Trait similarity in reef fish faunas across the world’s oceans

Significance Biogeography has focused extensively on species identities, yet global patterns in species traits (morphological, physiological, or behavioral features) are not well known, including whether they are shaped by modern environmental conditions or by shared evolutionary history. Our global analysis of nearly 3,000 reef fish species found a consistent variety of traits across ocean basins worldwide, including a backbone of 21 trait combinations common to all oceans. At the regional scale, we found that fish assemblages in similar environments had similar trait compositions despite being separated by up to 100 degrees of latitude and hosting different species with distinct evolutionary histories. Thus, environmental conditions have likely shaped global patterns in reef fish traits regardless of geography, species identity, or evolutionary history.