Yellowfin bites deerskin in Arctic ecosystem (6)
I believe the answer is:
tundra
'arctic ecosystem' is the definition.
(I've seen this in another clue)
'yellowfin bites deerskin' is the wordplay.
'yellowfin' becomes 'tuna' (I've seen this in another clue).
'bites' indicates putting letters inside.
'deerskin' becomes 'dr' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tuna' placed around 'dr' is 'TUNDRA'.
'in' is the link.
Can you help me to learn more?
(Other definitions for tundra that I've seen before include "Vast Artic region with frozen sub-soil" , "Cold northern region" , "Treeless Arctic region" , "Vast level Arctic region with frozen subsoil" , "Vast treeless plane" .)