Offiziere.ch has an excellent post on the problems of managing fisheries off Africa. While they talk about illegal, unreported and unregulated (IUU) fishing, that is only the beginning.

Among other problems, there are so many countries in Africa (54 countries, at least 32 with coast lines) that their individual EEZs are too small to manage fishing stocks. If one country attempts to rebuild stocks by reducing fishing, a neighboring country may take advantage of their sacrifice and undo their efforts.