The Marine Climate Change Impacts Partnership -- a group combining scientists, government departments, nongovernmental organizations and the fishing industry -- in its annual report card for 2012 said the dominant cold-water zooplankton species in the North Sea had declined 70 percent since the 1960s, while many plankton species had moved 10 degrees of latitude north in the same period. That equates to a distance of nearly 700 miles.
At the same time, deepwater species like monkfish had moved steadily deeper to keep cold, while shallow-water species like sole had moved steadily higher with the warmth.
The MCCIP report card also noted that some fish species had already moved north 30 to 250 miles over the past 30 years and said that by 2050 they could have added a further 135 to 375 miles.
Sole, seemingly perversely, has moved south against the trend. In previous winters it always migrated north from the Dutch coast's shallow waters, which became unbearably cold in winter while the deeper North Sea remained relatively warm. Now it stays put as the water remains warm throughout the year.
The warming waters also appear to be a boon for squid, and in Scotland many trawlers are switching to hunting that.
The changing movements and ranges of commercially exploited fish stocks have also produced some unexpected conflicts, with trawlers having to follow the fleeing fish farther afield and into the territories of other nations. This has already happened with mackerel moving from off Norway to off Iceland, while Spanish trawlers are starting to venture into U.K. waters in search of anchovy.
Some winners, some losers
"The model predictions suggest that Iceland and Greenland -- Greenland in particular -- and Norway are probably going to benefit in terms of fisheries from climate change, at least for the next 50 to 100 years," Pinnegar said.
"Things like the cod populations are projected to really boom further north, and it is already starting to happen," he added. "The herring populations are projected to do quite well, too. Those are really big commercial stocks.
"From the modeling that has been done, it looks like the U.K. is almost at the break-even point. We gain some species and we lose some species. But in terms of our fisheries, it will probably balance out almost," he said.
But with the good comes the bad. Invasive species such as the zebra mussel have been extending their ranges northward, and some marine-borne bacteria usually associated with warmer water are also expected to move in.
The marine impact section of the U.K. government's Climate Change Risk Assessment particularly notes the possibility of Vibrio cholerae, associated with outbreaks of cholera in humans from eating contaminated shellfish, arriving in force off U.K. shores as the temperature climbs. There have already been outbreaks in Spain, and scientists in the United Kingdom are on watch.
It also warns of the potential arrival of other water-borne Vibrios such as V. parahaemolyticus, which is associated with seafood bacterial gastroenteritis in humans. This is already very common in the United States, with more than 10,000 cases in a year, against about 40 in the United Kingdom.
"Assessments based upon global sites suggest that changing climatic conditions could result in increased rates of infection and illness in humans via shellfish and through bathing," it says.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500