Trust riverpark manager Chris Mather said 20 units were being installed at jetties, fishing platforms, traffic bridges and boat ramps as part of the 12-month pilot project.
Mr Mather said the riverpark had a small dolphin population that was seriously threatened by discarded fishing line.
‘Three riverpark dolphins have died as a result of injuries caused by fishing waste in the past five years,’ Mr Mather said.
‘A fourth dolphin, Fingers, which has been visiting the riverpark for 20 years, has life-threatening injuries caused by an entanglement of his tail fluke and he has not been sighted since July.’
Native Animal Rescue chief executive Lizzie Aravidis said waterbirds were suffering a similar fate and animal rescuers were dealing with bird entanglements on a weekly basis.
The fishing line disposal units have been installed at Canning Bridge, Applecross jetty and Point Walter jetty. Other units are proposed for Shelley Bridge, Riverton Bridge and other fishing platforms on the Canning River.
All rubbish that is collected during the project will be recorded and correctly disposed of, including the incinerating of fishing line and hooks and recycling lead sinkers.