Oceanic zones that mount freedoms (5,9)

I believe the answer is:

horse latitudes

I'm a little stuck... Click here to teach me more about this clue!

'oceanic zones' is the definition.
The answer and definition can be both locations as well as being plural nouns.
Maybe there's an association between them I don't understand?

'mount freedoms' is the wordplay.
'mount' becomes 'horse' (I've seen this before).
'freedoms' becomes 'latitudes' (latitude is a kind of freedom).
'horse'+'latitudes'='HORSE LATITUDES'

'that' is the link.

Can you help me to learn more?

(Another definition for horse latitudes that I've seen is " Atlantic zones".)

I've seen this clue in the Sydney Morning Herald.

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