STEEVES, T.E.; BOURNE, G.B.*; Univ. of Calgary and Bamfield Marine Sciences Centre; Univ. of Calgary and Bamfield Marine Sciences Centre: Feeding behavior and the distribution of the muricid gastropod Ceratostoma foliatum in Barkley Sound, British Columbia

We examined feeding behavior, prey preferences, and predator and prey densities of three populations of Ceratostoma foliatum (Gmelin, 1791) in Barkley Sound, British Columbia. Although the primary prey available to each population was different [Dodecaceria fewkesi at Ellis Island (EI), Balanus crenata at Fleming Island (FI) and Balanus glandula at Kirby Point (KP)], we found no significant difference in the density of Ceratostoma among the three locations. At the EI and FI sites, we found that the density of Ceratostoma tended to increase non-significantly with density increases of the primary prey. However, at the KP site there was a negative correlation between densities of Ceratostoma and B. glandula. In the laboratory, we performed a series of prey choice experiments involving D. fewkesi, B. glandula, Mytilus spp. and Protothaca staminea. Ceratostoma from all three populations preferred B. glandula almost exclusively. When preying upon B. glandula, these gastropods used the accessory boring organ and radula to drill the opercular plates, but they may have crushed the plates using the labial spine. While feeding on D. fewkesi, Ceratostoma either drilled into the calcareous tubes or directly everted their proboscises into tubes.