Remote Pacific Islands Offer a Vital Refuge for Sharks as Coastal Stocks Dwindle

New research paints a contrasting picture of marine life in the Tropical Eastern Pacific. By deploying baited video cameras known as stereo-BRUVs across seven Marine Protected Areas (MPAs), scientists have uncovered a stark divide between remote oceanic islands and reserves closer to the continental coast.

The study found that remote oceanic MPAs are flourishing, boasting significantly higher species richness and abundance across the food chain. In fact, these isolated reefs support some of the highest relative abundances of sharks recorded globally. This biological wealth is attributed to nutrient-rich ocean currents and the natural protection offered by their extreme remoteness, which limits human interference.

Conversely, coastal MPAs tell a worrying tale of depletion. In areas such as the coastal waters of Ecuador, fish numbers were low at every level of the ecosystem. Most alarmingly, large predators were notably absent, a phenomenon often described as ‘fishing down the food web’—where top-tier species are removed, destabilising the ecosystem structure.

The findings highlight that while designating an area as protected is a crucial first step, it is not a silver bullet. The researchers argue that without rigorous enforcement and impact assessments to curb fishing pressure, even protected coastal biodiversity remains at risk. These remote islands act as vital modern refuges, but coastal zones require urgent intervention to recover.