Catches in the river and the locals are put out about it (7)
I believe the answer is:
collars
'catches in the river' is the definition.
'collars' can be an answer for 'catches' ('collar' can be a synonym of 'catch'). I am not certain of the 'in the river' bit.
'the locals are put out about it' is the wordplay.
'are put out' is an anagram indicator.
'about' means one lot of letters goes inside another.
'it' becomes 'r' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'locals' anagrammed gives 'collas'.
'collas' placed around 'r' is 'COLLARS'.
'and' is the link.
Can you help me to learn more?
(Other definitions for collars that I've seen before include "Grasps" , "Ties with them, perhaps" .)