BAS system can contribute to reducing the deficit in tilapia consumption in rural families in Mexico if adopted on a large scale.

The study was funded by the National Council of Science and Technology and the Graduate Program and Human Resources Training of the Center for Biological Research of the Northwest.

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Reference (open access)
Dorantes-De-La-O, Juan Carlos R., & Maeda-Martínez, Alfonso N.. (2023). Bioeconomic model for the evaluation of a backyard aquaculture system for tilapia (Oreochromis niloticus). Latin american journal of aquatic research, 51(2), 282-294. https://dx.doi.org/10.3856/vol51-issue2-fulltext-2999

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