Sailor marooned finds snail (7)
I believe the answer is:
abalone
'snail' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'sailor marooned' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'marooned' becomes 'alone' (similar in meaning).
'ab'+'alone'='ABALONE'
'finds' is the link.
Can you help me to learn more?
(Other definitions for abalone that I've seen before include "Mollusc with an oval shell lined with bluish mother-of-pearl" , "Edible marine mollusc -- Oban ale (anag)" , "Ormer, ear shell" , "Seafood" , "Mollusc also called ormer" .)