Fishing activities are not generally regulated in order to protect and preserve the marine ecosystem, but rather to conserve stocks for future exploitation. This may have to change, as evidence shows that fishing activities are having serious negative effects on the marine ecosystem. The subject is on the agenda of the Ministerial Conferences for the Protection of the North Sea and will be considered at a ministerial working group in 1993. The article focuses on the regime available for regulating fishing activities so as to ensure the protection and preservation of the marine ecosystem. The author concludes that, although the obligation to ensure the protection of the environment also applies to fishing activities, international instruments are not tailored to deal with this issue. Within the European Community the required integration of environmental considerations into other policies, however, provides an opportunity for tackling the matter. The author suggests that a precautionary approach be adopted in regulating fishing activities. This would not require the adoption of new legal instruments, such as an exclusive economic zone (EEZ), but rather the adoption of a new philosophy in the implementation of existing instruments.