The association said a monitoring system could be placed on ferries

The director of the Scottish Association for Marine Science said it was needed to measure the amount of nutrients, salt and plankton in water.

Professor Graham Shimmield spoke to the environment committee, which is holding an inquiry into the marine environment.

The only monitoring system in UK waters is located in Liverpool Bay.

Professor Shimmield said: "These could be put in ferries which are sailing the same routes every day or in buoys in the sea.

"At the moment, we just don't have any observations to help the development of models."

Other European countries such as Ireland, Holland and Germany already have such systems in place.

Contrary to the impression you might get from the emotion and perceptions in the press, we're harvesting our stocks sustainably Scottish Fishermen's Federation

The professor added that they would take "several million" pounds to set up, but this was relatively low compared with the economic impact of the fishing industry in Scotland.

SNP environment spokesman Richard Lochhead criticised the absence of any such equipment at the moment.

"It's outrageous that Scotland, with 25% of Europe's waters, does not have a monitoring system in place to measure the impact of climate change, unlike Ireland, France, Germany and Holland," he said.

Bertie Armstrong, chief executive of the Scottish Fishermen's Federation, told the committee that the industry was in a healthy state.

He said: "The industry has changed over the last few decades, and especially in the last decade, in a way that is a response to conservation issues.

"We now find in ourselves in a position with a Scottish industry that is about the right size.