Dolphin habitats (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dolphin habitats</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for seas that I've seen before include "Oceans" , "Red and Black are" , "Bodies of salt water" , "Aegean and Mediterranean, say" , "Red and Dead" .)