Anthropologic climate stress events are increasing in frequency and severity, threatening marine environments. Increased temperatures alter habitats of aquatic species, who cope by shifting their ranges poleward to more suitable conditions, referred to as tropicalisation. However, resulting changes in species distributions, trait compositions, and biomass are variable, with uncertainties remaining around primary drivers of these changes. We aim to characterise communities’ changes in biomass, trait composition, and thermal affinity using fish biomass records from 2010-2023 across 33 eastern Australian sites. We use principal component analyses to identify species contributing the most to biomass changes and traits composition changes. The community thermal affinity is characterised by computing communities thermal indexes from species thermal mid-points weighted by the mean biomasses. Finally, we use generalised linear mixed models to quantify environmental variables (SST, and PAR) contribution to the observed changes. We discover that tropicalisation patterns are highly correlated with inter-annual thermal signatures. Distinct tropical and warm-temperate species are found to have progressed poleward more rapidly than others, as warmer winters become more frequent. Our results highlight the importance of integrating traits and abundance of time series data to better detect, predict, and protect marine communities.