Red mullet and John Dory, two species that may increase in the North Atlantic Ocean. (Photo: University of Bristol/Stock File/FIS)
Atlantic fish species already shifting due to warming waters
Friday, September 16, 2011, 23:50 (GMT + 9)
Fish stocks in the northeast Atlantic Ocean are already shifting due to warming waters. The move is harming some fish stocks but benefiting others, according to research published this week in Current Biology.
Led by Dr Steve Simpson of the University of Bristol in collaboration with researchers from eight other institutions, this “big picture” study is the first to combine a suite of European datasets, which included more than 100 million fish, to analyze how climate change is affecting the commercially important European fishery. Researchers examined 28 years of fisheries agency data from 11 independent surveys spanning more than 1 million sqkm of the European continental shelf.
Warming in the northeast Atlantic has been taking place at a rate four times the global average over the past 30 years.
"While a 1.3° Celsius change in mean annual temperature in the North Sea over the past three decades may sound trivial, temperature has a strong influence on egg maturation rates, growth and survival of fish larvae, and impacts on the planktonic communities that underpin the food webs that sustain commercial fisheries,” explained Simpson, a researcher in the University's School of Biological Sciences.
The shallower waters of the North Sea, between the UK and Denmark, have experienced the greatest change thus far, Earth Times reports.
"We see many more southerly warm-water species faring well on the European shelf than northerly cold-adapted species. This means more small-bodied, faster growing species with shorter generation times, and potentially more diversity," he continued.
The data show that fish in European waters have already gone through intense community-level changes related to dramatic regional warming trends. A massive 72 per cent of common fish species have undergone a change in abundance related to rising sea temperatures.
Of those fish, three out of every four species have seen their populations grow.
Catches of species that prefer cold waters, such as haddock and cod, have dropped by half in the past three decades, while landings of warm-loving and exotic species, including red mullet, hake and sole, have more than doubled. Europeans will thus be seeing more changes when shopping for seafood as waters continue to heat up, BBC reports.
According to the research, studies focused merely on shifts to where particular fish species are found -- which will overlook the much more ecologically and economically pertinent effects of warming.
"We may see a further decline in cold-adapted species, many of which were the staple for our grandparents. The flip side is a likely increase in species that for the UK may seem relatively exotic now, such as red mullet and John Dory,” Simpson foreshadowed.
“Over time, with effective management and an appropriate response in consumer demand, European seas have the potential to yield productive and sustainable fisheries into the future," he concluded.
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