Stakeholder Knowledge and Parasitological Evidence: A Mixed-Methods Approach to Tilapia Health in Kenya

Abstract

Nile tilapia (Oreochromis niloticus), a key farmed fish globally, faces under-reported parasitological challenges. In Kenya's Upper Tana River region, we conducted a mixed-methods study combining biological health assessments with a qualitative survey on fish health management. From mid-January to mid-February 2024, we examined 157 Nile tilapia for parasite diversity and tissue-level impacts. Parasites from external and internal organs were identified using light microscopy, molecular barcoding, and scanning electron microscopy. We documented a diverse parasite assemblage, including members of Clinostomum, Euclinostomum, Cichlidogyrus, Scutogyrus, and Acanthogyrus, with variable prevalence and intensity among hosts. Histopathological examination of gill, intestine and liver tissues was performed and the gill tissues revealed notable changes typical of infections including epithelial hypertrophy and hyperplasia, lamellar fusion, vascular congestion of secondary lamellae, and associated inflammation. In parallel, we engaged 48 stakeholders (36 fish farmers, 11 fisheries and extension officers, and one veterinarian) to understand local knowledge and practices. Findings showed persistent neglect of parasites in farm decision-making a “don’t know, don’t care” dynamic. This is driven by low awareness, weak diagnostic capacity, and limited institutional feedback. Farmers rarely linked disease signs to parasitism, and training gaps among extension officers eroded trust, encouraging improvised treatments. Framed as “undone science”, this local neglect is structural rather than individual. We propose a Challenge and Reconstruct Learning (ChaRL) approach. This method uses parasitological evidence to prompt collective reflection and coordinated action. By making biologically confirmed infections visible, this study bridges pathology and practice, offering a practical way to improve tilapia health management in the region.