A miner in the sea (6)

I believe the answer is:

marine

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

'in the sea' is the definition.

'a miner' is the wordplay.
'a miner' can be anagrammed to 'MARINE'.
However, I am not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for marine that I've seen before include "Relating to shipping or naval matters" , "Relating to the sea" , "jolly" , "Airmen (anag.)" , "Oceanic" .)

I've seen this clue in The Irish Independent.

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