SHOCKING video of whale sharks, rays and whales being slaughtered by tuna fishermen has been released by an industry whistleblower.

The never-before-seen footage shows protected marine life caught as bycatch, then killed after being lured into massive purse-seine nets by Fish Aggregating Devices, nicknamed death magnets.

The whistleblower, who worked as a spotter onboard a tuna fishing boat in the Pacific said marine species, such as dolphins, manta rays, marlin and whales, were caught almost every time FADs were deployed.

Greenpeace Ocean Campaigner Nathaniel Pelle said the majority of canned tuna eaten in Australia is caught in this manner.

WA shoppers eat more canned tuna than any other seafood, despite evidence that overfishing has pushed stocks into serious decline, with some on the brink of collapse.

Mr Pelle is urging WA consumers to demand retailers stock more sustainable tuna varieties, such as Safcol, which sources tuna not caught using FADs or purse-seine nets.

“Greenseas should be congratulated for recently pledging to stop using FAD-caught tuna by 2015, but that’s several years away,” Mr Pelle said.

“Brands like John West, Coles and Woolworths have refused to make any such commitments.”

Woolworths' media relations manager Benedict Brook said the company offer pole and line caught tuna in its private label brands.

"It is disappointing that Greenpeace has chosen to ignore this fact," Mr Brook said.

On its website John West states it is committed to supplying products that ensure the sustainability of marine resources. Their product compiles with dolphin safe requirements and they are part of the Marine Stewardship Council which works to ensure fish stocks are managed for the future.

In August, Coles said it had launched Australia's first responsibly sourced tuna brand. "The new Coles Brand tuna is hand caught by pole and line from small fishing vessels using a traditional method which avoids catching other fish or marine life and minimizes the impact on the ocean," a media statement said.

The video has emerged as the Western and Central Pacific Fisheries Commission prepare to meet to discuss the management of the Pacific’s tuna’s industry.

Nearly 60 per cent of the world’s tuna comes from the Pacific Ocean and the species is being pushed to extinction from overfishing.

Save our Marine Life spokesman Tim Nicol said too few people are aware of the devastating impacts of irresponsible fishing practices and overfishing.

"We need to ensure marine life has safe places to feed and breed. This can only be done by creating a network of marine sanctuaries that are proven by science to protect marine life and restore our damaged fish stocks," Mr Nicols said.

"Currently less than 1per cent of our waters are protected in marine sanctuaries."

Greenpeace say the UK canned tuna market has committed to not source tuna from operations using FADs.