Land fish — one is thrown back, having been caught (7)
I believe the answer is:
tunisia
'land' is the definition.
(I know that Tunisia is a African country)
'fish one is thrown back having been caught' is the wordplay.
'fish' becomes 'tuna' (tuna is a type of fish).
'one' becomes 'i' (Roman numeral).
'is thrown back' becomes 'si' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'having been caught' indicates putting letters inside.
'i'+'si'='isi'
'tuna' going around 'isi' is 'TUNISIA'.
Can you help me to learn more?
(Other definitions for tunisia that I've seen before include "Country in North Africa" , "Republic in northwestern Africa" , "N African country in which ancient Carthage lies" , "African state" , "As Inuit visits there in North Africa" .)