Fish oil producer Zapata has rejected an unsolicited US$45 per share cash offer to acquire the company. Zapata's board said that accepting the offer from Hollingsworth, Rothwell & Roxford would not be in the best interest of Zapata or its shareholders. Zapata, which was founded as an oil and gas company by former US president George Bush nearly 50 years ago, owns Omega Protein, the US' largest producer of fish meal and fish oil.