Impacts of climate-related stressors to Atlantic cod health and welfare
1. Purpose
The trial described in this application aims to understand how climate-related stressors, specifically a heatwave and elevated levels of carbon dioxide (CO2), impact Atlantic cod (Gadus morhua) health and welfare.
2. Distress
Atlantic cod juveniles will be exposed to two environmental stressors (i.e. heatwave and elevated CO2) alone or in combination. After the recovery period, a group of fish will be subjected to a stress test (i.e., crowding) to evaluate the ability of fish to respond to a secondary stressor.
3. Expected benefit
The proposed trial will provide experimental evidence of the impact of climate-related stressors to Atlantic cod. This will be crucial in developing climate - risk and - adaptation plans for Norwegian fisheries and aquaculture. Data from the trial will also provide new insights into cod biology, and will contribute to biological knowledge that will assist the reemergence of cod framing in Norwegian aquaculture.
4. Number of animals and what kind
Six hundred sixty (660, appr. 70 g at the beginning) mixed-sex Atlantic cod are intended to be used in the trials described in this application.
5. How to adhere to 3R
There is no other way to test the hypothesis in the study than performing a trial using live fish, nevertheless, we incorporated several strategeies to reduce fish number and reduce distress to the fish. First, we will be using the remaining fish at the research station that would otherwise be discarded. Second, the heatwave protocol and CO2 level was based on a previous trial and published study. Third, we combined the hypotheses of two independent projects, thus running one fish trial instead of two. Lastly, humane endpoints are clearly defined and, the experimental systems are designed for optimal rearing conditions for cod under captivity.
The trial described in this application aims to understand how climate-related stressors, specifically a heatwave and elevated levels of carbon dioxide (CO2), impact Atlantic cod (Gadus morhua) health and welfare.
2. Distress
Atlantic cod juveniles will be exposed to two environmental stressors (i.e. heatwave and elevated CO2) alone or in combination. After the recovery period, a group of fish will be subjected to a stress test (i.e., crowding) to evaluate the ability of fish to respond to a secondary stressor.
3. Expected benefit
The proposed trial will provide experimental evidence of the impact of climate-related stressors to Atlantic cod. This will be crucial in developing climate - risk and - adaptation plans for Norwegian fisheries and aquaculture. Data from the trial will also provide new insights into cod biology, and will contribute to biological knowledge that will assist the reemergence of cod framing in Norwegian aquaculture.
4. Number of animals and what kind
Six hundred sixty (660, appr. 70 g at the beginning) mixed-sex Atlantic cod are intended to be used in the trials described in this application.
5. How to adhere to 3R
There is no other way to test the hypothesis in the study than performing a trial using live fish, nevertheless, we incorporated several strategeies to reduce fish number and reduce distress to the fish. First, we will be using the remaining fish at the research station that would otherwise be discarded. Second, the heatwave protocol and CO2 level was based on a previous trial and published study. Third, we combined the hypotheses of two independent projects, thus running one fish trial instead of two. Lastly, humane endpoints are clearly defined and, the experimental systems are designed for optimal rearing conditions for cod under captivity.
Etterevaluering
The Norwegian Food Safety Authority must retrospectively assess all severe experiments.
Begrunnelse for etterevalueringen
The experiment simulated climate-related scenarios expected to be encountered by Atlantic cod under the current climate prediction models. This seems to be one of the first studies where combination of climate stressors was studied instead of studying them as individual stressors.
Preliminary data indicated that heat waves might have a stronger impact on cod immunity than acidification. The trials provided evidence about the compound effect of climate-related stress. This information will be important for climate adaptation plans.
The study utilised 660 animals. During the trial 165 cod were subjected to mild distress, 330 to moderate and 165 to severe distress.
In-vitro models are currently being developed by the research group, and this trial was used to validate these models.
Due to combination of the hypotheses from two projects into one trial, the number of fish for research in this trial were substantially reduced. However, the researchers believe power calculation in climate research studies should be discussed too, as this may facilitate further reduction of fish.
Improvements to reduce the distress in use of harmful procedures in future trials, are the use of shorter heat waves. Moreover, sensitive sensors must be purchased to have more extensive monitoring of the fish and their rearing conditions during the experimental period.
Preliminary data indicated that heat waves might have a stronger impact on cod immunity than acidification. The trials provided evidence about the compound effect of climate-related stress. This information will be important for climate adaptation plans.
The study utilised 660 animals. During the trial 165 cod were subjected to mild distress, 330 to moderate and 165 to severe distress.
In-vitro models are currently being developed by the research group, and this trial was used to validate these models.
Due to combination of the hypotheses from two projects into one trial, the number of fish for research in this trial were substantially reduced. However, the researchers believe power calculation in climate research studies should be discussed too, as this may facilitate further reduction of fish.
Improvements to reduce the distress in use of harmful procedures in future trials, are the use of shorter heat waves. Moreover, sensitive sensors must be purchased to have more extensive monitoring of the fish and their rearing conditions during the experimental period.