What, when and where to eat? - Links between harbour porpoises and their prey provides knowledge for improved marine management

In 2020, Sweden was criticized by the European Commission for failing to comply with obligations under EU law to protect the threatened harbour porpoise.

Efficient conservation actions are urgently needed to stop continued population decrease and to prevent extinction of the species in the Baltic Proper.

However, conservation of porpoises is challenging and comes with inherent conflicts of interest with human activities, such as fisheries, shipping and coastal exploitation. To protect the remaining populations knowledge of the diet and habitat use of porpoises in Swedish waters is needed.

In this project, we provide stakeholders with requested scientific research and advice to allow implementation of ecosystem-based management actions where both porpoise conservation and human activities are considered.

We provide a thorough picture of the diet of porpoises in Swedish waters, and explore potential links between diet composition and changes in fish populations and porpoise health.

To investigate drivers for habitat use, the fine-scale spatiotemporal distribution and foraging behaviour of porpoises is monitored during two years in combination with relevant environmental variables and interactions with prey.

Ultimately, this allow us to describe how porpoises interact with their ecosystem and identify important environmental variables that can be incorporated into a model and used to predict important areas in space and time for harbour porpoises in Swedish marine waters.