Antarctic krill | wwf

Antarctic krill

Antarctic krill (Euphausia superba), Weddell Sea, Antarctica. rel=
Antarctic krill (Euphausia superba), Weddell Sea, Antarctica.
© naturepl.com / Ingo Arndt / WWF

  • Common name

    Antarctic krill

  • Scientific name

    Euphausia superba

  • How they look

    Antarctic krill are small, prawn-like crustaceans. They are one of 85 known krill species. Although their shells have a bright red tinge, krill have a hard, mostly transparent exoskeleton, a segmented body with many legs which they use to swim and eat, and large black eyes. On average, the lifespan of krill is six years but can live up to ten years.

  • Length

    They grow to a length of 6 centimeters (the size of your little finger).

  • Weight

    They weigh up to 2 grams.

  • Distribution

    Antarctic krill are found in the ocean around Antarctica, generally south of 50°S and usually found in the top 200m of the water column.

  • Did you know?

    Adult Antarctic krill can survive more than 200 days of starvation during which they shrink.
    Krill can travel in swarms so dense they can be seen from space. They do so primarily as a defense mechanism to confuse predators that would pick out a single krill. In addition, krill can spend their day at great depths in the ocean and rise during the night toward the surface to avoid predators.

Adélie penguins eat large quantities of Antarctic krill. This Adélie penguin is covered with ... 
	© Michael Harte
Adélie penguins eat large quantities of Antarctic krill. This Adélie penguin is covered with by-products of krill, Paulet Island. December 2008.
© Michael Harte
Antarctic krill are one of the world’s most abundant multi-celled animals. Scientists estimate the biomass of Antarctic krill to be around 380 million tonnes – greater than the weight of all humans on Earth .
They are the key species of most food webs in the Southern Ocean.

Harvested krill is mainly used for the production of krill meal and krill oil, which in turn is used for animal feed and for direct human consumption through health products.

How they behave
Female krill lay up to 10 000 eggs at one time.As krill grow to maturity they gather into swarms (the collective name), sometimes stretching for kilometres in every direction, with many thousands of krill packed into each cubic metre of water, turning the water orange.

These swarms form columns that rise and fall, staying deep in the water during the day and rising to the surface at night. Why swarms are sometimes seen on the surface during daylight hours is unknown.

What they eat
Antarctic krill eat microscopic phytoplankton, single celled plants that drift up near the ocean’s surface. In their larval or juvenile stages of life krill feed on the green algae that grows on the underside of pack ice. Krill are the staple diet of hundreds of different animals, from fish to birds to seals and whales.

Why are krill ecologically important?
Krill plays a key role in the Antarctic ecosystem and are a critical food source for many Southern Ocean species such as whales, seals, fish, penguins and other seabirds. Hence it is important to avoid food competition from the fishery with predators, especially in the vicinity of breeding colonies. There are many current and emerging threats to their conservation and management, including climate change, and future increases in catch limits. Antarctic krill are very sensitive to climate change, including increased temperatures, the loss of sea ice and ocean acidification driven by rising carbon dioxide concentrations in seawater.

Who manages the krill fishery?
Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is the international body responsible primarily for conserving Antarctic marine life.  This includes managing fisheries activities in the Southern Ocean. It is committed to precautionary, ecosystem-based management, meaning that it is responsible for managing the impacts of fisheries on the health, resilience and productivity of the whole ecosystem.

Why is it important to source krill sustainably?

Although the overall population of Antarctic krill is large, fishing takes place in the same areas where many predators live and forage – around the Antarctic Peninsula. It is critical that krill harvesting be done in the most responsible and sustainable way possible to minimise impacts on Southern Ocean ecosystems.

Antarctic krill are very sensitive to climate change. It is critical that the fishery continues to be managed based on sound scientific evidence including understanding the impacts of climate change on current and future krill population sizes.

WWF supports Marine Stewardship Council (MSC) certification as the most robust and credible certification program for wild-capture fisheries. No other certification program provides as high a level of independent, transparent scrutiny on the sustainability of wild-capture fisheries. MSC’s standard recognises the importance of krill to the marine ecosystem.
Crabeater seals (Lobodon carcinophaga) feeding on a school of krill in waters off the western ... 
	© naturepl.com / Steven Kazlowski / WWF
Crabeater seals (Lobodon carcinophaga) feeding on a school of krill in waters off the western Antarctic Peninsula, Southern Ocean.
© naturepl.com / Steven Kazlowski / WWF
Crabeater seals (Lobodon carcinophaga) feeding on a school of krill in waters off the western Antarctic Peninsula, Southern Ocean.

Krill fishing facts

  • Total estimated biomass of Antarctic krill: 379 million tonnes;
  • Estimated krill biomass in Area 48 where krill are caught: 60 million tonnes;
  • Total allowable catch for krill in Area 48: 5.6 million tonnes;
  • Trigger level within which the catch is regulated: 620 thousand tonnes;
  • Catch of krill over the 2014/15 season: 294 thousand tonnes (less than 0.5% of krill biomass in that region).

WWF's work to protect krill

To conserve krill, WWF works with partners and decision-making bodies to implement effective management solutions including:

1. Participating in CCAMLR: WWF participates in annual CCAMLR meetings and works with governments to ensure future management of the krill fishery is undertaken in a precautionary manner based on sound science.

2. Supporting research: WWF is a co-founder of the Antarctic Wildlife Research Fund and supports a range of conservation science projects to understand where penguins and whales feed.

3. Promoting marine protection: WWF, along with other environmental groups, is working with CCAMLR to implement some of the world’s largest MPAs to benefit both krill populations and predators such as penguins, seals and whales.

4. Partnering with experts and industry: We bring experts from science, conservation and industry together to understand and agree on objectives the krill fishery. WWF-Norway partners with industry leaders Aker Biomarine to promote best practices in krill harvesting.  WWF-Australia works with Blackmores, one of Australia’s leading natural health brands, to continue to improve and implement Blackmore’s sustainable fish oil sourcing strategy.

5. Supporting Marine Stewardship Council certification: The MSC label gives consumers a simple way to identify fish products from well-managed fisheries, and gives them the power to make responsible purchasing choices.
   
6. Helping limit impacts of climate change: We actively work with governments, organisations and people around the globe to tackle climate change.
Krill (Thysanoessa spinifera), Nine-mile Bank, San Diego, California, USA. 
	© naturepl.com / Visuals Unlimited / WWF
Krill (Thysanoessa spinifera), Nine-mile Bank, San Diego, California, USA.
© naturepl.com / Visuals Unlimited / WWF