A two-month-old dolphin calf is now free from entanglement after a huge effort from DBCA rangers and volunteers.
The dolphin, named Koa, was spotted with a net wrapped around its body several times and through its mouth in the Mandurah area recently.
Efforts to disentangle the young dolphin proved difficult as its mother, Anna, was very protective.
"Together with the rangers, Dr Krista Nicholson and our amazing volunteer group assisting in searches, efforts have continued to try to safely disentangle Koa," Estuary Guardians Mandurah posted on social media.
"It is impossible to explain or understand how difficult this actually is, until you are faced with the situation.
"Dolphins are highly mobile animals in a marine environment, are very protective mothers, coupled with variable weather conditions, and highly stretched resources.
"With a gentle guiding tail movement, mother Anna was able to ensure Koa was just out of reach, not understanding we were all there to safely help."
At last the netting began to break and loosen with volunteers spotting Koa on Monday with no visible entanglement.
The local volunteer group is urging people to dispose of their rubbish properly.
"What this calf endured was human caused," Estuary Guardians Mandurah said.
"It highlights we all MUST increase efforts to keep our waterways clean.
"Please join in with any community clean ups, stop and pick up any loose fishing line, rope, netting and litter you see, fish responsibly, and slow down and go around our dolphins!"

Women injured in serious North Dandalup crash
Daughter of man allegedly stabbed to death in East Rockingham pays tribute to father
Peel Thunder claim fourth WAFL premiership
Man dies after suspected stabbing in East Rockingham
City of Rockingham cracks down on illegal dumpers
Missing Mandurah girl found safe and well
Police hunt for man who threatened staff with knife during Falcon armed robbery
Authorities descend on Memorial Drive homeless camp, move on notices issued
Locals asked to have their say on new concept designs for Lakelands Youth Park