The energetic consequence of salmon lice infestations
Parasites will assert an increased energetic cost to the host organism, and depending on infestation levels this may compromise key physiological functions that consequently can reduce the fitness of the host. In this experiment we wish to quantify the metabolic costs associated with salmon lice infestations in newly smoltified Atlantic salmon. Salmon lice are thought to pose a significant threat to wild salmonids and are presently the greatest health issue in salmon aquaculture in Norway. However, few studies have focused on sub-lethal physiological effects of sea lice to better understand their ecological implications for the host. By measuring whole-animal metabolic rates of fish with varying parasite loads, we will here be able to reveal the precise energetic burden of coping with sea lice infestations in Atlantic salmon. The severity and consequence of a particular parasite load can then be interpreted in a more nuanced ecological context.
The fish used in this study will be experimentally infected with salmon lice in either low amounts (~0.3 lice/g) or high amounts (>1 lice/g). The metabolic rates of the fish will then be measured by using a static respirometry system. Metabolic rates will be measured both in the early phase (chalimus 1 stage) and later on when effects are expected to be more serious (pre-adult 1 stage). Moreover, a control group of uninfected fish will also be measured with respirometry. The fish used in this study will experience some distress owing to infection of sea lice, as well as brief acute handling stress associated with the respirometry protocol.
The expected outcome of this work is novel insights into the fundamental physiology of Atlantic salmon in response to sea lice infestations. Moreover, this fundamental research will improve our understanding of the ecology in wild fish, and ultimately help us provide more nuanced risks assessments of the environmental impact of sea lice dispersal from salmon cages in Norway. Finally, the knowledge gained here also has relevance for fish welfare legislations in salmon aquaculture.
In total we will be testing 80 Atlantic salmon.
Regarding the 3R’s; replacement is not possible as we are investigating complex whole-organismal effects in an experimental parasite/host model. Reduction of animal used in the experimental design has been optimized with regards to number of treatment groups and replication level to ensure robust and valid results, based on our extensive previous experiences with similar methodologies. Refinement is considered in all aspects of the experimental protocols to prevent and minimize unnecessary handling stress. Moreover, fish will be kept in a controlled tank laboratory facility under a careful animal husbandry practice.
The fish used in this study will be experimentally infected with salmon lice in either low amounts (~0.3 lice/g) or high amounts (>1 lice/g). The metabolic rates of the fish will then be measured by using a static respirometry system. Metabolic rates will be measured both in the early phase (chalimus 1 stage) and later on when effects are expected to be more serious (pre-adult 1 stage). Moreover, a control group of uninfected fish will also be measured with respirometry. The fish used in this study will experience some distress owing to infection of sea lice, as well as brief acute handling stress associated with the respirometry protocol.
The expected outcome of this work is novel insights into the fundamental physiology of Atlantic salmon in response to sea lice infestations. Moreover, this fundamental research will improve our understanding of the ecology in wild fish, and ultimately help us provide more nuanced risks assessments of the environmental impact of sea lice dispersal from salmon cages in Norway. Finally, the knowledge gained here also has relevance for fish welfare legislations in salmon aquaculture.
In total we will be testing 80 Atlantic salmon.
Regarding the 3R’s; replacement is not possible as we are investigating complex whole-organismal effects in an experimental parasite/host model. Reduction of animal used in the experimental design has been optimized with regards to number of treatment groups and replication level to ensure robust and valid results, based on our extensive previous experiences with similar methodologies. Refinement is considered in all aspects of the experimental protocols to prevent and minimize unnecessary handling stress. Moreover, fish will be kept in a controlled tank laboratory facility under a careful animal husbandry practice.