Catchability of harbour porpoises in a Northern Norwegian fjord
• Purpose of the experiment,
We plan to actively capture and release wild free-ranging harbour porpoises (hp) in order to ultimately instrument them with satellite-linked tags and collect biological samples. Two main capture methods exist, however, their success depend on the animals’ behaviour and the local environment.
The main purpose of this application is therefore to develop the “best practice” for capturing, handling and releasing free-ranging hp in Northern Norwegian fjords. Because this is a pilot project on catchability we directly address the refinement point in the list of the 3Rs.
• Expected distress for the animals,
The whole experiment is described as mild / minimal procedure as the stress and discomfort that will be experienced by the animals is short term, mild and will not significantly impair their well-being or their general condition. Indeed, the success of a tagging experiment (as we are planning in the future based on the results of the present pilot project) relies on the fact that the animals are not impaired upon release and behave as wild free-ranging animals.
• Expected scientific or societal benefit,
The hp is widely distributed in coastal and continental shelves areas of the North Atlantic. A range of anthropogenic disturbances such as noise and chemical pollution, pathogens and fisheries activities can severely affect harbour porpoises. There is little information on the health status of Norwegian hp and most comes from stranded or by-caught animals that are not representative of the population. As a top predator, the hp can be used as a coastal sentinel species reflecting the effects of human activities. However, a health baseline is first needed. In order to relate precisely individuals’ health status to an environmental stressor and its geographical source, it is essential to know the range of the animal’s movement and the geographical areas of high usage. This can be achieved using biotelemetry tools.
By-catch is the most prominent threat to hp through their distributional range and based on recent calculations, by-catch rates in Norway seem to be above sustainable levels. Therefore the incriminated fisheries do not comply with international regulations for fish export. Instrumented animals would give us insight on their behaviour in the vicinity of fishing nets and fishing activities.
• how many and what kind of animals to be used,
Groups of several animals will not be targeted, preference will be given to solitary animals, to avoid the risk of entanglement of several animals at the same time. Mother and calves groups will especially be avoided. Young calves will not be captured. Adults and juveniles male and female will preferably be sampled. We will catch a maximum of 10 individuals, this should be sufficient to ensure that our capture and handling protocols are safe and reliable.
• how demands for replacement, reduction and improvement will be adhered to.
This projects demands specifically the capture of harbour porpoises. Each capture will be filmed and reviewed afterwards in order to identify any point that can be improved and refined.
We plan to actively capture and release wild free-ranging harbour porpoises (hp) in order to ultimately instrument them with satellite-linked tags and collect biological samples. Two main capture methods exist, however, their success depend on the animals’ behaviour and the local environment.
The main purpose of this application is therefore to develop the “best practice” for capturing, handling and releasing free-ranging hp in Northern Norwegian fjords. Because this is a pilot project on catchability we directly address the refinement point in the list of the 3Rs.
• Expected distress for the animals,
The whole experiment is described as mild / minimal procedure as the stress and discomfort that will be experienced by the animals is short term, mild and will not significantly impair their well-being or their general condition. Indeed, the success of a tagging experiment (as we are planning in the future based on the results of the present pilot project) relies on the fact that the animals are not impaired upon release and behave as wild free-ranging animals.
• Expected scientific or societal benefit,
The hp is widely distributed in coastal and continental shelves areas of the North Atlantic. A range of anthropogenic disturbances such as noise and chemical pollution, pathogens and fisheries activities can severely affect harbour porpoises. There is little information on the health status of Norwegian hp and most comes from stranded or by-caught animals that are not representative of the population. As a top predator, the hp can be used as a coastal sentinel species reflecting the effects of human activities. However, a health baseline is first needed. In order to relate precisely individuals’ health status to an environmental stressor and its geographical source, it is essential to know the range of the animal’s movement and the geographical areas of high usage. This can be achieved using biotelemetry tools.
By-catch is the most prominent threat to hp through their distributional range and based on recent calculations, by-catch rates in Norway seem to be above sustainable levels. Therefore the incriminated fisheries do not comply with international regulations for fish export. Instrumented animals would give us insight on their behaviour in the vicinity of fishing nets and fishing activities.
• how many and what kind of animals to be used,
Groups of several animals will not be targeted, preference will be given to solitary animals, to avoid the risk of entanglement of several animals at the same time. Mother and calves groups will especially be avoided. Young calves will not be captured. Adults and juveniles male and female will preferably be sampled. We will catch a maximum of 10 individuals, this should be sufficient to ensure that our capture and handling protocols are safe and reliable.
• how demands for replacement, reduction and improvement will be adhered to.
This projects demands specifically the capture of harbour porpoises. Each capture will be filmed and reviewed afterwards in order to identify any point that can be improved and refined.