Didymo making South Island river fish smaller, researchers saySUPPLIED The invasive algae didymo was first identified in South Island rivers in 2004 and has since spread. Didymo is making fish smaller and less abundant, new research shows. The invasive freshwater algae, commonly called "rock snot", has spread to more than 150 South Island waterways since it was first identified in rivers in 2004. Twenty South Island waterways were surveyed. What we can do is try and stop it spreading to other South Island rivers and to the North Island."

Source: Stuff August 16, 2016 06:00 UTC