Surface not popular for marine creature (4)
I believe the answer is:
fish
'marine creature' is the definition.
'surface not popular' is the wordplay.
'surface' becomes 'finish' (finishing is a kind of surfacing).
'not' suggests deleting specific letters.
'popular' becomes 'in'.
'finish' with 'in' taken out is 'FISH'.
'for' is the link.
(Other definitions for fish that I've seen before include "Customer" , "Aquatic animal(s)" , "Trawler's catch" , "Aquatic creature; rail-joining plate" , "joint strengthener" .)