Skate bait is a derogatory term heard in sea-faring towns around
England - it is slang for the type of
girl who hangs around near the
port waiting for sailors (or skates). Where I grew up, in
Portsmouth, skate bait were considered to be
tarts who only went out with
sailors because they had plenty of money. While not
prostitutes, sexual favours would be readily given in return for a good night out, which presumably kept everyone happy! Another, even more insulting name for this type of woman is
Matelot's mattress.
Alternatively, skate bait is literally that - skate used as bait. Skate is a type of fish which is often discarded when caught because it is not deemed to be as tasty as flounder, cod, haddock and the like. There is a market for skate wings in Europe, but that is the only part of the fish which is eaten. The rest is either thrown back into the sea, or used as bait in the lobster industry. The increase in demand for skate bait has actually led to overfishing for skate in recent years and subsequent depletion of stocks in the wild.
http://www.nefsc.nmfs.gov/sos/spsyn/op/skate/