Blue mussels (Mytilus edulis) and soft-shell clams (Mya
arenaria) are both aquaculture species in east coast of Canada and US shellfish
farmers take advantage of the byssal threads production of mussels for suspension culture
and the burrowing behaviour of soft-shell clams for enhancement practices. It is important
that these animals attach and burrow efficiently to minimize losses during rearing. The
aim of this work was to study two potential vitality indices on mussels (23.6 ± 0.1 mm) and clams (22.6 ± 0.1 mm) seeds following various
periods of emersion: attachment strength of Mytilus edulis and burrowing
ability of Mya arenaria. The effect of emersion on energy content
(proteins, lipids, glycogen) was also examined. We observed no significant decrease in the
attachment strength of mussels after air exposure for 78 h or in the burrowing efficiency
of soft-shell clams after 54 h. Air exposure had no effect on different lipid classes,
proteins, or glycogen content in either mussel or clam tissues. The stressful emersion
event induced in our study may not have been high enough to induce detectable behavioural
responses. This can be explained by the bivalves’ ability to adapt their metabolism to
minimize activity during air exposure. In doing so, they do not consume their energy
reserves, which are then still available when specimens are reimmersed. Thus mussels are
able to efficiently produce byssal threads and clams to burrow into sediments as soon as
they are back in the water.