The benefits of protected areas depend on compliance, and achieving protection remains a challenge in intensely used areas where conservation and socioeconomic goals are in real or apparent conflict. One recent innovation - satellite tracking of commercial fishing vessels - has been introduced to help with ocean protection initiatives and build trust between fishers and managers. We paired vessel traffic data before and during a temporary closure in the Adriatic Sea with data on fish nursery habitat to examine changes in fishing effort and their potential consequences. Trawlers generally complied with the closure but maintained overall effort by trawling more intensely outside of the no-trawl zone, especially near its borders and closer to shore. We detected stronger than expected fishing effort in a sub-region within the protected area, suggesting that this location should be closely monitored for compliance. Notably, fishing effort was relocated to nursery grounds for some exploited species, illustrating the importance of understanding species' life histories and habitat distribution in the design of protected areas.