Published online by Cambridge University Press: 04 April 2001
In situ seasonal study of siphonal activity in Mya arenaria (ten individuals) was performed using a fixed video camera during nine complete submersion cycles between May and November 1996. Siphonal activity was described by exhalant and inhalant siphon simultaneous closure frequencies (EIC), pseudofaeces production frequencies (PFC) and both siphons opening state duration (OPE). A repeated measure ANOVA model showed a slight OPE increase between May and June and a strong OPE and EIC decrease from October. A non-linear probit model on the proportion of individuals showing PFC events during submersion cycles indicated a progressive decrease of this behaviour with time. The siphonal activity was relatively high until September and then decreased from October suggesting a marked reduction of the feeding activity.