Opponents of the West Australian government's shark culling program have responded angrily to the first killing in the state's waters.

A fisherman contracted by the WA government to set and monitor baited drum lines one kilometre off beaches in the South West region was reportedly seen on Sunday morning shooting a large shark off Meelup beach, near Dunsborough, about 250 kilometres south of Perth.

Controversial plan: WA Premier Colin Barnett. Credit:Bohdan Warchomij

The shark had been caught in the drum lines, which were set up on Saturday, and was then towed further out to sea.