Trait groups as management entities in a complex, multi-species reef fishery.

Localised stressors compound the ongoing climate-driven decline of coral reefs, requiring natural resource managers to work within rapidly shifting paradigms. Trait-based adaptive management (TBAM) is a new framework to help address changing conditions by choosing and implementing management actions specific to species groups that share key traits, vulnerabilities, and management responses. TBAM balances maintenance of functioning ecosystems with provisioning for human subsistence and livelihoods. We first identified trait-based groups of food fish in a Pacific coral reef with hierarchical clustering. Positing that trait-based groups performing comparable functions respond similarly to both stressors and management actions, we ascertained biophysical and socio-economic drivers of trait-group biomass and evaluated their vulnerabilities with generalised additive models. Clustering identified seven trait groups from 131 species. Groups responded to different drivers and displayed divergent vulnerabilities, with human activities emerging as important predictors of community structuring. Biomass of small, solitary reef-associated species increased with distance from key fishing ports, and large, solitary piscivores exhibited a decline in biomass with distance from a port. Group biomass also varied in response to different habitat types, the presence or absence of reported dynamite fishing activity and wave energy exposure. The differential vulnerabilities of trait groups reveal how food fish community structure is driven by different aspects of resource use and habitat. This inherent variability in the responses of trait-based groups presents opportunities to apply selective trait-based adaptive management strategies for complex, multi-species fisheries. This approach can be widely adjusted to suit local contexts and priorities.