Exotic warm water marine species such as anchovy, bluefin tuna, stingray, and thresher shark are spreading northwards into British coastal waters, where average sea temperatures are now moving closer to the warmer conditions of southern Europe. (See this article from September 2011 detailing the sighting of a Thresher Shark near the Isle of Mann in the Irish Sea: http://www.tagsharks.com/thresher-shark-sighting-near-the-isle-of-man).
A new study by marine scientists discloses that many species, some better known to holidaymakers in the Mediterranean and the Canary Islands, are now increasingly commonly seen in the seas off Cornwall, Devon, Hampshire and Sussex, providing vivid evidence that climate change is already changing the natural environment.
Off south-west England, fishermen and biologists see bluefin tuna, triggerfish, stingrays, thresher sharks and ocean sunfish in greater numbers. Off the south coast, and in some cases the North Sea, anchovies, red mullet, sea bass and John Dory are now being caught in commercial quantities as these warm water species shift north.
In the North Sea, more trawlers are now fishing for increasingly abundant squid, another staple of Mediterranean restaurants, than are targeting traditional species such as cod and haddock.
But the marine climate change impacts partnership (MCCIP) report, published by UK and Scottish government ministers, warns that there are serious and potentially dangerous challenges for native species and for the fishing industry, as they struggle to adapt and ward off threats from invasive species and unusual diseases.
"The truth is that climate change is having a big impact on distribution of fish stocks and this is going to present some significant challenges for policymakers, fisheries managers and for fishing industry itself," said Richard Benyon, the UK minister for the marine environment.
Benyon told the Guardian that a "whole-seas approach" was now needed. "If fish aren’t in certain parts of the sea, but are going to be elsewhere, we need to have fisheries management policies that will make sure that they are sustainable, wherever they are. We realise these are fast-moving ecosystems and we have to be smarter."
The study, a "report card" on the latest scientific data and its implications, says trawlers will have to travel far further north within 20 years to catch Britain’s favourite species, the cod, as they follow cold waters northwards, while warmer waters threaten to devastate commercial mussel fisheries.
Conflicts between British and foreign fleets could become more common in future, it added. A major row over control of north-east Atlantic mackerel stocks between the European Union and the Faroese and Icelandic governments could be a sign of things to come both in European waters and around the world.
Fleets from France and Spain are now expected to head into the Channel, chasing anchovies, which have been disappearing from the Bay of Biscay, to the dismay of south coast fishermen.
This could also have implications on marine conservation using spatial measures: in the Baltic Sea, spawning cod had been deserting a closure area at Bornholm that was originally set up to protect them.
To read the full article, follow this link: http://www.guardian.co.uk/environment/2012/may/08/warm-water-species-speading-northwards