SERIOUS concern has been expressed over what impact the Poole Harbour oil spill could have on the unique wildlife of Brownsea Island.

Oil from Sunday’s pipeline leak has washed up on the shores of Brownsea Island – a protected site of special scientific interest – with owners National Trust saying it would keep its beaches closed.

A National Trust spokesperson said: “A thin film of oil was located on parts of the west and north shores of Brownsea Island [on Tuesday, March 28]. This was dealt with immediately by the authorities, and we continue to support however we can.

“We ask visitors to follow the safety advice issued by the harbour commissioner and to avoid entering the water around Poole Harbour. The beaches on Brownsea Island remain closed for now.

Bournemouth Echo: Oil visible in the water of Poole Harbour after oil leak.Oil visible in the water of Poole Harbour after oil leak. (Image: PA)

“Brownsea Island is a part of an internationally important wetland and marine conservation zone, and is a haven for wildlife, including oystercatchers and sandwich terns.

“We remain seriously concerned about the impacts of the spill on wildlife populations and the varied habitats they depend on. We're carefully monitoring the situation.”

As one of the few places in southern England where indigenous red squirrels survive, Brownsea Island additionally holds international importance to wintering and summer-nesting birds.

Approximately 200 barrels of reservoir fluid were released after the leak at the Wytch Farm oil field, run by company Perenco, on Sunday.

At least 15 birds have been spotted with brown oil smudges on their feathers since the leak.

Bournemouth Echo: Shelduck with brown oil smear after leak in Poole Harbour.Shelduck with brown oil smear after leak in Poole Harbour. (Image: Ian Ballam/RSPB)

Perenco has said the 200 barrels contained 158 litres of liquid made up of 85 per cent water and 15 per cent oil. If correct, this equates to around 4,740 litres of oil.

The spill still has major incident status. On Tuesday, Poole Harbour Commissioners (PHC) said the urgent clean-up operation had covered 36 miles (58km) of shoreline by helicopter, drones, boat and shore patrols.

Perenco has temporarily suspended its operations at Wytch Farm following the incident and is involved in the clean-up operation.

Dorset Wildlife Trust, which manages much of Brownsea Island, has been approached to comment.