Regulatory language limits satellite-based enforcement in marine protected areas

Abstract The international community has committed to protect 30% of the ocean by 2030, and satellite monitoring can now detect industrial fishing inside marine protected areas (MPAs) at near-global scale. Yet remote detection establishes only a vessel’s identity, position, time, and movement; whether those facts can support enforcement action depends on how the law is written. We analysed the regulatory text of 9740 MPA zones and 119 national legal instruments across 15 countries. A Regulation Preparedness Index shows that MPA rules are rarely drafted in terms that remote evidence can prove: the mean score is 33 of 100, 61% of zones contain discretionary language, and only 4% refer to vessel monitoring or satellite systems. A screening of national legislation for evidentiary, penalty, enforcement, technology, and liability provisions gives a mean of 47 of 100, and no country scores above 50 on both layers. Rewriting rules as spatially explicit, unconditional prohibitions with vessel-tracking and reporting obligations would more than double the mean index (to 76), an index-internal upper bound that requires formal amendment but no new technology. We set out the drafting elements that make satellite detections actionable, in coastal waters and under the new high seas treaty.