Laboratory food choice by the mosshead sculpin, Clinocottus globiceps (Girard) (Teleostei; Cottidae), a predator of sea anemones

Mosshead sculpins, Clinocottus globiceps (Girard), are unique among rocky intertidal fishes of the North American Pacific coast in preying heavily upon sea anemones. We examined food choice by C. globiceps for various food types offered simultaneously in laboratory trials. Both large and small C. globiceps attacked anemones ( Anthopleura elegantissima (Brandt) and Epiactis prolifera (Verrill)) more frequently than shrimp or algae, and small C. globiceps showed some tendency to attack anemones earlier in the trials than they did other food types. Comparing the responses of C. globiceps only to sea anemones in these multi-food trials, small C. globiceps attacked Epiactis significantly more frequently and generally sooner than they did A. elegantissima, but such preference for Epiactis over A. elegantissima was less evident in large fish. In additional trials where C. globiceps were offered paired anemone species but no other food types, the fish did not show statistically significant preferences in terms of numbers of bites or order of attacks on either of the two anemone species within each pair. However, using the number of bites taken of A. xanthogrammica as a standard for reference, there were relatively more bites of Epiactis and fewer bites of A. elegantissima in these paired-species trials, thus suggesting a preference for Epiactis over A. elegantissima. The anemone-eating habit perhaps accounts at least in part for several features of C. globiceps — including a relatively large body size, blunt head shape, and a seemingly low reliance on a spin-feeding mode — that together make this species one of the most distinctive of the intertidal sculpins.