Abstract Elevated salmon louse infection pressure generated by farming represents a major threat for wild Atlantic (Salmo salar). This study explored the effect of lice on mortality, and body gonad growth in F1 salmon. Mature males (jacks) immature fish were either infected with two different intensities (LIIs, 0.08 or 0.35 g−1) kept as uninfected controls. Fish maturation was thereafter enviro...

Pathogens are increasingly emerging in human-altered environments as a serious threat to biodiversity. In this context of rapid environmental changes, improving our knowledge on the interaction between ecology and evolution is critical. The objective of this study was to evaluate the influence of an immunocompetence gene, the major histocompatibility complex (MHC) class IIbeta, on the pathogen ...

Major histocompatibility complex (MHC)-dependent mating preferences have been observed across vertebrate taxa and these preferences are expected to promote offspring disease resistance and ultimately, viability. However, little empirical evidence linking MHC-dependent mate choice and fitness is available, particularly in wild populations. Here, we explore the adaptive potential of previously ob...

In vertebrates, variability at genes of the Major Histocompatibility Complex (MHC) represents an important adaptation for pathogen resistance, whereby high allelic diversity confers resistance to a greater number of pathogens. Pathogens can maintain diversifying selection pressure on their host's immune system that can vary in intensity based on pathogen richness, pathogen virulence, and length...

The teleost gill forms an extensive, semipermeable barrier that must tolerate intimate contact with the surrounding environment and be able to protect the body from external pathogens. The recent discovery of the interbranchial lymphoid tissue (ILT) has initiated an anatomical and functional investigation of the lymphoid tissue of the salmonid gill. In this article, sectioning of gill arches in...

We have tested the importance of genetic variation in the major histocompatibility complex (MHC) class IIB in Atlantic salmon (Salmo salar) for survival after challenge with a highly virulent bacterial pathogen. Forty juvenile full siblings from each of 120 families were infected with the bacterium Aeromonas salmonicida, which causes high mortality in salmon due to furunculosis. Fishes from hig...

Fish gills are delicate structures, which vulnerable to damage from pathological as well non-pathological aetiologies. They frequently sampled for histology they involved in many recognised disease processes. Artefacts, arising sampling techniques, can potentially interfere with interpretation of gill histology. A range possible processes that result artefact were assessed a group freshwater At...