Yahya related to me from Malik from Nafi that Abd ar-Rahman ibnAbi Hurayra asked Abdullah ibn Umar about eating what was cast up bythe sea and he forbade him to eat it. Then Abdullah turned and askedfor a Qur'an, and read, "The game of the sea and its flesh are halalfor you." Nafi added, "Abdullah ibn Umar sent me to Abdar-Rahman IbnAbi Hurayra to say that there was no harm in eating it."
USC-MSA web (English) reference: Book 25, Hadith 9
Arabic reference: Book 25, Hadith 1061