A man found guilty of killing nine little penguins with a blunt object has been fined $82 and sentenced to community service.

It is expected to take several years for the penguin colony to recover from the killings, the court had heard, and a seabird expert has since expressed "extreme disappointment" at the sentence.

Magistrate Tamara Jago said Joshua Leigh Jeffrey, 20, of Tasmania, had committed a “callous act” in striking the penguins.

At the Burnie Magistrates Court on Monday, she sentenced him to 49 hours of community service and ordered him to pay $82.15 in court costs for his involvement in killing the penguins at Sulphur Creek on January 1, 2016.