Bioeconomic analysis of deterministic and stochastic partial harvesting in the production of spring genetics tilapia variety restricted to minimum market sizes

Abstract

A bioeconomic model was used for commercial tilapia culture to evaluate different partial harvest strategies. This study considered homogeneous and heterogeneous seeding sizes. The impact of one and two partial harvests was evaluated. In the first case 25% of the population was harvested (I), in the second 50% (II), in the third 25% and 25% (III), and in the fourth 50% and 25% (IV). Four minimum market sizes were considered: 350, 400, 450, and 500 g. The results indicated that a first partial harvest of 25% or 50% of the population as well as two partial harvests with a homogeneous seeding sizes generated the highest net benefits, with US$3954.32 and US$4303.52 at a minimum market sizes of 500 g. Mortality rate, mean water temperature, feed cost and product price were considered as sources of uncertainty and were simultaneously analyzed in the bioeconomic model using Monte Carlo analysis. An initial partial harvest of 25% of the population followed by two partial harvests with a homogeneous seeding sizes and a minimum market sizes of 500 g presented the lowest uncertainty and an expected loss of 32.84% and US$0.00, respectively. An initial partial harvest of 50% of the population as well as a partial harvest with a heterogeneous seeding sizes presented the lowest uncertainty (31.97%), while two partial harvests with a homogeneous seeding sizes presented the lowest expected loss of US$-2.09, in both cases with a minimum market sizes of 500 g. It provides relevant information to the producer for decision-making in the management of seeding and harvesting, to improve their economic, considering minimun market sizes.