A recreational fisherman accused of a screwdriver stabbing murder on the shores of the Swan River argues he was acting in self-defence when the intoxicated stranger charged at him and accidentally impaled his head on the tool.

Andrew Doan had been fishing with a friend in East Fremantle in the early hours of December 23, 2017, when he became embroiled in an argument with Charles John McCarthy, who had been out drinking at a Christmas party with his wife and a male friend.

Defence counsel Michael Perrella told the WA Supreme Court on Monday his client, who is Asian, became angered after Mr McCarthy's friend made a racist comment.

A verbal argument and scuffle ensued, and Mr Doan was holding his arms up to protect his face — screwdriver in hand — when an enraged Mr McCarthy charged, impaling himself in a "freak and tragic accident", Mr Perrella said.

AAP