Sea food from Yes Tor possibly (6)
I believe the answer is:
oyster
'sea food' is the definition.
(oyster is a kind of sea food)
'yes tor possibly' is the wordplay.
'possibly' is an anagram indicator.
'yes'+'tor'='yestor'
'yestor' with letters rearranged gives 'OYSTER'.
'from' is the link.
(Other definitions for oyster that I've seen before include "Pearl-bearing sea creature" , "Bivalve that may nurture a pearl" , "rather grey" , "Edible shellfish" , "Food shellfish" .)