Problem with area housing the Spanish source of caviar (6)
I believe the answer is:
beluga
'source of caviar' is the definition.
(I've seen this in another clue)
'problem with area housing the spanish' is the wordplay.
'problem with' becomes 'bug' (I can't justify this - if you can you should give a lot more credence to this answer).
'area' becomes 'a' (maths abbreviation).
'housing' means one lot of letters goes inside another.
'the spanish' becomes 'el' ('the' in Spanish).
'bug'+'a'='buga'
'buga' going around 'el' is 'BELUGA'.
Can you help me to learn more?
(Other definitions for beluga that I've seen before include "Large Russian sturgeon" , "Small white whale; type of caviar" , "Small northern white whale" , "Could a bugle be a source of caviar?" , "large marine creature" .)