A 24-hour strike by seamen has left Greek ferries and other passenger boats tied up in port. The strike stranded tourists and Greeks heading for vacation, leaving many islands cut off for the day, AP reports.

The PNO seamen’s union called the strike on Wednesday to demand salary increases as part of collective wage agreements. Dozens of inhabited Greek islands are accessible only by sea.

The passenger shipping business association SEEN had expressed surprise when the strike was announced in late June, saying it offered a two percent wage increase for 2019 on top of a retroactive two percent increase for 2018.