Trait‐based ecology of fishes: A quantitative assessment of literature trends and knowledge gaps using topic modelling

Species traits are a new data currency to enhance our understanding of ecological patterns and processes. Trait‐based studies of fishes are numerous in comparison with other animal groups, reflecting the diversity of fish forms and functions they provide to aquatic ecosystems. We conduct a retrospective examination of literature to identify knowledge gaps and provide guidance for future research in trait‐based fish ecology. We apply an automated text mining and topic modelling to track the evolution of research topics within peer‐reviewed articles of functional traits in marine and freshwater fishes published over the past half century, explore the inter‐connections among those topics and identify emerging avenues for investigation. By mapping the topic landscape of the literature, 16 latent topics emerged that vary in their prevalence. Our results show a decline in the frequency of studies using reproductive traits to model and explore the way fish allocate energy for reproduction, and increase in studies reporting functional diversity metrics and utilizing the concept of multivariate functional space. Research focused on contributions of fish traits to ecosystem functioning also has increased in frequency. We revealed large gaps in information between growing and decreasing topics and that these gaps were derived from different types of traits being considered. We suggest that scientists break‐free from the traditions of their research field by targeting investigations that: (a) apply functional diversity metrics to a broader assortment of traits, (b) focus on traits influencing energy allocation to growth/reproduction and (c) integrate trophic‐web and behavioural studies with other topics.