This study investigates the baseline conditions and degradation of coral reefs in the northern Line Islands to assess the impacts of human activities and evaluate management effectiveness. The researchers surveyed uninhabited atolls like Kingman and Palmyra, which are relatively undisturbed, and increasingly populated atolls like Tabuaeran and Kiritimati, to document changes associated with human activities. They found that top predators and reef-building organisms dominated the unpopulated atolls, while small planktivorous fishes and fleshy algae were more prevalent on the populated atolls. Sharks and other top predators were abundant on Kingman and Palmyra, leading to an inverted biomass pyramid, whereas the biomass pyramid at Tabuaeran and Kiritimati was typical and bottom-heavy. Reefs without human presence exhibited less coral disease and greater coral recruitment compared to more inhabited reefs. The results suggest that protection from overfishing and pollution enhances the resilience of reef ecosystems to global warming. The study highlights the importance of ecological baselines for conservation and restoration efforts.This study investigates the baseline conditions and degradation of coral reefs in the northern Line Islands to assess the impacts of human activities and evaluate management effectiveness. The researchers surveyed uninhabited atolls like Kingman and Palmyra, which are relatively undisturbed, and increasingly populated atolls like Tabuaeran and Kiritimati, to document changes associated with human activities. They found that top predators and reef-building organisms dominated the unpopulated atolls, while small planktivorous fishes and fleshy algae were more prevalent on the populated atolls. Sharks and other top predators were abundant on Kingman and Palmyra, leading to an inverted biomass pyramid, whereas the biomass pyramid at Tabuaeran and Kiritimati was typical and bottom-heavy. Reefs without human presence exhibited less coral disease and greater coral recruitment compared to more inhabited reefs. The results suggest that protection from overfishing and pollution enhances the resilience of reef ecosystems to global warming. The study highlights the importance of ecological baselines for conservation and restoration efforts.