Gavin Morgan

19 April, 2008

POOR breeding seasons suffered by Shetland’s seabirds could be caused by warming seas reducing the availability of food, according to new research.

Scientists from the NAFC Marine Centre, in Scalloway, have noticed an abundance of warm water plankton around the isles’ shores, due to temperature changes.

At the same time seabirds in Shetland have had breeding seasons which are “up and down”, with some being extremely unsuccessful.

Dr Ian Napier, of the NAFC, said: “The immediate cause of the seabird breeding failures is generally believed to be a shortage of food. They have trouble finding sand eels to feed their chicks.

“Probably what is happening is that there is some change in the ocean which is reducing the availability of food and also increasing warm water, but we don’t really know the details of what the cause is.”

Coastal waters the UK have been getting warmer since the 1980s. Around Shetland the temperature has risen by up to 0.4 degrees per decade, a trend which scientists believe will continue.

A direct scientific link between increasing plankton and less food for birds has not been established, but preliminary results show that there is a coincidental connection.

“We are still analysing the data in detail, but it appears that in years when there is more warm water plankton the seabirds do less well,” Dr Napier said.

“It appears that it may be linked, but it is not simply that there is less food because of more plankton. The warm water plankton is like an indicator, when there are more of them it indicates that something has changed.”

The species of plankton being found usually occur to the south in the Bay of Biscay region, but evidence shows they have been flourishing northwards in the last 20 years.