To assess the effectiveness of marine protected areas and fish behaviour, scientists measured ‘flight distance’ in a range of coral reef fishes in Papua New Guinea. ‘We were studying the effect of customary reef closures which many groups in the Pacific use,’ explains Fraser Januchowski-Hartley of the ARC Centre of Excellence for Coral Reef Studies at James Cook University and the Wildlife Conservation Society. Local chiefs close areas of reef to fishing whenever fish become shy. Fish regularly targeted had a fair idea of speargun range and stayed further away. When an area was closed, the fish recovered confidence, allowing divers to approach closer. While temporary closures have value, their effect on fish behaviour may have to be factored in when reserves are reopened. This may entail the use of gear-restrictions or short re-openings.