Iranian Vessel Released by Pirates

http://www.eunavfor.eu/2010/03/iranian-dhow-released-by-pirates/

An Italian frigate attatched to a NATO anti-piracy force had been monitoring an Iranian vessel believed to be hijacked some 5 months previously. On Wednesday the NATO ship observed Somali pirates leaving the hijacked vessel in small boats called skiffs. The next morning the frigate responded to a call for assistance, boarding the Iranian ship and distributing supplies to the 19 crew members. Some minor repairs were also conducted. It is believed that the pirates abandoned the vessel in response to more aggressive patrols from EU and NATO forces. The captured vessel was of the type that could have been used by the pirates as a "mothership" for launching smaller boarding ships.

Do you think the level of EU and NATO cooperation in this region is strong? Why is it necessary that both be present when they are both largely comprised of the same member states?