A pelican has been stabbed, dead turtles have been hung up and hooked, and a seagull is walking around with a wooden skewer in its neck in a series of concerning wildlife injuries across Western Australia's south.

While two of the incidents appear to be the result of human littering, the other more serious injuries have been described by wildlife carers as deliberate and malicious.

On the south coast a pelican in Denmark was stabbed with a 30cm-long filleting knife last month, while two turtles near Collie have this week been pictured bloodied and hanging from a road sign next to the Collie River.

Department of Biodiversity, Conservation and Attractions (DBCA) regional wildlife officer Pia Courtis said the Collie River incident was still being investigated.

South West wildlife carer Jessica Berry received a report about the incident and said while she had seen people deliberately kill and display snakes like trophies, she had never seen turtles intentionally killed.

"I have seen pythons have their heads chopped off and displayed in a 'good snake's a dead snake' type scenario," she said.

"But I've never seen people outright hurt turtles.

"Turtles of that size are really old, so to live that long and make it that distance in life only to have that happen to them — it was just rude, it was so bad."

Stabbed pelican rescued and released

While the two turtles in Collie were found dead, the pelican was finally trapped by rangers on Monday, with the knife successfully removed.

DBCA wildlife officer Ian Wheeler said he could only assume the pelican was stabbed on purpose.

"The fact that the knife came in from the top, it would be very difficult for a bird to stab itself," he said.

"So one can only assume that it was actually stabbed when it came too close to a fisherman or someone at the beach."

A pelican that was stabbed with a filleting knife has been released back into the wild. ( Supplied: Carol Biddulph )

Mr Wheeler said rescuers had been overjoyed when they trapped the bird.

"A lot of jubilation, because the bird's given us the run around," he said.

"We spent quite a number of days, and weeks in fact, trying to locate the bird, catch the bird, work out how to catch the bird.

"He was just so elusive."

A seagull in the same area, which is living with a wooden skewer through its neck, has evaded rescuers for the past six weeks.

Sorry, this video has expired Pelican found stabbed with large knife ( Stephanie Downey/ABC News )

Hooks may have drifted

A southwestern long-necked turtle was found in Margaret River on Sunday with three fishing hooks stuck in its body and face, prompting authorities to urge fishers to clean up after themselves.

A southwestern snake-neck tortoise was found dead in Margaret River's Rotary Park, with three fishing hooks in its body. ( Supplied: Jessica Diessner )

Jessica Diessner found the turtle while taking her dogs for a walk in a local park, and uploaded a photo of the mangled turtle to social media.

"[The photo] was pretty horrible. I did feel really bad putting it on there but people need to see it," she said.

"To have big hooks floating down the river is pretty insane. So it was just to make people realise that discarding any sort of rubbish is dangerous for our wildlife."

Ms Courtis said fishing hooks as large as the ones found in the turtle were not used for river fishing, and would have most likely drifted to the area from somewhere else.

'Report first, then post to social media'

While the department appreciated social media was creating awareness around wildlife injuries, Ms Courtis said it was also hampering their investigation.

"We don't have the time to be trawling Facebook to find out what's going on," she said.

A seagull appears unfazed by a large wooden skewer protruding from its neck. ( Supplied: Ashley Lapthorne )

"The information needs to be given to us first-hand so we can put our efforts into investigating what's happened and dealing with any of those incidents quickly."

Ms Courtis said because people were immediately taking to social media, it could seem incidents were increasing, but that might not be the case.

"There are a lot of people posting pictures," she said.

"So whether or not there's an increase in incidents, it's probably more an increase in awareness."