Pilchard's kin (5)
I believe the answer is:
sprat
'pilchard's kin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sprat that I've seen before include "'Set a . . . . . to catch a whale'" , "'Set a . . . . . to catch a herring'" , "Jack, perhaps" , "Traps (anag.)" , "Tiny fish" .)