There have been at least fifty attacks since January in the Gulf of Aden and Indian Ocean. The International Maritime Bureau, a private non-profit organisation that tracks such data, says seizures of ships and sailors are running at their highest level since 1991, when it first started to collect piracy data.
If the EU does decide to act, their justification is within the framework of United Nations Security Council resolution 1816, which the members unanimously adopted in June. The potential action is also in line with their recent higher-profile role in efforts to promote security in Africa, having deployed a 3,700-strong peacekeeping force in eastern Chad this year.
The next more positive development, although there are no signs of anything of the sort happening now, is that India and possibly China would send additional personnel.