Marine creature bringing credit to a seaman (4)

I believe the answer is:

crab

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'marine creature' is the definition.
'crab' can be an answer for 'creature' (crab is a kind of creature). I'm not sure about the 'marine' bit.

'credit to a seaman' is the wordplay.
'credit' becomes 'cr'.
'to a seaman' becomes 'ab'.
'cr'+'ab'='CRAB'

'bringing' acts as a link.

Can you help me to learn more?

(Other definitions for crab that I've seen before include "One may be caught" , "A crustacean; type of apple" , "one is a fiddler" , "terrible row" , "Shellfish with pincers" .)

I've seen this clue in the Evening Standard.

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