Sea creature in western sound (5)
I believe the answer is:
whale
'sea creature' is the definition.
(creature of the sea)
'western sound' is the wordplay.
'western' becomes 'w'.
'sound' becomes 'hale' (both can mean healthy).
'w'+'hale'='WHALE'
'in' acts as a link.
(Other definitions for whale that I've seen before include "Moby-Dick" , "Large marine mammal" , "Maybe humpback" , "World's largest mammal" , "having such a good time?" .)