Dublin City Council is being urged to put a proper management plan in place to prevent a repetition of last week's diesel spillage in the Bull Island lagoon.
Ms Karin Dubsky, co-ordinator of Coastwatch, said preventing spillages was particularly important at this time of the year when thousands of Brent geese, waders and other birds were wintering in the area.
She estimated the equivalent of a domestic heating oil tank had poured into the lagoon via a stream north of the causeway that connects the island to the Clontarf seafront.
The spill extended nearly a kilometre long.
Ms Dubsky said a boom was only erected at the outlet of the stream some 18 hours after the spillage was first reported to the city council's parks department, which manages Bull Island, Ireland's only UN biosphere reserve.
She said it was difficult to assess the damage. "People in the area were complaining about a strong smell of diesel and the birds were also avoiding it.
"If their plumage was covered in oil, they would start losing heat very fast."
Ms Dubsky said it was fortunate that diesel, unlike crude oil, evaporates quickly. As to where it came from, she said no one had any idea "though someone must be missing it". Calling for proper procedures to be put in place to protect Bull Island's bird population, she said this should be part of a wider plan to manage Dublin Bay.
Ms Dubsky was speaking yesterday on the eve of World Wetlands Day, which is being marked by a Coastwatch symposium at Trinity College.
