How one might cook sea fish (4-3)

I believe the answer is:

deep-fry

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'how one might cook' is the definition.
'deep fry' can be an answer for 'cook' (I've seen this before). I'm not sure about the 'how one might' bit.

'sea fish' is the wordplay.
'sea' becomes 'deep' (I can't justify this - if you can you should give a lot more credence to this answer).
'fish' becomes 'fry' (I've seen this before).
'deep'+'fry'='DEEP-FRY'

Can you help me to learn more?

(Other definitions for deep-fry that I've seen before include "Cook (chips etc)" , "Fed pyre (anag.)" , "Cook in oil" .)

I've seen this clue in The Telegraph.

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