The impact of climate change on infection of salmonid fish with Saprolegnia

Fish are very sensitive to changes in their environment and it is known that such changes can lead to increased stress and can alter the immune status of the fish, which in turn can lead to higher susceptibility to diseases. We will investigate the role of water temperature and oxygen changes on the incidence and severity of salmon and trout infection with Saprolegnia parasitica and Saprolegnia diclina. Both pathogens cause saprolegniosis, which is a deadly disease of salmonid eggs and fish. Saprolegniosis can often lead to losses of 10% or more in fish farms. Currently these oomycete pathogens rank amongst the top 3 of most relevant pathogens on rainbow trout and Atlantic salmon in the aquaculture industry of the UK.
Data on temperature and oxygen dependant pathogen dynamics and host immune response will be collected through experimental and field studies, which will provide a basis for predicting the likely impact of these pathogens as a result of climate change. Spatial analysis and mapping techniques will be used to identify baseline relationships between fish farm locations, environmental conditions in the river and pathogen abundance. Based on climate change predictions for the UK, we will try to predict how the impact of the pathogens in our study is likely to change over the next decades. The information generated from this project, which addresses all priority areas of the BBSRC/NERC joint call on Aquaculture: Fish Health & Disease, will ultimately allow better planning and design of mitigating strategies for farmers, which will be especially relevant after the enforcement of the EU-wide ban on the use of formalin in aquaculture. Changes in aquaculture management procedures, biosecurity and treatment (of intake water or fish) may allow fish farmers to counteract some of the expected impacts of these fish pathogens in response to climate change. The project will also allow making projections about the impact of CC and Saprolegnia infection on wild salmonid fish. This information will be important to inform future conservation strategies.

Fish are very sensitive to changes in their environment and it is known that such changes can lead to increased stress and can alter the immune status of the fish, which in turn can lead to higher susceptibility to diseases. We will investigate the role of water temperature and oxygen changes on the incidence and severity of salmon and trout infection with Saprolegnia parasitica and Saprolegnia diclina.
Data on temperature and oxygen dependant pathogen dynamics and host immune response will be collected through experimental and field studies, which will provide a basis for predicting the likely impact of these pathogens as a result of climate change. We will develop a new real time-PCR quantification method to determine the number of zoospores in water and mucous of the fish. Furthermore, detailed gene expression analysis of known (pro)-inflammatory, immunological and stress-induced genes will be performed in head kidney, spleen and gill samples. Spatial analysis and mapping techniques will be used to identify baseline relationships between fish farm locations, environmental conditions in the river and pathogen abundance. Based on climate change predictions for the UK, we will try to predict how the impact of the pathogens in our study is likely to change over the next decades. The information generated from this project will ultimately allow better planning and design of mitigating strategies for farmers, which will be especially relevant after the enforcement of the EU-wide ban of the use of formalin in aquaculture. Changes in aquaculture management procedures, biosecurity and treatment (of intake water or fish) may allow fish farmers to counteract some of the expected impacts of these fish pathogens in response to climate change. The project will also allow making projections about the impact of climate change and Saprolegnia infection on wild salmonid fish. This information will be important to inform future conservation strategies.

Who will benefit from this research?

(1) Pharmaceutical, biotechnology industries, the aquaculture industry (fish farmers), anglers, conservation organisations
How will they benefit?
With the proposed project we will provide novel knowledge on the Saprolegnia-host interaction in response to climate change, in particular diagnostics and quantification of pathogen spore levels in water, pathogenicity and host defence responses that will ultimately lead to control measures that are currently not available.
The results of our study will not only allow insights on the impact of CC on farmed salmonid species. Wild Atlantic salmon, brown trout and other salmonid species living in rivers in the UK are going to be exposed to the impact of CC as are farmed salmonids. The insights about how well salmonid species are capable of coping with CC associated environmental changes will allow making projections about the likely impact of CC associated water temperature changes in the future. The information generated under this project is likely to help future planning of conservation strategies.

What will be done to ensure that they have the opportunity to benefit?
We will communicate our research and results to colleagues and industry through our publications in the literature, through presentation at appropriate scientific meetings, and by making reagents generated as part of this project available to other researchers under structured material transfer agreements. We will take advantage of natural liaison opportunities that emerge from our membership of NERC and BBSRC Networks. We will also work together with the Research and Innovation unit at the University of Aberdeen and Cefas to identify findings that have clear potential for commercial exploitation. We will actively get fish farmers informed about our findings by giving seminars for fish farm health managers. The PI is giving such seminars on an annual basis at several companies (eg Marine Harvest, Landcatch, Novartis, Zoetis and MSD)

(2): The public
How will they benefit?
The general public will benefit from this research in a number of ways because our work will ultimately safeguard food production. We will however ensure that the public is informed about our research, forming part of a national effort by the science community to ensure greater scientific literacy among the general population.

What will be done to ensure that they have the opportunity to benefit?
Ensuring public awareness of our research and allowing a public education impact to be made, we will use our groups' web sites to communicate our science to the public. Key research outcomes from this proposal will be released by the University of Aberdeen's Communication sections as press releases.


(3) Policy makers and (non)-government bodies
How will they benefit?
Legislators and (non)-government bodies involved in wildlife conservation in UK and fish farming (such as Natural Heritage, DEFRA, SEPA, Scottish Salmon Producing Organisation, the British Trout Association etc.) will be able to use our generated data to better predict and avoid possible Saprolegnia parasitica outbreaks in the UK. In case we obtain clear evidence that climate change plays a major part in increased problems of saprolegniosis in salmonids, we would consult with legislators, relevant organisations and other policy makers across the UK to find solutions to minimize saprolegniosis in fish.

What will be done to ensure that they have the opportunity to benefit?
We already have good links with several representatives of these organisations and will actively approach them to consider our results.