Half the population lives within five miles of a waterway
British Waterways is asking the public to keep a record of the wildlife they see around the River Severn and the Gloucester and Sharpness Canal.
It is hoped the information from the annual survey will help ecologists to understand where species live and how best to protect them.
The particular focus of this year's survey is native species of bumblebee.
The Bumblebee Conservation Trust said: "Three of Britain's 25 species of bumblebee are now nationally extinct."
It is part of British Waterways' 6th wildlife survey of the South West.