Graduate on ship sees fish (4)
I believe the answer is:
bass
'fish' is the definition.
(I've seen this before)
'graduate on ship' is the wordplay.
'graduate' becomes 'ba' (**).
'on' means one lot of letters go next to another.
'ship' becomes 'ss'.
'ba'+'ss'='BASS'
'sees' acts as a link.
(Other definitions for bass that I've seen before include "Fish (which sings?)" , "Lowest male singer" , "Very low - perch" , "Fish; male singing voice" , "Scottish rock" .)