Widespread diversity deficits of coral reef sharks and rays

A global survey of coral reefs reveals that overfishing is driving
resident shark species toward extinction, causing diversity deficits in
reef elasmobranch (shark and ray) assemblages. Our species-level analysis
revealed global declines of 60 to 73% for five common resident reef shark
species and that individual shark species were not detected at 34 to 47%
of surveyed reefs. As reefs become more shark-depleted, rays begin to
dominate assemblages. Shark-dominated assemblages persist in wealthy
nations with strong governance and in highly protected areas, whereas
poverty, weak governance, and a lack of shark management are associated
with depauperate assemblages mainly composed of rays. Without action to
address these diversity deficits, loss of ecological function and
ecosystem services will increasingly affect human communities.