DOI: 10.1079/cabionehealth.2026.0024 ISSN: 2791-223X
A systems approach to freshwater fish farming in Tunisian reservoirs: Analysing zoo‑sanitary registration and its implications for One Health
Sami Mili, Rym Ennouri, Siwar Agrebi, Naoufel Romdhane, Houcine Laouar Abstract
Background
: The One Health approach recognises the inextricable links between human, animal and environmental health. Zoo-sanitary registration of fish farms is a key regulatory tool designed to ensure animal health and food safety. However, its implementation often encounters unforeseen barriers.
Methods
: This study uses systems thinking to compare three governance models (private promoters, fishery development groups and independent fishermen) across three Tunisian reservoirs (Lahjar, Kasseb, and Siliana), assessing their compliance with the zoo-sanitary registration procedure. Data were gathered through field surveys, semi-structured interviews, institutional archives, the official regulatory guide and two standardised ecological assessments. SWOT analysis and stakeholder interviews informed the construction of a causal loop diagram (CLD) to visualise systemic interactions.
Results
: The results reveal stark disparities: only the private promoter at Lahjar has a complete registration file. The CLD shows that the current system creates implicit barriers, trapping small-scale operators, independent fishermen and an inactive development group in a negative feedback loop that perpetuates non-compliance, limits market access and hinders investment in sanitary equipment. Ecological data confirm this dynamic: at Kasseb, which has the weakest governance, catch per unit effort decreased by 89% between 2015–2016 and 2020–2021, reaching critically low levels of four fish per 1000 m
2
of nets. At Siliana, catches fell by 65% despite the existence of a formal group structure. Even in Lahjar, where compliance is observed, the fish community is imbalanced, partly due to intensive cage culture.
Conclusions
: Effective and equitable One Health policies must go beyond administrative requirements, address the underlying causes of non-compliance and explicitly incorporate environmental health indicators. This study demonstrates the value of systems thinking in identifying implementation failures and proposing ways to achieve sustainable governance of freshwater aquaculture.
One Health impact statement
This study uses a systems-thinking approach to reveal how Tunisia’s well-intentioned zoo-sanitary registration policy inadvertently excludes small-scale fishers and fails to protect ecosystem health. By combining governance analysis with ecological time series, we demonstrate that administrative compliance alone does not ensure sustainability.
Our transdisciplinary approach, which brought together fisheries scientists, veterinarians, social scientists and local operators, uncovered feedback loops that perpetuate inequality and environmental degradation. Overcoming these barriers requires the strengthening of collective governance arrangements that enable local actors to jointly manage resources, align incentives and foster trust among stakeholders (Ostrom,
1990