Start to haul off fish (7)
I believe the answer is:
herring
'fish' is the definition.
(I know that herring is a type of fish)
'start to haul off' is the wordplay.
'start to' says to take the initial letters.
'off' becomes 'erring' (erring can mean inaccurate or off).
The initial letter of 'haul' is 'h'.
'h'+'erring'='HERRING'
(Other definitions for herring that I've seen before include "Common food fish" , "Fish of northern waters, can be salted or pickled" , "Saltwater fish" , "Important food fish" , "one could be soused" .)