Hadith 1243
Abu Huraira (may Allah be pleased with him) narrates: A man asked the Prophet (peace be upon him), he said: O Messenger of Allah! We travel by sea and we take only a small amount of water with us. If we use it for ablution, we will remain thirsty. Can we perform ablution with sea water? The Prophet (peace be upon him) said: Its water is pure and its dead (animals) are lawful.