Disclaimer: The following suggestions are presented for informational purposes only, and are not intended, nor should be taken, as medical advice. Please consult your doctor if you require medical advice on natural or supplemental forms of Omega-3 essential fatty acids.
Krill oil vs. fish oil
Krill oil has become popular as an alternative to fish oil, in a more easily absorbable form of the Omega-3 essential fatty acids (EFAs) EPA and DHA. Krill oil has the added benefit of choline, an essential micro-nutrient vital for healthy liver function and brain development, and astaxanthin, a carotenoid pigment found in red marine organisms that gives krill its characteristic pink colour. The pigment astaxanthin is an antioxidant claimed to have powerful anti-inflammatory properties.
Krill as keystone species
Most of the krill harvested for its oil is Euphausia superba (Antarctic Krill), tiny, shrimp-like crustaceans that swarm in the cold waters of the Southern Ocean surrounding the continent of Antarctica. Krill oil is derived from the bodies of these pink, opaque crustaceans that feed on phytoplankton, which is abundant due to the upwelling of deep waters in that region.
Krill are a keystone species in the Antarctic and function as a major food source in the marine environment. Krill may measure only about two inches in length on average but they play a vital role in the marine food chain for such tiny creatures, supporting the entire Antarctic ecosystem. Without krill, most of the other life in the Antarctic environment would disappear.
Krill are efficient carbon sequestration units (British Antarctic Survey 2006), play a role in the ocean’s iron recycling process and are a vital component in the marine food chain for species that eat them directly, including fish, penguins, albatross, petrels, squid, seals and baleen whales (the right, minke, fin, sei and humpback species). Other species, including seals and Orcinus orca (Killer Whale) consume species that depend on krill.
Krill is the primary food source for Balaenoptera musculus (Blue Whale) – each blue whale filters up to four tonnes of krill through its baleen plates daily from the ocean. Most krill is harvested near whale feeding grounds. How does krill harvesting impact baleen whales (and other marine species) that require krill as a food source?
How much krill is there?
It is estimated there is between 350 and 500 million tonnes of Euphausia superba (Antarctic Krill) biomass in the Southern Ocean (Meyer et al. 2020). Historically, stocks of Antarctic Krill have declined by 80% since the 1970’s but was unlikely caused by overfishing because krill harvesting was historically a heavily regulated industry (Gross 2005).
Accelerated ice cover loss in the Antarctic region, likely caused by global warming, represents a major decline in the primary food source of krill because, in their larval and juvenile stages, krill feed on phytoplankton living underneath the sea ice.
Approximately half of the krill biomass is eaten by marine organisms, which is then replaced every year by normal cycles of reproduction and population growth. It is estimated there could be up to 10,000 blue whales in the Southern Ocean. At four tonnes of krill per blue whale per day, that is 40,000 tonnes every day, or 14,600,000 tonnes every year.
Is krill in danger of being overfished?
Krill harvesting is on the increase, with global captures tripling since the 1980’s. In the 2019 fishing season, 390,195 tonnes of krill were caught, most of it from the Antarctic Peninsula, the sector most impacted by warming seas and climate change (Meyer et al. 2020). There is concern krill populations are being overfished, with catastrophic follow-on effects in the ocean. Without krill, the entire marine food web in the Southern Ocean would collapse.
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) manage the krill fishery and in October 2020, convened to propose the implementation of additional no-take marine protected areas (MPAs) in biologically rich areas of Antarctic waters to protect krill populations from overfishing (and the impacts of climate change).
A versatile crustacean
Besides the use of krill oil in the pharmaceutical and health industries, krill are harvested to feed livestock, poultry and farmed fish in aquaculture systems. Krill oil as Omega-3 EFA supplements must be from sustainably certified sources.
© 2016 – 2021 Seafood Free September
British Antarctic Survey. (2006, February 6). Antarctic Krill Provide Carbon Sink In Southern Ocean. ScienceDaily. Retrieved August 1, 2021 from https://www.sciencedaily.com/releases/2006/02/060206230630.htm
Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), https://www.ccamlr.org/
Gross, L. (2005). As the Antarctic ice pack recedes, a fragile ecosystem hangs in the balance. PLoS Biology 3(4): 557-561. https://doi.org/10.1371/journal.pbio.0030127
Meyer, B., Atkinson, A., Bernard, K.S. et al. Successful ecosystem-based management of Antarctic krill should address uncertainties in krill recruitment, behaviour and ecological adaptation. Commun Earth Environ 1, 28 (2020). https://doi.org/10.1038/s43247-020-00026-1