Rising sea temperatures have wiped out some of the animals that made their home in Northern Ireland waters 20 years ago.
Scientists have found that seven species typical of cold waters are disappearing from our seas as climate change pushes sea temperatures up.
Meanwhile, 19 warmer water animals are colonising the Irish Sea and north coast.
Northern Ireland’s marine hotspots lie where the icy Arctic waters meet currents from Mediterranean zones. It makes our seas the perfect place to chart changes brought on by rises in sea temperature, according to marine scientist Joe Breen.
“We always talk about Rathlin and the Irish Sea being the meeting point between the cold Artic boreal waters and the warmer influence of the Mediterranean wastes coming up from the south,” the senior Department of the Environment (DoE) sea scientist said. “WWF has described Rathlin as a world biological hotspot.”
Now a new paper published in Marine Environmental Research has charted changes discovered by scuba diving teams in surveys 20 years apart.
Researchers from National Museums NI (NMNI) and DoE Marine Division examined data from Rathlin, the Skerries and Strangford Lough.
Dr Claire Goodwin, NMNI marine biologist, who co-ordinated the later surveys said the warm water species at the extreme northern edge of their range were increasing in number, with 19 species expanding.
Seven cold water species at the extreme southern edge of their range have dwindled.
One, the feather star Antedon petasus, was formerly abundant but has now nearly disappeared.
Mr Breen said the research shows significant changes caused by changes in sea temperatures, which have risen by around 0.6C in 70 to 100 years but most rapidly in the last 20.
He said: “This is positive proof that this is happening, not just in Northern Ireland but all around the world. It shows that temperature rise is happening and is affecting our seas. It will ultimately change the ecology of the Irish Sea and we can’t say whether that change will be positive or negative. What has taken most people by surprise is the speed of this change. I’m seeing change in my lifetime.”
Bernard Picton, Curator of Marine Invertebrates at NMNI, said: “If sea temperatures continue to rise as predicted more species will be affected and this will impact significantly on marine ecosystems.”