Difficulty for fishermen? (5)
I believe the answer is:
catch
'difficulty' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for catch that I've seen before include "Trap - hear - contract" , "Hear < hit" , "Grasp - overtake - overhear - surprise" , "secure" , "Ensnare" .)