Infestation susceptibility and anti-parasite behaviours among salmonids
Epidemics of salmon lice drive the need for better understanding of the host susceptibility, and differences among salmonid species, to forecast potential impacts on salmonid populations or determine the factors of susceptibility. The aim of this experiment is to test the difference in susceptibility to salmon lice among various types of salmonids. We will use 7 groups of salmonids: naive wild sea trout, previously infested wild sea trout, domestic Atlantic salmon, hatchery Chinook salmon, clonal line Atlantic salmon, diploid clonal salmon (3 clonal female origin, 1 male) and triploid clonal salmon (3 clonal female origin, 1 clonal male).
Each group will be represented by 15 fish in 4 replicate tanks (1m3), equating to 60 fish per group. In this experiment, fish will undergo an infestation challenge, whereby copepodids (30 per fish) will be introduced to the tanks and allowed to attached to potential hosts. Behaviour will be observed and quantified during the challenge, and subsequent lice loads will be assessed 3 days post-infestation. The source of distress is considered mild and likely to come from being infested with salmon lice, which will last through the 1 hour infestation challenge and the following 3 days before sampling.
By comparing different species of salmonids, the scientific benefit will be to further our understanding of host-parasite interactions and provide the basis for further research into factors that drive susceptibility, or alternatively, resistance to salmon lice. By including clonal lines, we will be able to determine the variance in infection parameters (infestation level, aggregation, variation within tank replicates) and partition infestation success between extrinsic (behaviour, group size) vs intrinsic (i.e. genetic background) factors. The proposed number of animals has been considering with ethical aims of reduction and replacement, and suggestions for improvements will be explored.
Each group will be represented by 15 fish in 4 replicate tanks (1m3), equating to 60 fish per group. In this experiment, fish will undergo an infestation challenge, whereby copepodids (30 per fish) will be introduced to the tanks and allowed to attached to potential hosts. Behaviour will be observed and quantified during the challenge, and subsequent lice loads will be assessed 3 days post-infestation. The source of distress is considered mild and likely to come from being infested with salmon lice, which will last through the 1 hour infestation challenge and the following 3 days before sampling.
By comparing different species of salmonids, the scientific benefit will be to further our understanding of host-parasite interactions and provide the basis for further research into factors that drive susceptibility, or alternatively, resistance to salmon lice. By including clonal lines, we will be able to determine the variance in infection parameters (infestation level, aggregation, variation within tank replicates) and partition infestation success between extrinsic (behaviour, group size) vs intrinsic (i.e. genetic background) factors. The proposed number of animals has been considering with ethical aims of reduction and replacement, and suggestions for improvements will be explored.