Marine animals, say, included marine adjustment (7)

'included marine adjustment' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'marine animals say' is the wordplay.
I cannot quite see how this works, but
'marine' could be 'sea' (both can mean 'of the sea') and 'sea' is found within the answer.
'say' could be 'eg' (both can mean for example) and 'eg' is found within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?