Effects of environmental stress on the development of the immune system, growth and survival in the early life stages of wild salmon

Project summary Recent studies demonstrate disturbed immunological responses in fishes exposed to environmental stressors, including solar ultraviolet B (UVB) radiation. Taken together, these findings strongly suggest that the immune system, growth and survival of fishes is significantly impacted by exposure to such stressors. At the population level, such a reduction in immune response might be manifested as lowered resistance to pathogens (including parasites) and in increased susceptibility to diseases. The ability of the fish immune system to accommodate increased exposures to environmental stressors is unknown. We propose to evaluate (for the freshwater-resident early life stages of salmon) the effects of long-term, sub-lethal exposure to an environmental stressor ( UVB radiation) on (1) the development of the immune system; (2) individual and population-level growth rates; and (3) survival. We also propose to establish whether there is an interaction between the organism's nutritional status, the development of its immune system, and its ability to deal with pathogenic challenges. This research will contribute to our general understanding of the effects of environmental stressors on commercially important fish populations.