Q 9: From where is derived the ruling on the prohibition of
eating the meat of marine creatures that feed on decayed carcasses
The basic ruling is that all sea creatures are Halal (lawful) to eat, according to the general meaning of Allah’s Saying:
Lawful to you is (the pursuit of) water-game and its use for food - for the benefit of yourselves and those who travel, but forbidden is (the pursuit of) land-game as long as you are in a state of Ihrâm (for Hajj or ‘Umrah).
This is so, unless anything is confirmed that changes this permissibility. Supporting evidence for this is the saying of the Prophet (peace be upon him) about the sea,
“Its water is a purifier and its Maytah (dead sea creatures) are Halal.”