Murphy, C.A., Cortes, A., Pollock, A.M.M., Gerth, W.J., Arismendi, I. and Konstantinidis P. 2025. First Documentation of Pelagic Larvae of Prickly Sculpin Cottus asper in Willamette Basin Reservoirs Using a Novel Light Trapping Method. Ichthyology and Herpetology. https://doi.org/10.1643/i2024026
Abstract
Depth discrete light traps effectively captured larval sculpin from Lookout Point Reservoir in the Willamette Basin, Oregon, USA. Here, we confirm that these larvae appear to be Prickly Sculpin (Cottus asper) based on morphology and genetics. We also document larval size and development, and examine monthly vertical distributions and sympatric invertebrate taxa. Pelagic larval sculpin were captured during early summer and exhibited a tendency towards deeper reservoir habitats with increases in average body sizes as the season progressed. We found most larval sculpin at locations within the main reservoir body, several kilometers downstream of riverine areas. Interestingly, the abundance of larval sculpin per trap was strongly associated with aquatic mites (absent from sculpin stomachs). These suggest potentially shared ecological drivers of the observed distributions of larval sculpin and mites. Collectively, we demonstrate that light trapping can be a useful method for collecting juvenile sculpin from reservoirs, with the potential to improve our understanding of distribution, life-history patterns, and ecology throughout their range.