Climate change may soon shift the world sea fish stocks dramatically, a new scientific study shows.
Some northern countries may benefit, but shifts of more than 200 kilometres polewards by 2050 will hurt tropical, mostly developing nations badly, according to the study, lead by Dr William Cheung, and presented at the recent American Association for the Advancement of Science (AAAS) conference in Chicago.
“We’ll see a major distribution of many species because of climate change”, said Cheung, a professor at both the University of British Columbia in Canada and the University of East Anglia, citing new computer models for the movements of 1,066 species, 836 of which fish such as herring, tuna, cod and herring, and 230 invertebrates such as crabs and lobsters. “On average, fish will change their distribution by more than 40 kilometres per decade in the next 50 years”, he explained.
“Some species will face a high risk of extinction, including striped rock cod in the Antarctic and St Paul rock lobster in the Southern Ocean,” he added.
Increasing water temperatures, changing currents and rising pH levels (acidity) caused by carbon dioxide emissions were mentioned in the report as factors influencing the movements of fish stocks.
Many of the fish stocks concerned are already considered overfished or threatened by pollution. The added effects of climate change with cod stocks shifting northwards in the North Sea may reduce the biomass by 20 per cent, while the North Sea stocks of the more southerly European plaice might increase by more than 10 per cent, two examples of the upcoming reshuffle. However, the invasion of new species into unfamiliar environments could seriously disrupt ecosystems, the researchers warned.
“The impact of climate change on marine biodiversity and fisheries is going to be huge,” Professor William Cheung summarised the findings. “We must act now to adapt our fisheries management and conservation policies to minimise harm to marine life and to our society. We can use our knowledge to improve the design of marine protected areas which are adaptable to changes in distribution of the species”.
The report was published in the journal “Fish and Fisheries”. According to an earlier study published in that journal, the socio-economic impact could be devastating. Thirty-three nations in Africa, Asia and South America were highly vulnerable to the impact of climate change in fisheries, that report said, adding that 19 of these were already classified by the United Nations as “least developed”.