According to a study fish have lost half their average body mass and smaller species are increasing tremendously as a result of global warming. Study author Martin Daufresne of the Cemagref Public Agricultural and Environmental Research Institute in Lyon, France, told that the small size is huge in number as size is a fundamental characteristic that is linked to a number of biological functions, such as fecundity – the capacity to reproduce.
It is observed that 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. Researchers found that the individual species lost an average of 50 per cent 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.
Daufresne said that this was a result of a decrease in the average size-at-age and an increase in the proportion of juveniles and small-sized species. He added that it was an effect observed in a number of organisms and in a number of very different environments – on fish, on plankton, on bacteria, in fresh water, in salt water – and we observed a global shrinking of size for all the organisms in all the environments.
