The incident happened in the 29th over and Jadeja was found to have breached Article 2.1.4 of the ICC Code of Conduct which relates to 'using language or a gesture that is obscene, offensive or insulting during an International Match'.
After the end of the play, Jadeja admitted the offence and accepted the sanction proposed by Match Referee Andy Pycroft.
"Mr Jadeja's reaction after dismissing Shane Watson was clearly in breach of the Code as the players are always expected to respect their opponents, no matter what the match situation. Mr Jadeja apologised for his action when on-field umpire Nigel Llong spoke to him immediately after the incident and reminded him of his responsibilities," Pycroft said in an ICC release.