How functionally diverse are fish in the deep? A comparison of fish communities in deep and shallow‐water systems

Aim: Functional diversity metrics inform how species’ traits relate to ecosystem functions, useful for quantifying how exploitation and disturbance impact ecosystems. We compare the functional diversity of entire fish communities in a shallow-water region with a deep-sea region for further insight into the differences between these ecosystem types. Location: The regions compared in this study were selected to represent a shallow-water coastal region, Tasman and Golden Bays (TBGB), and a deep-sea region, Chatham Rise (CR), in New Zealand. Methods: Functional diversity was assessed using four metrics: functional richness, evenness, divergence, and dispersion. We compared these metrics across four key functions: habitat use, feeding, locomotion and life history. Results: Our results showed that overall, the shallow-water and deep-sea ecosystems had equal diversity. When focusing on the four ecological functions, the two ecosystems exhibited equal diversity metrics across most anal...