These tiny shrimp-like creatures are the linchpin in the Antarctic food web,

sustaining a huge number of species, from penguins to humpback whales.

They're also increasingly the target for human consumption.

A growing krill industry has been scooping up the crustaceans

for use in fish oil supplements and fish feed.

Scientists and conservationists fear that could further imperil Antarctic wildlife.

[ DIRECTOR OF ANTARCTIC AND SOUTHERN OCEAN CONSERVATION FOR THE PEW CHARITABLE TRUSTS, ANDREA KAVANAGH]: "Antarctic krill are the keystone species in the Southern Ocean. Krill connect all the other species down there. It's impossible to overstate the importance of krill."

This perceived abundance has led global fishing fleets to target Antarctic krill.

Vessels from China, Norway, South Korea, Ukraine and Chile trawl the region's choppy waters from December to July.

Under established rules within the Antarctic Treaty System, trawlers must stay largely confined to four areas off the Antarctic Peninsula.

And a seasonal catch is capped at 680,000 tons.

But polar scientists say the current limits may not go far enough to safeguard the food supply for wildlife.

Some also say there are indications that the fleet's activity is harming wildlife.

[ DIRECTOR OF ANTARCTIC AND SOUTHERN OCEAN CONSERVATION FOR THE PEW CHARITABLE TRUSTS, ANDREA KAVANAGH]: "For the first time ever, it was reported that there were bycatch in the krill industry of whales, three juvenile humpback whales, and it's actually unknown how they came about to be caught by these continuous suction trawlers. It's, they were definitely in poor body condition. They were starving. So they suspect perhaps that the humpbacks were actually following the krill trawlers to try to get krill and somehow got caught up in their systems of nets. But it seems really troubling that there were actually three of them that were caught this year when that's never happened before."

The fishing company - Norway's Aker BioMarine - says it has since reinforced its ships' devices to keep marine mammals out of its nets.

The krill industry is set to grow significantly in the next decade.

Fish farming, which uses krill as feed, is the world's fastest growing food sector.

And the krill oil market is projected to rise to more than $900 million by 2026. That's according to a report by Global Industry Analysts.

[ DIRECTOR OF ANTARCTIC AND SOUTHERN OCEAN CONSERVATION FOR THE PEW CHARITABLE TRUSTS, ANDREA KAVANAGH]: "We're really concerned because the krill fishery is overly concentrated in certain areas around the Antarctic Peninsula. And that means that they are taking a lot of fish from very small areas where all the predators are also congregated. So we have huge colonies of penguins and the krill fishery is operating right off the shores of these colonies."

Mindful of the threat krill fishing poses to penguins, eight companies have pledged to stay at least 19 miles away from key breeding colonies during incubation and chick-rearing season.

But even without competition from fisheries, the krill supply is under increasing pressure due to climate change.

[GREENPEACE OCEANS CAMPAIGNER, LOUISA CARSEN] "We're already starting to see a debate amongst scientists, you know, between climate change and industrial fishing, what's having a greater impact? But just like across our global oceans, it's the combination of different stresses that is so difficult for wildlife across the oceans and why we need to see those ocean sanctuaries and creating those safe havens for wildlife."