Green’s Dictionary of Slang

(Aus.) a shrimp-like crustacean (Baker, 1941 says ‘prawn’ but cites differentiate).

1895		Illawarra Mercury (Wollongong, NSW) 22 Oct. 2/5: The fishing is very lively during the autumn months. Prawns, pippies and nippers will be found the best bait.
1901		Sydney Mail 14 Sept. 698/1: As crayfish, miscalled lobsters, are plentiful, they can be used for bait in preference to prawns, nippers, or fish bait.
1917		Referee (Sydney) 18 July 11/7: Nippers may be obtained by tramping on the mud.
1924		Newcastle Morn. Herald 26 July 10/5: Worms, prawns and nippers are the favourite bait. although some anglers prefer the soldier, and black crabs.
1931		Arrow (Sydney) 2 Oct. 16/1: Where To Fish. WOY WOY: Whiting on live nippers and worms from moored boats and on prawns and worms drifting along edges of flats.
1941		Baker Popular Dict. Aus. Sl.
1946		Sun (Sydney) 28 July 25/2: Black bream are plentiful in George's River and in the Hawkesbury. George’s River [...] anglers are doing best with nippers as bait, but prawns are a good substitute.
1951		Cessnock Eagle (NSW) 20 July 2/3: The following bait is equally good to tempt the bream: Live worms, live sand nippers, green nippers, live prawns, the red flesh at the tail of a salmon.
1967		Canberra Times (ACT) 20 Oct. 20/7: Beach worms, nippers, prawns, shell fish and concoctions such as cheese and pudding are recognised baits [for bream].