Evaluation of Lethal and Sublethal Effects of 6PPDQ on Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) (ver. 2.0, March 2025)

6PPD-Quinone (6PPDQ) was recently implicated in mass pre-spawn mortality events in adult coho salmon (Oncorhynchus kisutch) in the Pacific Northwest. Since then, studies have reported highly variable toxicity among fish species, including within the salmonids. This dataset explores the sensitivity of coastal cutthroat trout (Oncorhynchus clarkii clarkii) at three life stages: alevin, 5 mo. old parr, and 13 mo. old juveniles, and includes analytically measured concentrations for the exposures. In addition, 96-hour semi-static exposures and pulsed exposures were conducted in juvenile fish for comparison with the 24-hour toxicity and to mimic environmentally relevant storms, respectively. 24-hour sensitivity was also measured in juvenile coastal cutthroat trout from a different hatchery, and westslope cutthroat trout (Oncorhynchus clarkii lewisi) alevin and parr for comparison. We investigated two sublethal endpoints. After establishing a viral challenge model with infectious hematopoietic necrosis virus (IHNV) (Experiment 1), we measured virulence (mortality) and infection in 7 and 10 mo. old coastal cutthroat trout exposed to sublethal 6PPDQ concentrations followed by the viral challenge (Experiments 2 and 3). We also measured swimming performance in juvenile coastal cutthroat trout exposed to two 6PPDQ concentrations (Experiments 4 and 5).