92 Fred C. Rohde and Rudolf G. Arndt 



Table 8. Mean number of food items, by length groups, in stomachs of Cottus 

 bairdi from Butler Mill Branch, Sussex County, Delaware, 1973-1980. 



Food 



Cottus SL (mm) 

 <20 20-29 30-39 40-49 >49 





.01 



.04 





.01 



.01 



.15 



.04 



.16 



.01 







.01 



.36 



.53 





.03 



.04 



.13 



.15 



.06 



.04 



.10 



.06 



.02 



.02 





.02 



.02 



.01 



Nematoda 



Oligochaeta 



Crustacea 



Amphipoda .22 .15 .04 .16 .08 



Isopoda 

 Insecta 

 Plecoptera 



Perlodidae 



Chloroperlidae 



Unidentified 

 Ephemeroptera 



Heptageniidae .06 .04 .06 



Leptophlebiidae 



Unidentified 

 Odonata 



Anisoptera .01 



Zygoptera .01 



Trichoptera 



Hydropsychidae 1.17 



Phryganeidae 



Unidentified 

 Coleoptera 



Elmidae 



Gyrinidae 



Unidentified 

 Diptera 



Chironomidae 7.89 



Simuliidae 



Tipulidae 



Unidentified .01 



Osteichthyes 



Lampetra aepyptera .08 



Etheostoma olmstedi .0 1 



Number of stomachs with 

 countable food items 18 122 152 68 13 



Abundance 



Throughout most of this study we assumed that the Butler Mill 

 Branch sculpin population was small. Work in early 1980, however, 

 revealed the species to be more widely distributed here than previously 



.89 



.94 



1.16 



1.23 



.01 









.09 



.19 



.04 





.01 



.06 



.01 





.01 



.01 







1.61 



2.51 



.28 



.23 



.10 



.05 

 .03 



.19 



.46 



