Vaccination against francisellosis in farmed cod in light of the changing climate

The VaxiCod project will bolster the cod renaissance by optimizing vaccination strategies against Francisella noatunensis.

In addition to disease, cod farming must also address the emerging threats posed by climate change. This project will specifically explore how climate change-related stressors impact the efficacy of the developed vaccine candidates.

Background

In Norway, Atlantic cod aquaculture is a fledgling industry compared to Atlantic salmon. However, the recent resurgence of interest, following several years of setbacks, has highlighted the immense potential of the industry, especially in Northern Norway. This renewed interest aligns with current discussions on species diversification as a means of adapting to the changing climate.

To achieve these goals, improving disease resistance is crucial. Currently, vaccination remains the most effective method for preventing diseases.

In VaxiCod, we will explore the interaction between vaccination and climate change-related stress in Atlantic cod. This project will address one of the most challenging diseases in cod: francisellosis, caused by Francisella noatunensis.

We have preliminary evidence that the development of the disease in cod is highly affected by climate change-related stress such as temperature, and that candidate vaccines against the pathogen show potential in reducing the severity of disease-related pathologies. This evidence forms the foundation for exploring the interplay between vaccine efficacy and stress related to a changing climate.

In this project, we will vaccinate the fish and expose them to the pathogen under conditions simulating climate change related stress; progressively increasing temperature and reduced dissolved oxygen levels.

VaxiCod is expected to contribute to improving the health of farmed cod through optimized vaccination strategies under the threats posed by climate change. This project will be pivotal in further developing the cod farming industry in Norway.

Goal

The main overarching aim of VaxiCod is to improve disease resistance of Atlantic cod against Francisella noatunensis through a vaccination protocol that takes into consideration the potential influence of climate related stressors on the efficacy of candidate vaccines.

Specifically:

• Evaluate the effects of elevated temperature and lower oxygen on the physiology of vaccinated and unvaccinated cod
• Determine the efficacy of vaccination under challenging conditions, i.e., elevated temperature and lower oxygen