A Sydney man who herded a great white shark into shallow waters with his boat before it was bludgeoned on the head with a metal pole has been ordered to pay almost $20,000.

Just days after thousands of people gathered across Australia, New Zealand and South Africa to protest against Western Australia's shark cull, Justin Adam Clark, 40, of Glenbrook, was found guilty of harming a threatened species.

Catch leads to court: The juvenile great white shark was slashed by the boat propeller and later bludgeoned.

Clark used his boat to hit the juvenile shark a number of times, slashing it with the propeller, at Sussex Inlet near Jervis Bay in January 2012.

A second vessel towed the shark to a boat ramp before it was bashed on the head several times with a metal pole, Wollongong Local Court was told.