Beyond catch location, individual fish traits add little predictive power for DDX and PCBs in Southern California sport fishes

Legacy contaminants (DDX and PCBs) persist in fishes of the Southern California Bight, yet most consumption advisories rely on species- and region-level averages that ignore within-species variation among harvested individuals. We evaluated whether individual traits improve prediction of contaminant burden in a "fish in hand," and whether any gains can be achieved using information available to anglers at capture (e.g., size, region) versus traits requiring post-hoc laboratory analysis (e.g., age, stable-isotope-inferred trophic ecology). Using individually sampled, angler-caught fish collected across the Southern California Bight with associated metadata, we compared five nested predictive frameworks of increasing complexity, from species alone to models adding region, angler-measurable traits (length, lifestyle), spatially explicit sediment-contamination estimates, and laboratory-derived age and trophic-isotope metrics. Region - when informed by underlying sediment contaminant burden maps - substantially improved predictions of individual contaminant concentrations, whereas fish length contributed little additional predictive power. Among laboratory-assessed traits, isotope-derived trophic ecology provided the largest improvement, but gains were modest relative to location-based models. Overall, our results indicate limited potential for individual traits beyond catch location to meaningfully refine advisories, and support place-based guidance that leverages spatial contaminant prediction tools to inform safer consumption of recreationally caught fish.