Shark Baiter Meaning

(Australia, colloquial) A lone swimmer or surfer far from shore; shark bait.

Example: Used other than as an idiom: see shark,‎ baiter.
1912, Arthur Wright, Rung In, pages 34-5, quoted in G. A. Wilkes, A Dictionary of Australian Colloquialisms,
  It might be only some foolhardy ‘shark baiter’ as he heard the more adventuresome of the bathers called.
1964, Council for Scientific and Industrial Research (Australia) Division of Fisheries, et al., Fisheries Newsletter, Volume 23, page 26,
  Solitary bathers are more often attacked than groups, Mr. Whitley says, but the “shark-baiter” farthest offshore is not necessarily the one selected.