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Overexploitation is recognized as one of the main threats to global biodiversity. Here, we report a widespread change in the functional diversity of fisheries catches from the large marine ecosystems (LMEs) of the world over the past 65 years (1950 to 2014). The spatial and temporal trends of functional diversity exploited from the LMEs were calculated using global reconstructed marine fisheries catch data provided by the Sea Around Us initiative (including subsistence, artisanal, recreational, industrial fisheries, and discards) and functional trait data available in FishBase. Our analyses uncovered a substantial increase in the functional richness of both ray-finned fishes (80% of LMEs) and cartilaginous species (sharks and rays) (75% of LMESs), in line with an increase in the taxonomic richness, extracted from these ecosystems. The functional evenness and functional divergence of these catches have also altered substantially over the time span of this study, with considerable geographic variation in the patterns detected. These trends show that global fisheries are increasingly targeting species that play diverse roles within the marine ecosystem and underline the importance of incorporating functional diversity in ecosystem management.

Biotic responses to global change include directional shifts in organismal traits. Body size, an integrative trait that determines demographic rates and ecosystem functions, is thought to be shrinking in the Anthropocene. Here, we assessed the prevalence of body size change in six taxon groups across 5025 assemblage time series spanning 1960 to 2020. Using the Price equation to partition this change into within-species body size versus compositional changes, we detected prevailing decreases in body size through time driven primarily by fish, with more variable patterns in other taxa. We found that change in assemblage composition contributes more to body size changes than within-species trends, but both components show substantial variation in magnitude and direction. The biomass of assemblages remains quite stable as decreases in body size trade off with increases in abundance.