Strategies for feeding tilapia in smallholder aquaculture systems: a study of aquaculture feed access and availability in two districts of Northern Province, Zambia

Aquaculture contributes to agricultural development, economic growth, and poverty reduction initiatives in Zambia. In northern and rural regions of the country, development requires improvements to the management of local and farm-generated inputs. Fish farmers have limited market access and purchasing power, which restricts access to commercial inputs, such as formulated feeds and chemical fertilizers. Instead, farmers adopt integrated-agriculture-aquaculture (IAA) practices, whereby on-farm resources supply essential inputs. Research is limited regarding local systems of resource management, and this hinders development of innovations for improving efficiency. This mixed-methods study explored local patterns of resource utilization. Smallholders (n = 63) participated in surveys and interviews regarding resource management. A series of quantitative analyses, including descriptive statistics, principal component analyses (PCA), and multinomial logistic regression (logit) models, identified relationships between these resources, household livelihood, and system productivity. Qualitative analyses explored farmer perceptions regarding seasonal resource availability. Results suggested that livestock manure, homemade feeds comprising maize and soybean, garden residues, and kitchen wastes were the most frequently selected inputs. Logit models of feeding intensity found that income, proximity to Luwingu Town, experience in aquaculture, and access to extension services were key household resources. High-intensity feeding strategies incorporated commercial feeds, chemical fertilizers, as well as home-made feeds containing a wide diversity of both high- and low-quality ingredients. Low-intensity feeding strategies incorporated only farm waste and termites. Potential innovations that may improve system performance in resource poor contexts are considered and recommendations for additional research are offered.

水产养殖业对赞比亚的农业发展、经济增长及减贫事业均具有重要支撑作用。在该国北部与农村地区，产业发展亟需优化本地及农场自产生产投入品的管理模式。当地养鱼户的市场准入渠道与购买力均较为有限，这制约了其获取配合饲料、化肥等商业化生产投入品的能力。为此，养殖户转而采用农渔综合种养（integrated-agriculture-aquaculture, IAA）模式，依托农场自产资源作为核心生产投入品。当前针对本地资源管理体系的研究较为匮乏，这阻碍了高效提升生产效率的创新方案研发。本项混合方法研究旨在探究当地的资源利用模式：共有63户小农参与了有关资源管理的问卷调查与访谈。研究通过一系列定量分析方法——包括描述性统计（descriptive statistics）、主成分分析（principal component analyses, PCA）以及多项逻辑回归（multinomial logistic regression, logit）模型——揭示了各类资源、农户生计与系统生产效率之间的关联；定性分析则探究了养殖户对季节性资源供给状况的认知。研究结果显示，畜禽粪便、以玉米与大豆为原料的自制饲料、菜园废弃物以及厨余垃圾是养殖户最常选用的生产投入品。投喂强度的多项逻辑回归模型结果表明，家庭收入、距卢温古镇（Luwingu Town）的距离、水产养殖从业经验以及技术推广服务可及性是影响农户资源配置的核心因素。其中，高强度投喂策略会同时使用商业化饲料、化肥以及成分多样、品质参差不齐的自制饲料；而低强度投喂策略则仅使用农场废弃物与白蚁。本研究还探讨了在资源匮乏情境下可提升系统生产效能的潜在创新方案，并为后续研究提出了相关建议。