Effect of turbulence on the feeding and moulting of the cirripede Balanus Balanoides (L.) given an algal diet

The shell growth, moulting, and faecal pellet production of Balanus balanoides (L.) have been investigated experimentally in turbulent and quiet conditions. In turbulent conditions an algal food level of 50% was sufficient to maintain the same shell growth as at the 100% level, whereas at this level in quiet conditions growth was less than at 50% with turbulence. At the 10% food level growth was markedly reduced in quiet conditions. On the assumption that production of faeces is a measure of feeding activity, the latter is stimulated by turbulence as is the moulting rate. The relation between production of faeces and moulting is, however, independent of water movement. Faecal pellet production continues at higher algal food levels after the growth rate has become constant indicating that when assimilation is maximal there is no feed-back mechanism regulating food intake.