Harbor porpoise Freja is a key to unlocking the secrets of her species. At 30 years old, she is the oldest recorded harbor porpoise in the world and has lived in a Danish research facility since being by-caught in a fishing net in 1997 and deemed non-releasable. Since then, she has contributed to non-invasive research that helps scientists study one of Europe’s most elusive and threatened marine mammals.

Despite inhabiting the North and Baltic Seas, harbor porpoises (Phocoena phocoena) remain difficult to study in the wild. Since 2020, they have been classified as critically endangered on the German Red List of species, with populations sharply declining populations. Annually, around 600 and 1,000 strandings are reported across western Europe. In response, institutions across Denmark, the Netherlands, and Germany have formed an alliance with the aim to protect the species before it vanishes.

SOS Dolfijn, the only European non-profit dedicated to porpoise rehabilitation, plays a central role. Since its foundation in 2004, the organization has rescued over 150 porpoises. Patients offer rare insights into porpoise physiology, while highlighting the importance of hands-on care and long-term data collection.

Elsewhere, research institutions are tracking the broader pressures facing the species. Utrecht University investigates causes of death – such as by-catch, pollution, and ship noise – through systematic necropsies. Wageningen University analyzes fish ear bones (otoliths) in porpoise stomachs to study overfishing. The Rugvin Foundation explores how porpoise feces may contribute to phytoplankton growth, suggesting a deeper ecological role within marine nutrient cycles.

The harbor porpoise is considered an indicator species: its health reflects the condition of the seas it inhabits – and, by extension, our own. Rising strandings, habitat disruption, and unsustainable fishing practices signal an ecosystem under pressure. Conservation efforts, like acoustic deterrents tested by the German Oceanographic Museum or ghost-net retrievals by GRD divers, aim to reduce these risks.

Though small, elusive, and often overlooked, the harbor porpoise stands at the intersection of environmental, scientific, and political urgency. This project follows the networks working to safeguard its future – and reveals what its fate tells us about the health of our oceans and ourselves.