Perth teens recall moment 16-year-old Stella Berry mauled by shark at Swan River trends now

Two teenage swimmers have recalled hearing a 'big scream' after a 16-year-old high school girl was mauled to death by a shark in Perth.

Luke Smith and Joshua Warwick relived the terrifying moment the attack unfolded along the Swan River in North Fremantle, at about 3.30pm on Saturday.

Year 11 student Stella Berry, 16, had been riding a jet ski when she jumped in the water to swim with dolphins and was attacked by a suspected bull shark.

'There was this big scream and then we see a girl just jump off and we see a few fins,' Luke said.

The shark latched onto Stella's leg before swimming away when the 16-year-old was pulled from the water by heroic bystanders before dying. 

Joshua described the scene of chaos that followed with emergency services trying their best to revive the mauled teenager, 9News reported.

'We saw the police running down the hill, and we thought maybe they were chasing someone and then we saw a girl on the ground getting resuscitated,' he said.

Both Luke and Joshua had been swimming at the same spot 10 minutes earlier and said they were unsettled by the realisation they could've been attacked.

Stella's parents Matt and Sophie said they were 'devastated and deeply shocked' by the loss of their 'beautiful daughter'.

'Stella was a vibrant and happy girl with plans of living in Europe after school,' the pair said.

'She was a caring person and was a dear friend to many, across a variety of schools in the area.