Risk Factors Associated With Tenacibaculosis-Related Mortality in Farmed Salmon in Chile From 2018 to 2021

Area of Science:

• Aquaculture
• Fish Pathology
• Marine Biology

Background:

• Tenacibaculosis, caused by Tenacibaculum bacteria, is a significant emerging disease in Chilean marine salmon farming.
• It is a leading cause of mortality, impacting Atlantic salmon, Coho salmon, and rainbow trout across major farming regions.

Purpose of the Study:

• To conduct epidemiological analyses of tenacibaculosis in Chilean salmon farming.
• To identify key risk factors and seasonal patterns associated with the disease.

Main Methods:

• Descriptive epidemiological analyses, time-series decomposition, and survival analysis were performed.
• A case-control study utilized official surveillance data from 1192 production cycles (2018-2021).
• Logistic regression models assessed risk factors for tenacibaculosis reporting.

Main Results:

• Tenacibaculosis affected 65.2% of studied production cycles, showing a distinct seasonal pattern with higher mortality during low water temperatures (6°C-12.7°C).
• Significant risk factors included infestation with Caligus rogercresseyi (OR=3.23) and Atlantic salmon farming in Aysén (OR=5.41).
• Disease onset varied by region and species, with earlier onset in Atlantic salmon and rainbow trout compared to Coho salmon.

Conclusions:

• Tenacibaculosis presents significant epidemiological challenges in Chilean salmon farming, strongly influenced by water temperature.
• Caligus rogercresseyi infestation and specific regional farming conditions are critical risk factors.
• Findings inform disease prevention and management strategies for the aquaculture industry.