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Research Project: Genetic Improvement of North American Atlantic Salmon and the Eastern Oyster for Aquaculture Production

Location: National Cold Water Marine Aquaculture Center

Title: Sea lice Lepeophtheirus salmonis resistance in three strains of Atlantic salmon salmo salar

Author
item Pietrak, Michael
item Lifgren, Demitri
item Delomas, Thomas
item Polinski, Mark

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2025
Publication Date: 3/6/2025
Citation: Pietrak, M.R., Lifgren, D.L., Delomas, T.A., Polinski, M.P. 2025. Sea lice Lepeophtheirus salmonis resistance in three strains of Atlantic salmon salmo salar (abstract). Aquaculture America Conference. 03062025.

Interpretive Summary: A study was conducted to determine if different strains of Atlantic salmon with different long-term histories of exposure to sea lice in the wild would have different levels of resistance. Three strains, one that is sea run salmon and has always been exposed to sea lice, one that is a land locked strain with no history of exposure to lice, and third strain that is typically land locked but does have access to the ocean to be exposed to sea lice were used. The challenge showed that the land locked strain with no previous exposure to sea lice was less resistant to sea lice than the other two strains. In all three strains the immune response at sites with attached sea lice was similarly to sites without sea lice. These results suggest that sea lice resistance can be selected for in Atlantic salmon, but that an immune response may not be the primary means for the observed variations in response.

Technical Abstract: The USDA National Cold Water Marine Aquaculture Center (NCWMAC) has been evaluating families of North American Atlantic salmon (Salmo salar) for resistance to sea lice (Lepeophtheirus salmonis) since 2015 and are currently evaluating the second generation of families selected for sea lice resistance. With the spawning of the second generation in 2021, the USDA began several different efforts to evaluate the success of the selection program. One of the efforts was to identify if different strains of Atlantic salmon with discrete long-term exposure histories to sea lice had different levels of resistance. This effort was supplemented with fin and skin transcriptomic profiling of each strain at sites of infection and at parasite free locations to investigate what factors might explain phenotypic differences between the strains.