The use of non-entangling and biodegradable components-based FADs (i.e., BIOFAD) by the tropical tuna purse seine industry is promoted by tuna Regional Fisheries Management Organizations through different recommendations and resolutions published during the last years. This implies the development of an accurate definition of what a BIOFAD should be, and specially the conditions to be met by the materials used in their construction when applying biodegradability requirements for permitted materials. This document tries to address specific conditions to be considered when the word biodegradable is applied to define the materials used for BIOFAD construction.