FOOD PREFERENCES AND FEEDING RATES OF SLIMY SCULPIN

Darcy Mundahl1 and Neal Mundahl2

1Winona Senior High School, Winona, MN 55987

2Winona State University, Winona, MN 55987

      Slimy sculpin (Cottus cognatus) diet preferences and food consumption 
rates were examined in a series of field and laboratory experiments.  Food 
consumption rates of sculpin were tested in 24-h feeding experiments conducted 
at three different temperatures (12°C, 17°C, and 22°C), with amphipods as prey.  
Natural diets were assessed by examining stomach contents of sculpin collected 
from six streams in southeastern Minnesota.  Benthic samples also were collected 
from the same streams to assess the availability of sculpin prey.  In the 24-h 
feeding experiments, sculpin consumed marginally more amphipods per fish body 
weight at 17°C than either of the other temperatures (12°, 27.3 mg food/g fish; 
17°, 46.6 mg food/g fish; 22°, 29.8 mg food/g fish).  In the field diet 
analysis, sculpin consumed 33 different types of prey, but showed strong 
preferences (Ivlev’s electivity index) toward fly larvae and amphipods.  Benthic 
samples indicated that preferred prey items were abundant in most streams.  
Slimy sculpin have broad diets, but prefer and consume mostly fly larvae and 
amphipods.  Sculpin consumed more food at 17°C, a typical summertime water 
temperature for coldwater streams in southeastern Minnesota.

Key words: slimy sculpin, invertebrates, food preferences, feeding rate, 
temperature