The Halifax tanker, which was hijacked by pirates on October 30, 2011, with one Bulgarian crew member, has been released.

Halifax, which sails under Maltese flag but is managed by the Greek-based company Ankora Investment Trust, was freed late Saturday, the Nigerian maritime administration announced, as cited by international media.

The tanker ship crew consists of 24 Filipinos and one Bulgarian; the Nigerian authorities say the vessel has been escorted by a sea patrol to Port Harcourt.

Unlike their "colleagues" from the coast of Somalia and the Gulf of Aden, the pirates in the Gulf of Guinea stretching from Guinea to Angola on the West African coast hijack ships to steal cash and goods rather than to get ransom, experts say.

Even though the hijackings in the Gulf of Guinea are not as many as in the Gulf of Aden, their number is on the rise, which threatens to jeopardize the potential of the West African coast as an emerging commercial center.