Seafood, and a sort of apple (4)
I believe the answer is:
crab
I believe this clue is a double definition.
'seafood' is the first definition.
(crab is a kind of seafood)
'a sort of apple' is the second definition.
'and' is the link.
(Other definitions for crab that I've seen before include "Clawed shellfish" , "A crustacean; type of apple" , "Sideways scuttler" , "One may be caught" , "Scuttling crustacean" .)