Habitat separation of prickly sculpin, Cottus asper, and coastrange sculpin, Cottus aleuticus, in the mainstem Smith River, northwestern California

Sympatric coastrange sculpin, Comes aleuticus and prickly sculpin, C. asper , occupied distinct habitats in the mainstem smith River, northwestern Cali fornia. For example, 90% of coastrange sculpin (n = 294) used habitat with water velocity > 5 cm . s(-1), whereas 89% of prickly sculpin (n = 981) use d habitat with water velocity less than or equal to 5 cm . s(-1). Sixty-fiv e percent of coastrange sculpin were found at depths < 1 m, whereas 37% of prickly sculpin occupied depths > 7 m. The strong spatial separation of coa strange and prickly sculpin in the mainstem Smith River contrasts with the overlap in their nse of habitat in the nearby Eel River. Differences betwee n the rivers in habitat availability, intensity of piscivory, and density o f sculpins may con tribute to this contrast.