Working Groups are normally established either in a formal or informal manner in the context of the bodies (decision-making and subsidiary) of CMS and its instruments. Some of these Working Groups operate only during the meeting of these bodies while others have the mandate to work intersessionally to provide advice or recommendations. Depending on the nature of their mandate, Working Groups can be composed of Member States’ representatives or scientific experts within or without the technical bodies of these instruments.

A number of further Working Groups on various issues and species have been established under the Agreements and MOUs.