This work focus on the process of technological change in the economic activity of a colony of fishermen in Guanabara Bay. The difficulties and the dilemmas they faced during the absorption of a innovative conduct from technical point of view which checkmated their traditional forms of production have been little studied in the literature. The technological change involved the adoption of new environmental management codes and new technical procedure which resulted in the transformation from a traditional form of production to a semi-industrial one. On the one hand, such regulations as the control of adequate environmental conditions to guarantee product quality were well accepted, and assimilated by the social group. On the other hand, resistance to the new technical proposal, new institutional arrangements, and to collective learning, hampered to a certain extent the transition process, bringing to light the dilemmas the social group had to overcome to absorb completely the process of technological change.