CTF-150 (Combined Task Force - 150) has been providing security for merchant shipping transiting the Gulf of Aden. However it was created to provide maritime security in support of Operation Enduring Freedom. Now CTF-151 has been created specifically to combat piracy.
From the site EagleSpeak - Combined Maritime Forces Counter-Pirate Force CTF-151.
"The CMF created the Maritime Security Patrol Area (MSPA) in the Gulf of Aden in August of 2008 to support international efforts to combat piracy. Coalition efforts included CTF-150 assets patrolling the area with ships and aircraft. However, the charter for CTF-150, established at the outset of Operation Enduring Freedom, was for the conduct of Maritime Security Operations (MSO) in the Gulf of Aden, the Gulf of Oman, the Arabian Sea, Red Sea and the Indian Ocean."K.C.