Swirling sea mist depicted by French painter (7)
I believe the answer is:
matisse
'french painter' is the definition.
(I've seen this before)
'swirling sea mist' is the wordplay.
'swirling' is an anagram indicator.
'sea'+'mist'='seamist'
'seamist' with letters rearranged gives 'MATISSE'.
'depicted by' is the link.
(Other definitions for matisse that I've seen before include "Henri --, French artist" , "Is mates turned on the French painter" , "Leading fauvist painter, d. 1954" , "Henri -, Fr. artist" , "20th century French painter" .)