Oil and gas exploration should not take place in a firth until its potential impact on wildlife is fully assessed, the Scottish Government has said.
The inner Moray Firth is a protected area
Concerns have been raised about the effect developments in the inner Moray Firth may have on bottlenose dolphins.
Environment Secretary Richard Lochhead has urged the UK Government to heed advice issued by Scottish Natural Heritage (SNH).
It said further work must be done to assess the dolphin population.
Mr Lochhead has made his call in a letter to John Hutton, secretary of state for business, enterprise and regulatory reform.
The environment secretary said: "I appreciate that oil and gas exploration and exploitation is critically important to the Scottish and UK economies, but this needs to be balanced with our environmental responsibilities.
"We must be satisfied that there will be no adverse effect on the integrity of the special area of conservation in the Moray Firth and its local bottlenose dolphin population.
"This is a protected area for these dolphins and a spot that is popular for environmental tourism."
This week, the Whale and Dolphin Conservation Society (WDCS) handed over a petition, postcards and letters containing 18,000 signatures addressed to UK Energy Minister Malcolm Wicks.
The organisation also delivered a statement from 25 top scientific experts concerned for the future of the dolphins.
Oil & Gas UK, a representative body for the sector, has previously said the UK can benefit from the potential of natural resources of the Moray Firth while protecting its wildlife.
Operations director Paul Dymond said the industry was governed by strict regulations.