Johanna Marcussen is a coastal ecologist at the Institute of Marine Research and the University of Agder, studying the intersection between people and the sea. Her research explores coastal shellfish and recreational fisheries, asking how much we have, how much we can sustainably harvest, and how much recreational fishing shapes the picture.

Her work has uncovered just how important missing data can be. More than 30,000 recreational fishers may account for up to 90% of Norway’s lobster catch, yet much of this activity has historically been difficult to capture in stock assessments.

Johanna is also passionate about making ocean science accessible. She serves on Norway’s national committee for the UN Ocean Decade, runs Lei en biolog, organises Barnas havfest, and won Norway’s national Forsker Grand Prix in 2025.

She has lived aboard her sailboat for the past ten years, so for Johanna, the ocean is both her research field and her home.

At TEDxArendal, she invites us to consider how the things we don’t see in the data can change what we think we know.