Scientists have investigated two remote coral atolls in the Pacific Ocean where nature has remained largely untouched by human activity. These are the Bikar and Bokak atolls in the Marshall Islands, which have been declared the country's first national marine reserve.
New research published in the journal Frontiers in Marine Science indicates that Bikar and Bokak are among the best-preserved marine ecosystems in the region. The scientists analysed data collected during a 2023 expedition, during which they examined life on land, coral reefs and in the deep sea in detail.
Bikar is located approximately 116 kilometres from the nearest inhabited atoll, while Bokak is roughly 385 kilometres away from the closest inhabited atoll. The research was led by Alan Friedlander, a marine ecologist from the University of Hawaii.
During the study, scientists recorded at least 266 groups of reef fish from 38 families, finding a higher total fish biomass at Bokak. On the outer parts of the coral reefs, sharks accounted for 26.8 per cent of the fish biomass at Bikar and 33.9 per cent at Bokak.
Researchers used submersibles to study life at depths of up to 275 metres. There, they recorded 138 groups of fish, including 14 groups previously unrecorded in the Marshall Islands. Cameras placed at even greater depths revealed an additional 79 groups of fish.
The atolls also hosted 17 species of seabirds and large nesting colonies. The team found 71 sea turtle tracks on the beaches and 132 depressions dug by turtles for laying eggs, with the majority of these tracks and depressions located at Bikar. During the expedition, scientists also discovered that introduced Polynesian rats live on both atolls.
The atolls face global threats such as ocean warming, coral bleaching and ocean acidification. After Bokak, the scientists visited Bikini Atoll, where the United States conducted nuclear tests in the mid-20th century. The explosions destroyed three islands and left radioactive contamination, rendering Bikini uninhabited to this day.
In 2025, the first national marine protected area in the country was declared around the Bikar and Bokak atolls. The protected area covers approximately 48,000 square kilometres of ocean.
