Two foreign tourists who sped down Venice’s Grand Canal on motorized surf boards Wednesday have been heavily fined and the boards have been confiscated, city authorities said.

The mayor’s office said in a statement that the two were fined €1,500 ($1,971) each over the incident, and the city’s attorney is preparing further action against them for damaging the city’s image.

Earlier, Mayor Luigi Brugnaro posted a video on social media showing a pair of surfers heading down the famed waterway as the sun rose in the distance. The mayor asked for help in apprehending what he called “two overbearing imbeciles who are making a mockery of the city,” and promised dinner for anyone who identified the scofflaws.

Venice has long suffered over-tourism, and has a long list of rules governing the behavior of visitors.

The city fined two German travellers US $1,000 in 2019 for making coffee on the 430-year-old Rialto Bridge. Visitors also are prohibited from swimming in the canals and from eating on the steps of monuments. or face fines.

From next year, day-trippers will have to pay a visitor’s tax to help offset the elevated costs of providing services in the canal city.