This powerful technique enabled the visualisation of a total of 150 protein spots consistently expressed in the foot. The intensity of 92 selected spots was compared between intertidal and cultured mussels, and statistically significant differences were detected in the expression of 45 (48.9%) of the 92 proteins analysed. In 31 of these proteins intensity was higher in the cultured stock than in the intertidal mussels, while in 14 proteins spot intensity was higher in the latter