It is possible that starfish could aid in the cleaning of mussels by
preying on the barnacles fouling the shells. Barnacles have been noted
as a preferred food of smaller A. rubens with the ability to consume up
to 200 barnacles per week (Hancock, 1955). We found that starfish of
all sizes consumed barnacles but not at a rate described by Hancock
(1955) and, thus, not at a rate that was likely to significantly reduce
fouling. Medium sized starfish feeding on large mussels were most
likely to consume barnacles from mussel shells. This may have been as
a result of a reduced feeding rate on fouled mussels of this size with
barnacles being easier to consume compared to eating whole fouled
mussels. Large starfish presented with small fouled mussels were less
likely to consume barnacles. This may also be because of handling
difficulties with the smaller mussels being harder to manipulate by
large starfish making it more problematic to consume the barnacles
fouling the shells.