The City of Fremantle will be closing a number of beaches near the new traffic bridge after a school of bull sharks were filmed in the area earlier this week.
Vision taken by construction workers near the old Fremantle traffic bridge shows a school of baby sharks in water below.
The Department of Primary Industries and Regional Development confirmed the sharks in the vision were likely to be bull sharks.
The SharkSmart website has tracked the school since Monday, with two sightings recorded less than 24 hours apart at the same location.
The public reports estimate the sharks to be between 1.5 and two metres in length.
“DPIRD is monitoring the situation and will have a boat on the water tomorrow as part of its shark tagging research program in the Swan Canning Estuary,” a spokesperson