Temperature affects settlement success of ectoparasitic salmon lice (Lepeophtheirus salmonis) and impacts the immune and stress response of Atlantic salmon (Salmo salar)

In this study, the effect of temperature on Atlantic salmon (Salmo salar) stress and immune response to the ectoparasitic salmon lice (Lepeophtheirus salmonis) was investigated. We found that infestation affected the expression of several immune and wound healing transcripts in the skin especially at the site of lice attachment compared to un-infested control fish. Moreover, expression patterns in the skin of infested fish suggest that host immune responses towards salmon lice are impaired at low temperatures. However, reduced lice infestation success and survival at the lowest investigated temperatures suggest that cold water temperatures are more detrimental to the lice than their fish hosts. Finally, temperature affected the stress response of the fish and infected fish had a higher increase in cortisol levels in response to handling (a stressor) than un-infested controls.

Automated summary

In this study, the researchers investigated the impact of temperature on stress and immune response of Atlantic salmon to salmon lice infestation. The results showed that lice infestation affected the expression of immune and wound healing genes in the skin, especially at the attachment site. The study also found that low temperatures impaired the host immune responses toward salmon lice, but had a more detrimental effect on the lice themselves. Additionally, the fish infected with lice had a higher increase in cortisol levels, indicating a higher stress response compared to un-infested fish.