Expert-Based Prioritization of Control Measures for Salmonid Rickettsial Septicemia in Chilean Salmon Aquaculture

Piscirickettsiosis (SRS) remains the main infectious disease affecting salmon aquaculture in Chile. This study evaluated expert perceptions of the effectiveness of SRS control measures and the level of agreement among industry professionals. A structured cross-sectional expert-elicitation survey was conducted with nine head fish health managers representing more than half of the Chilean Atlantic salmon and rainbow trout production. Experts scored 67 control measures using a 5-point Likert scale, and effectiveness and consensus were assessed using descriptive and variability metrics. Measures related to biosecurity, mortality management, and production practices ranked highest and showed strong agreement. Therapeutic and vaccination-related measures showed heterogeneous levels of agreement: several specific antimicrobial protocols (oral florfenicol, injectable oxytetracycline monotherapy, and combination florfenicol + oxytetracycline therapy) reached high consensus, while other therapeutic measures and most vaccination strategies exhibited substantially greater variability. The integration of effectiveness and consensus enabled classification of measures into priority tiers, consistently highlighting preventive strategies as high priority. These findings provide a structured, practice-oriented framework to support decision-making and reinforce the importance of management-based approaches for SRS control under field conditions.