Technical efficiency analysis of marine shrimp farming (Litopenaeus vannamei) in biofloc and conventional systems: A case study in northeastern Brazil

Abstract Shrimp farming has a great ecological, economic, and social importance in northeastern Brazil. Although the conventional farming system is widely used, biofloc technology (BFT) system has been developed to reduce environmental impacts and optimizing the production. Thus,the present study evaluated the technical efficiency of production cycles of Litopenaeus vannamei in conventional and BFT systems.We analyzed 48 production cycles in the conventional system in 2013 and 2014 and 9 cycles in the BFT system in 2014 through data envelopment analysis (DEA). The inputs corresponded to the population density (post-larvae m-2), amount of feed (kg ha-1 cycle-1), labor (man ha-1) and power supply (HP ha-1), whereas the yield (kg ha-1 cycle-1) was considered the output. The results indicated four production cycles (7.0%) technically efficient, three in the conventional system and one in the BFT. By comparing the productive systems, there was significant difference in their mean scores of technical efficiency. There was a greater influence of the management inefficiency on the conventional system, while the production scale reduced the average scores of technical efficiency in the BFT system. These results may help to improve the development of sustainable L. vannamei farming in both systems by reducing waste and increasing profits.

摘要：巴西东北部的虾类养殖具备显著的生态、经济与社会价值。尽管传统养殖系统应用广泛，但生物絮团技术（biofloc technology, BFT）体系已被研发用于降低环境影响并优化生产效能。为此，本研究针对凡纳滨对虾（Litopenaeus vannamei）在传统养殖与BFT体系中的生产周期技术效率展开评估。
本研究通过数据包络分析（data envelopment analysis, DEA），分析了2013至2014年间传统养殖体系下的48个生产周期，以及2014年BFT体系下的9个生产周期。研究选取的投入指标包括养殖密度（仔虾数·m⁻²）、饲料投喂量（kg·ha⁻¹·周期⁻¹）、人力投入（人·ha⁻¹）与电力供应（马力·ha⁻¹），产出指标为单位养殖产量（kg·ha⁻¹·周期⁻¹）。
研究结果显示，共有4个生产周期（占比7.0%）达到技术效率标准，其中传统体系3个，BFT体系1个。对比两种养殖模式可见，二者的技术效率平均得分存在显著差异。传统体系的技术无效率受管理因素影响更为突出，而BFT体系则因生产规模拉低了其技术效率平均得分。上述研究结果可为两种模式下凡纳滨对虾的可持续养殖发展提供参考，助力减少资源浪费、提升养殖收益。