Diet composition, feeding periodicity, and prey selection of slimy sculpin during winter

Abstract

Slimy Sculpin Cottus cognatus is an important component of the benthic ichthyofauna of many lakes and streams in the northern latitudes of North America. Although considerable information exists on the feeding ecology of this species, there is essentially no information available on winter feeding. Consequently, we examined the winter feeding ecology of Slimy Sculpins in a central New York stream. Ephemeropterans (37.8%) and trichopterans (31.2%) were the primary prey taxa consumed in January. There was evidence of diel variation in diet composition, with ephemeropterans making up 24.1% of the diet at 0400 hours and 46.7% at 1600 hours and trichopterans contributing 22.7% at 1200 hours and 43.8% at 2000 hours. During winter, Slimy Sculpins selected chironomids (0.46) and trichopterans (0.43) and avoided coleopterans (-0.84) and nonchironomid dipterans (-0.67). Peak food consumption of Slimy Sculpins occurred at night. Winter feeding patterns of Slimy Sculpins in Grout Brook, a second-order tributary of Skaneateles Lake in central New York, contrasted sharply with observations from other studies carried out during other seasons. Our findings are a significant contribution on the winter feeding ecology of this important benthic species and illustrate the need for both diel and winter studies to fully understand life history characteristics.