Italy and France represent Mediterranean countries where it has been possible to compare the requirements of the aquaculture sector opinion leader. The Mediterranean species raised in the two countries are similar, so it has been possible to compare the trend operating to diversify the species or to differentiate the product supply. In Italy, questionnaires have been distributed, whereas in France the results of a previous survey have been used. In both countries, the interviewees have mentioned the possibility to innovate the field, developing a marketing policy oriented to the differentiation of product supply, rather than introducing the new breeding species. The introduction of new seafood products represents a marketing choice, which is an answer to consumer demands. The choice to differentiate products, rather than to diversify the species, is guided by insufficient information on new economically interesting technologies and species which could be raised.