Fish introduced into rivers by human intervention over the past 150 years have modified the average body size of fish assemblages in many areas of the world. A study conducted by researchers from CNRS, the University of Toulouse, IRD and MNHN, as well as the universities of Antwerp (Belgium) and Utrecht (the Netherlands), shows that non-native fish are larger than native species by an average of 12 cm.
It’s long been known that the introduction of non-native species can be a disaster for the local plants and animals. Witness the damage that rabbits have caused in Australia or gray squirrels in The United Kingdom.
Freshwater fish have their fair share of horror stories with Lake Victoria in particular being damaged beyond repair.
In this study the authors show how the introduction of non-native freshwater fish has increased the average size of the fish population. (Most introduced fish are for food and sport, species which tend to be large and tasty!)
Read more here – Science Daily