Somali pirates released the Singapore-flagged cargo vessel MT Gemini after receiving a ransom, but are continuing to hold four South Korean crew members, a Kenyan piracy expert was quoted as saying Thursday. Despite the ransom which has been paid, yet the ship is still there, and the four Korean crew members were taken ashorebut nobody knows how much,'' Andrew Mwangura, regional piracy expert and maritime editor of Somalia Report said. Mwangura said that the vessel, which was seized on April 30 with a crew of 25 from South Korea, Indonesia, Myanmar and China, was expected to set sail shortly. The release of the vessel drops to nine the number of ships being held by the pirates who have plagued shipping lanes in the Gulf of Aden and Indian Ocean, according to statistics released by the European Union''s anti-piracy mission EU NAVFOR. The number of vessels held has been dramatically reduced this year, as the pirates struggle to take new vessels in face of on-board security teams and better security practices by shipping firms.