The omnipresence of science in environmental protection has led law-makers to consult experts. In terms of management and conservation of fisheries, this interaction between science and law has been institutionalized within Regional Fishing Commissions through the creation of permanent scientific committees. These committees are made up of experts and give advice to Commissions, who use it to set up the rules which regulate management decisions. Although at first sight the scopes of respective roles seem strictly defined, one can note, particularly through the case of the International Commission for the Conservation of Atlantic Tuna, that more than an interaction we are may be witnessing a mix-up between science and law.