Throw nearly all back that's caught in the sea (7)
I believe the answer is:
lobster
'caught in the sea' is the definition.
I can't tell whether this definition defines the answer.
'throw nearly all back' is the wordplay.
'throw' becomes 'lob' (lobbing is a kind of throwing**).
'nearly all' means to remove the last letter.
'back' becomes 'stern' (I've seen this before).
'stern' with its final letter taken away is 'ster'.
'lob'+'ster'='LOBSTER'
'that's' is the link.
Can you help me to learn more?
(Other definitions for lobster that I've seen before include "food?" , "One showing claws" , "Bolster up the sea-creature" , "Slow bowler may be" , "Pincered crustacean, a delicacy" .)