Shock, finding purser is at sea (8)
I believe the answer is:
surprise
'shock' is the definition.
(I've seen this before)
'purser is at sea' is the wordplay.
'at sea' indicates an anagram.
'purser'+'is'='purseris'
'purseris' anagrammed gives 'SURPRISE'.
'finding' is the link.
(Other definitions for surprise that I've seen before include "Unexpected thing" , "Shock" , "Something unexpected" , "Astound" , "Startle, astonish" .)