The Beacon

Monica's Hot Topics: North Sea Nellies

As a result of climate change, some North Sea fish may be echoing the line of the rapper Nelly circa 2002: "It's Gettin' Hot in Here..."

The fish are being pushed to the limits of their heat tolerance as temperatures continue to rise. Coastal sea surface temperatures in the North Sea have risen by 0.2-0.6 degrees Celsius per decade and on the sea floor by 1.6 degrees Celsius over the past 30 years.

These increasing temperatures are causing approximately two-thirds of the North Sea’s fish to shift in depth and latitude (rather than take their clothes off). On average, a deepening of approximately 3.6 m per decade (some individual species have shifted by as much as 10 m) has been observed in North Sea bottom-dwelling fish along with latitudinal range expansions.

Fish that once were predominantly found in warmer waters to the south of the North Sea, such as sardines and snake pipefish, are now being found in the North Sea due to its rising temperature. Small sharks and rays, such as cuckoo rays and lesser spotted dogfish, have been found to be shifting to deeper waters to escape warming of the shallower waters. Since the North Sea is not very deep, these fish may run out of habitat if sea temperatures continue to increase.

Scientists point out that even if they are able to move north to deeper waters, risks will still arise because these waters contain less available light and greater pressure intensity.

[Image via wikipedia.org]


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