Swede, perhaps, nets top salmon and perch (5)
I believe the answer is:
roost
'perch' is the definition.
('roost' can be a synonym of 'perch')
'swede perhaps nets top salmon' is the wordplay.
'swede perhaps' becomes 'root'.
'nets' means one lot of letters goes inside another.
'top' indicates taking the first letters.
The initial letter of 'salmon' is 's'.
'root' going around 's' is 'ROOST'.
'and' acts as a link.
(Other definitions for roost that I've seen before include "unwelcome to come home to?" , "Place where birds rest" , "Torso (anag)" , "In Orkney, the current" , "Resting perch for birds" .)