As an outermost region (OR) of the European Union, Reunion Island is subject to the common fisheries policy (CFP) which aims to promote sustainable and economically viable fishing and aquaculture activities, in particular by encouraging the transformation products resulting from their activities. The control of the sectors by the follow-up of the traceability and the financial support makes it possible to meet its objectives. Conversion coefficients for each processing and for each species or group of species of fish marketed are used in the tools for monitoring fisheries (fishing declaration and purchasing obligations) and in the calculation of the amount of aid allocated to the sectors by the European Maritime, Fisheries and Aquaculture Fund (FEAMPA). The scale of coefficients currently applied in Reunion is inconsistent and does not comply with the CFP control regulations. A consolidated list of conversion factors for the different fish processing is proposed here for application in the Reunion region.