What is krill and why do we care about it?
This is a common question! If you walk down the aisle of a grocery story in Average Town, USA, it is easy to find cans of tuna and sardines. Would you be able to find cans of krill next to the tuna? Or would they come in glass jars in another section of the store? Most likely, you aren't going to see them anywhere obvious. However, in some countries such as Japan and Russia, your local grocer would carry these items as part of their regular stock for human consumption. But wait - if you looked really carefully at some of the products that are commonly found in that Average Town, USA supermarket, you might be surprised to find that krill is on the ingredient list. So what are krill, and why should we care about them?
What is krill?
Krill are small (5-6 cm) shrimp-like crustaceans that are found throughout the worlds oceans. Not surprisingly, Antarctic krill (Euphausia superba) are found in the Southern Oceans surrounding Antarctica. They can form large swarms in open ocean regions, or more scattered layers under the ice edge. Krill also follow a diel vertical migration - they move up towards the ocean surface at night, and back down into deeper water during the daytime hours. Antarctic krill are filter feeders that consume algae (phytoplanton); at the bottom of the food chain, they serve as the plant grazers of their ecosystem. More information can be found on the Wikipedia webpage about Antarctic krill .
Krill casserole for dinner?
Perhaps you aren't planning on serving krill casserole tonight, but there are many reasons why krill are important to us and the health of our planet.
For example, did you know that if you wander through the pharmacy section of an Average Town, USA supermarket, the odds are you can find several products with krill as a major item in the ingredient list? Many of those products proudly display "Antarctic krill"! Next time you are shopping for joint pain relief, check out the labels on Nature's Way "EfaGold Krill Oil" softgels (recommended for "cardiovascular and joint health"), or TwinLab's "Krill Essentials Joint Krill Oil" softgels. These are just a few of the brands you'll see sporting the benefits of krill. Better yet, if you want some brain food, Dr. Weil in Time Magazine recommends omega-3 fatty acids, commonly found in fish, however his preferred source is .... you guessed it, Antarctic krill oil. In Dr. Weil's Q & A section on Antarctic Krill, he notes that it lacks the "fishy taste" and might be better "for lowering cholesterol". Marketed for yet another audience, the "100% pure Neptune Krill Oil" (aka "The Power of Krill") will "rapidly relieve" PMS symptoms.
Even the mega-superstores - online and traditional - are carrying krill products. Amazon.com is carrying krill products in all kinds of forms. At last check, there were 161 listings under the "Health & Personal Care" category, representing 19 brands; some of these were also listed under "Grocery". There was even one item in the toy section: "Giant Microbes Krill (Euphausia superba) Aquatics Plush" for only USD 7.00! [UPDATE! On April 4th, 2009, Amazon listed a whopping 414 items under "Health & Personal Care", 11 under "Grocery", 34 listings in "Pet Supplies", and two under "Toys"!] Costco sells MegaRed, purportedly "3x more powerful than fish oil for supporting cardiovascular health" - this item is often featured as a full page ad in their monthly sales magazine.
While some of these uses are not yet supported by stringent (or even extensive) scientific studies, research projects are underway to determine the validity behind some manufacturers claims. Results from one study conducted in Canada was recently published in the Journal of American College of Nutrition (2007:Vol 26, No. 1, pages 39-48). According to that study, "NKOTM at a daily dose of 300 mg significantly inhibits inflammation and reduces arthritic symptoms within a short treatment period of 7 and 14 days".
Next time you are ordering a pizza, ask them to hold the sardines, to be replaced with an extra handful of krill. Well, perhaps not from your local pizzeria, but a company in Ukraine (Sandypool Ltd) sells "fresh frozen krill peeled meat" in bulk for "pizza, seafood salads and restaurant entrees." Are you hungry yet? In other countries, krill is a more noticeable item in the supermarket: they offer canned Antarctic krill the same way we supply canned tuna.
To meet consumer demands of "markets in pharmaceutical, food, and aquaculture industries", Aker BioMarine (Norway) is projecting a phenomenal catch of 1,200 metric tons during their first year using a new USD 170 million krill supertrawler; given the substantial upfront financial commitment they've made, it is unlikely their first year will be their last. In June 2007, they signed an agreement to sell their Qrill product to a major US distributor, and additional agreements to supply their products to distributors in Sweden and Finland too.
It appears that those small cold-water crustaceans have crept into our stores without much pomp and circumstance, perhaps in places we didn't really expect to find them, but they are there nonetheless.
Krill is also eagerly consumed by a captive audience - literally! Dried whole, dried powdered (both from Aqion, LLC) and frozen krill (Aqua-In-Tech) are sold to commercial and recreational aquarists throughout the world. Krill Meal is the "feed ingredient for the future" in the aquaculture community. For the home aquarist, krill also offers the ability to "vitalize coloration" - hard to pass up that opportunity! This market spans large commercial hatcheries to small household aquarists, and is used not just for feeding fish, but for feeding exotics including turtles and reptiles.
Web of Life
|Table 1. Partial list of krill consumers (direct and indirect) within the Antarctic ecosystem
- Antarctic fur seals
- crabeater seals
- leopard seals
- chinstrap penguins
- macaroni penguins
- gentoo penguins
- Adelie penguins
- fin whales
- blue whales
- humpback whales
- minke whales
- Antarctic jonasfish
- C. myersi icefish
- graytail skate
- blunt scalyhead
- Antarctic Petrel
- common diving petrels
- Georgian diving petrels
- dove prions
- giant petrels
- cape petrel
- black-browed albatross
- southern fulmar
- spiny icefish
- mackeral icefish
- ocellated icefish
- painted notie
- Antarctic silverfish
- N. ionah glassfish
Now let's take a step back and look at nature's view of the significance of krill. The Antarctic ecosystem is krill-centric: Antarctic krill is the key prey species for many animals, including seals, whales, seabirds, fish and squid. Table 1 shows just a partial list of animals for which krill (directly or indirectly) are a principal component of their diet. If you could ask a chinstrap penguin what's on the menu for dinner tonight, the response would be an enthusiastic "krill!" Ditto for Antarctic fur seals and crabeater seals - their dining plans all include krill. Indeed, some of these animals feed exclusively on krill; for others, their diet includes krill and krill predators. For example, the black-browed albatross eats krill, but it also eats numerous fish species, some of whom incidentally forage primarily on krill.
What would happen to the Antarctic ecosystem if the krill population were significantly diminished? Imagine going to the supermarket and finding the shelves mostly empty ... and then trying another store, and another, only to find the same thing: little to no food. Without krill, those species dependent on krill would suffer, and their populations become vulnerable to rapid decline. Therefore, it is important to determine the role that krill plays in the Antarctic ecosystem, and how it's population size varies over time. We need to know where krill are at different times of the year, what factors influence krill abundance, including fishery impacts, and how krill predators utilize this essential food resource. Finally, we need to assure that krill are not overharvested to the point where the supermarket for krill-dependent species is bare.
Shopping List: Milk, Fruit, Krill, ...
While it may not be krill casserole for dinner tonight - or tomorrow - there is a good chance that it is on your shopping list, in one form or another. Certainly throughout the world there is a large demand for Antarctic krill, especially since humans have entered the consumer market for "pink gold". We are krill consumers, in some cases we just don't know it. Yet in many countries, Antarctic krill is as common as canned tuna is in the USA. Worldwide, and especially in the US, the public demand for omega-3 has been met in part by importing Antarctic krill. Krill use in aquaculture supports our demand for fish in our diet, a food item that continues to gain popularity for all the health benefits associated with its consumption. Finally, krill are a keystone species of the Antarctic ecosystem, one that cannot be replaced. So despite their unobtrusive size, they are quietly embedded in consumer markets worldwide, and are critical to the health of our planet. For these reasons, it is in everyone's best interest to make sure that Antarctic krill are not overharvested - that is why we care.
More information on how the US AMLR Program and the AERD conduct research in support of ensuring a balanced Antarctic ecosystem can be found on the following webpages: AERD and the US AMLR Program, Research Programs, and Research Surveys.
Disclaimer: Naming or mentioning herein of any company or product (generic or brand), or purported results from the use of any product (generic or brand), does not indicate endorsement, support, or proof of concept by the AERD, the US AMLR Program, the SWFSC, the NMFS, the NOAA, the DoC, nor any other US government agency or entity. Products are shown to demonstrate ingredients only.
Want more details? Some suggestions for further reading are below, and on the AERD publications page:
A compilation of parameters for ecosystem dynamics models of the Scotia Sea - Antarctic Peninsula region. CCAMLR Science 14:1-26. Hill SL, K Reid, SE Thorpe, J Hinke, GM Watters (2007).
A first step towards modelling the krill-predator dynamics of the Antarctic ecosystem. CCAMLR Science 13: 217-277. Mori M, DS Butterworth. (2006).
A model at the level of the foraging trip for the indirect effects of krill (Euphausia superba) fisheries on krill predators. Ecological Modelling 105: 235-256. Mangel M, PV Switzer. (1998).
Aggregation Patterns of Pelagic Predators and their Principal Prey, Antarctic Krill, near South Georgia. The Journal of Animal Ecology 62(3): 551-564. Veit RR, ED Silverman, I Everson. (1993).
Albatross Populations In Peril: A Population Trajectory For Black-Browed Albatrosses At South Georgia. Ecological Applications 16(1): 419-432 Arnold JM, S Brault, JP Croxall. (2006).
Antarctic krill and ecosystem management - from Seattle to Siena. CCAMLR Science 9: 175-212. Miller DGM. (2002).
Consideration of major issues in ecosystem monitoring and management. CCAMLR Science 9: 213-232. Everson I. (2002).
Diet, provisioning and productivity responses of marine predators to differences in availability of Antarctic krill. Marine Ecology Progress Series 177: 115-131. Croxall JP. (1999).
Effects of sea-ice extent and krill or salp dominance on the Antarctic food web. Nature 387: 897-900. Loeb V, V Siegal, O Holmhansen, R Hewitt, W Fraser, W Trivelpiece, S Trivelpiece. (1997).
Environmental change and Antarctic seabird populations. Science 297:1510–1514. Croxall JP, PN Trathan, EJ Murphy. (2002).
Environmental response of upper trophic-level predators reveals a system change in an Antarctic marine ecosystem. Proc. Royal Society Biol. Sci. 268(1465): 377-384. Reid K, JP Croxall. (2001)
Modelling Southern Ocean ecosystems: krill, the food-web, and the impacts of harvesting. Biological Reviews 81: 581-608. Hill SL, EJ Murphy, K Reid, PN Trathan, AJ Constable. (2006).
Spatial Structure of the Southern Ocean Ecosystem: Predator-Prey Linkages in Southern Ocean Food Webs. The Journal of Animal Ecology 64(3):333-347. Murphy EJ. (1995).
Summer diet of demersal fish at the South Shetland Islands. Antarctic Science 9(4): 407-413. Takahashi M, T Iwami. (1997)