Mandurah's resident dolphin calf Luca has died after becoming entangled in fishing line for the third time this year.
Luca became entangled in fishing line again on August 20 with officers from the Department of Biodiversity Conservations and Attractions working alongside volunteers in an effort to free him.
With the condition of his dorsal fin deteriorating, Luca sadly passed away after another attempt to disentangle the calf on Friday morning.
The River Guardians group announced the sad news on Facebook.
"Luca's health was severely compromised and unfortunately he died this morning while undergoing medical treatment for the severe fin wounds caused by repeated fishing line entanglements," the post read.
"Please remember to always dispose of your fishing line and other waste responsibly."
In a post on Facebook, Estuary Guardians also expressed their heartbreak at the news of Luca.
"Please know the rescue today went smoothly and successfully but right at the end Luca slipped away," the post read.
"The vets did everything they could. It is now known through X-rays Luca had underlying health issues.
"We know everyone cared deeply. Please allow us and yourselves (time) to grieve."