Age dependent infectivity of salmon lice (L. salmonis) copepodids
The infectivity of L. salmonis copepodids is not constant throughout the stage (Frenzl et al. 2014).
This may significantly impact on the way salmon louse infestation pressure should be modelled and models parameterized. Unfortunately the sparse data available is difficult to combine into a coherent overview as procedures and approaches varies between studies. In the present experiment we will generate a dataset investigating the salmon louse copepodids infectivity at seven selected timepoints after emergence. The experiment will be repeated at three temperatures encompassing a realistically encountered temperature range (5-15 dregrees).
Each group will be represented by 10 fish in 4 replicate tanks (1m3), equating to 40 fish per treatment. 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. Subsequent lice loads will be assessed at the first chalimus stage - 6-12 days post-infestation dependent on temperature. 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 6-12 days before sampling.
The results will allow us to understand how salmon louse copepodid infectivity varies with senescence. The results are likely to have impact on infectivity modelling and hence on the aquaculture management regime.
The experiments will involve a total of 840 Atlantic salmon (Salmo salar). The number of fish and tanks used are based on a combination of the desired temporal data resolution and experience with infection trials from previous experiments.
This may significantly impact on the way salmon louse infestation pressure should be modelled and models parameterized. Unfortunately the sparse data available is difficult to combine into a coherent overview as procedures and approaches varies between studies. In the present experiment we will generate a dataset investigating the salmon louse copepodids infectivity at seven selected timepoints after emergence. The experiment will be repeated at three temperatures encompassing a realistically encountered temperature range (5-15 dregrees).
Each group will be represented by 10 fish in 4 replicate tanks (1m3), equating to 40 fish per treatment. 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. Subsequent lice loads will be assessed at the first chalimus stage - 6-12 days post-infestation dependent on temperature. 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 6-12 days before sampling.
The results will allow us to understand how salmon louse copepodid infectivity varies with senescence. The results are likely to have impact on infectivity modelling and hence on the aquaculture management regime.
The experiments will involve a total of 840 Atlantic salmon (Salmo salar). The number of fish and tanks used are based on a combination of the desired temporal data resolution and experience with infection trials from previous experiments.