Prey attack, food preference and growth in juveniles of the edible muricidsnail, Chorus giganteus

Chorus giganteus is a marine snail with potential in aquaculture or sea-far ming. Considering predictions of optimal foraging, the aim of this study wa s to identify the preferred prey and to determine the extent to which this preferred prey promotes a higher rate of growth. Prey handling mechanisms, prey preference and resulting growth were assessed by offering C. giganteus the mussels Semimytilus algosus and Perumytilus purpuratus as alternative prey items. Juvenile snails of two size classes were used to assess handlin g behaviour and prey preference. Experimental treatments included mixed (S. algosus-P. purpuratus) as well as pure diets. A tendency to drill the prey shell, instead of using pedal handling, was observed in smaller snails (6- 8 mm), while among larger snails (10-12 mm), the handling mechanism depende d upon the prey species offered. Shell drilling was used more frequently to feed on P. purpuratus; in contrast, pedal handling was clearly favored whe n feeding on S. algosus. S. algosus was significantly preferred as prey (Qu ade test, T = 30.51; K1 = 1 and K2 = 8; P < 0.01), and the growth thus obta ined was significantly higher than with P. purpuratus as prey. (C) 1999 Els evier Science B.V. All rights reserved.