There are 130 dolphins in the colony

Each year, they attract thousands of tourists, while bringing in almost �750,000 for the local economy.

But a report by the Moray Firth Partnership - a coalition of 550 local organisations - is to warn that damage to the environment is putting their future in doubt.

The group says that dolphins are being poisoned by toxic pollution, and that some have been drowned in illegal salmon nets. It also warns that their food is now in short supply because of the collapse of fish stocks in the North Sea.

The group says radical changes are needed to halt the decline.

Steadily shrinking

Last year, a leading naturalist warned that the colony could starve to death in the Moray Firth.

Tony Archer, of the Moray Firth Wildlife Centre in Spey Bay, also claimed the world's most northerly pod of the dolphins might disappear from the Highland coastline in less than 50 years unless steps were taken to help them.

He said the group was steadily shrinking due to pollution, human interference from boats and a lack of fish - with the poor availability of food the main worry.

The Moray Firth pod lives in colder waters than any others - this is the most northerly colony on Earth.

The UK's only other resident dolphins live in the waters of Cardigan Bay, off West Wales, although they are visitors to inshore waters round several parts of the British Isles.