Scientists have witnessed a massive resurgence in the sea lamprey population in the River Tamar on the Devon/Cornwall border and have recorded five times more fish than the seasonal average.
They picked up the increase in lamprey numbers while recording migrating salmon at Gunnislake,
The EA welcomed the resurgence as it indicates a healthy river environment and said the metre-long sea lamprey is a primitive marine species that comes into rivers to spawn.
The eel-like fish has a jawless mouth and is boneless with a skeleton made of flexible cartilage.Lamprey are thought to be more sensitive to pollution than salmon so their presence on any river system is to be encouraged.
For centuries the fish was considered a delicacy in