Fish have lost half their average body mass and smaller species are making up a larger proportion of European fish stocks as a result of global warming, a study published Monday has found.
“It’s huge,” said study author Martin Daufresne of the Cemagref Public Agricultural and Environmental Research Institute in Lyon, France.
“Size is a fundamental characteristic that is linked to a number of biological functions, such as fecundity – the capacity to reproduce.”
Smaller fish tend to produce fewer eggs. They also provide less sustenance for predators – including humans – which could have significant implications for the food chain and ecosystem.
A similar shrinking effect was recently documented in Scottish sheep and Daufresne said it is possible that global warming could have “a significant impact on organisms in general.”
Earlier research has already established that fish have shifted their geographic ranges and their migratory and breeding patters in response to rising water temperatures. It has also been established that warmer regions tend to be inhabited by smaller fish.
Daufresne and his colleagues examined long-term surveys of fish populations in rivers, streams and the Baltic and North Seas and also performed experiments on bacteria and plankton.
They found the individual species lost an average of 50 percent of their body mass over the past 20 to 30 years while the average size of the overall fishing stock had shrunk by 60 percent.