Shahriar was found guilty of dissent by match referee Jeff Crowe in a hearing after play in which he had been dismissed lbw for a duck on the third ball of the innings to Aussie left-armer Mitchell Johnson.
An ICC statement said the player admitted to a breach of 1.3 of the ICC Code, which relates to "showing dissent at an umpire's decision by action or verbal abuse."
"The offence related to his reaction when he was given out leg before wicket to the third ball of the match. Shahriar shook his head and gestured with his bat towards the Bangladesh dressing room as he left the field," said the statement.
In explaining his decision, Crowe said: "The player admitted what he had done was wrong and I took this, together with his previously exemplary conduct, into account.
"However, it is important to show that dissent of any sort at an umpire's decision is unacceptable and the player's punishment for his actions illustrates that fact."
The charge was brought by on-field umpires Ian Howell and Nadir Shah and television umpire AFM Akhtaruddin and Crowe reached his conclusion after a hearing also attended by the three officials, Bangladesh manager Mohammad Shafique-ul-Huque and coach Dav Whatmore.