‘Severe’ marine heatwave recorded around UK and Irish coasts

An alarming new report revealing increased sea warming around the British Isles and Ireland indicates potential challenges for the fish farming sector.

The findings by the European Space Agency suggest that some of the most intense marine heat increases on the planet, up to 4C above expected temperatures for this time of year, have been recorded in coastal waters around the UK and Ireland. The findings are also backed up by the UK’s Met Office.

So far, however, the salmon industry appears to see the warm early summer temperatures as within acceptable risk parameters.

Last summer was the hottest on record and salmon companies in Scotland and Ireland blamed some of their biological problems on those record temperatures.

Water temperatures are up to 3C to 4C above the average for this time of year in some areas, particularly off the UK’s east coast from Durham to Aberdeen, and off north-west Ireland.

The Met Office says the reason is partly human-caused climate change. But other, less-understood natural and man-made factors appear to be driving temperatures up further.

Dr Lynne Falconer, a Research Fellow at the University of Stirling’s Institute of Aquaculture, is currently researching marine heatwave phenomena. She commented: “I’ve been monitoring the satellite and buoy observations over the last weeks, and there is now a severe marine heatwave event occurring in UK and Ireland. Temperatures in some areas are three or five degrees higher than normal for this time of year.

“I haven’t seen an event of this scale before in these waters. This a clear departure from typical conditions and in many ways this is an unprecedented event for the area. The sea temperatures at fish farms will depend a lot on their location and the industry will be keeping a close eye on the temperatures over the next weeks, and beyond.”

Dr Iain Berrill, Head of Technical at industry body Salmon Scotland said: “While some oceans and seas are reporting anomalous temperature spikes, temperatures in the west coast of Scotland and the northern isles are still within normal ranges for salmon. Our salmon farmers are carefully monitoring conditions on their farms and oxygenating the water where appropriate to provide optimal fish welfare.

“Elevated seawater temperatures are being reported right across the globe due to a number of oceanographic and atmospheric reasons. This reminds us of the risk of climate change and the important role aquaculture can play in producing low carbon protein to feed a growing global population without contributing to harmful climate change.”

Rising temperatures are also bringing the prospect of more severe storms which have posed a threat for coastal fish farms in Scotland, Norway and the Faroe Islands in recent years.

The European Space Agency and Met Office findings are also backed by the US agency NOAA (National Ocean and Atmospheric Administration) which said global sea surface temperatures for both April and May were the highest ever recorded, in data that goes all the way back to 1850.