Ocean warming causing fish to head north, spawn earlier: new research report
"Economic and political consequences can be severe"
A new research report shows that some fish are moving north 10 times faster than land animals due to ocean warming.
For their report, scientists looked at how marine life is responding to the warming of the oceans and shifting its distribution, combing through hundreds of published papers to compile a global database of how sea life is responding to regional and global climate change.
The three-year project, whose findings were published in Nature Climate Change journal, shows that shifts in marine life are widespread and comparable to, or even greater than, those on land, a news release from the Scottish Association of Marine Sciences said.
The shifts include changes in the distribution of fishes, corals and other marine life, and also changes to the times of year that marine events such as spawning take place.
One of the report’s lead authors, Mike Burrows from the Scottish Association of Marine Sciences, said the study was “the most comprehensive review of published reports of the effects of climate change in the sea.”
“Most of the effects we saw were as expected from changes in climate. So, most shifts in the distributions of, say, fishes and corals, were towards the poles, and most events in springtime, like spawning, were earlier. Despite the increase in temperatures in the ocean being smaller than on land, the changes in ecology were every bit as evident in the sea, and sometimes even bigger.”
Among numerous observations, the research found that, over a 40-year period, the global average of marine species displacement was 75 kilometres, which is up to 10 times the figure for species movement on land.
The most noticeable effects in the oceans were seen among phytoplankton, zooplankton and bony fish.
“Some of the biggest shifts in relation to changing climate were in the North Sea, with some fish and plankton shifting northwards at up to 200 km per decade over the last 50 years” said Mike Burrows.
More than 80 per cent of all the observations were consistent with the expected impacts of climate change.
“The effects of climate change on marine life might not be immediately visible,” Burrows said. “[But] “the economic and political consequences can be severe.”
The report will be be used by the United Nations Intergovernmental Panel for Climate Change, set to produce its next climate assessment in 2014.