Since 1993, the prime goal of Dutch fisheries policy has been to enhance a responsible way of fishing and a sustainable exploitation of fish stocks. That is, economic and ecological interests should be balanced in a viable way so as to achieve both economic and ecological sustainability. This policy, which encouraged new forms of cooperation, was superimposed on a system of individual transferable quotas that was officially introduced in 1985. To arrive at devolution of specific management responsibilities to fishermen, they had to organise themselves in co-management groups, the so-called 'Biesheuvel groups'. Individual fishermen bring their catching rights or quotas into these groups, and these groups are responsible for establishing fishing plans to achieve a better distribution of sea days and quota transfers within a group. The state's aim is to enhance fishermen's responsibility and social control through self-management. This chapter will address the experiences over the past ten years with this governance system, focussing especially on the conflicting views of fishermen, biologists and state representatives regarding its efficacy. Special attention will also be devoted to the perceptions of the beam trawl fishermen concerning the benefits and pitfalls of the present governance system.