Damage in French port reduced such seafood (8)
I believe the answer is:
calamari
'seafood' is the definition.
(calamari is a kind of seafood)
'damage in french port reduced' is the wordplay.
'damage' becomes 'mar' (marring is a kind of damaging).
'in' is an insertion indicator.
'french port' becomes 'calais' (I've seen this before).
'reduced' means to remove the last letter.
'calais' with its last letter taken off is 'calai'.
'mar' going inside 'calai' is 'CALAMARI'.
'such' is the link.
(Other definitions for calamari that I've seen before include "Squid served as food" , "seafood" , "Dish of squid" , "Squid prepared as food" , "Mollusc" .)