Head to head
Krill vs Shrimp
Krill and shrimp look alike and are often used loosely as if they were the same thing, and krill are even sold as a food and bait much like small shrimp. Biologically they are separate groups of crustaceans with different bodies and very different lifestyles.
| Krill | Shrimp | |
|---|---|---|
| Classification | One order, Euphausiacea (~85 species) | Several groups (Caridea, Dendrobranchiata, more) |
| Gills | Feathery and exposed outside the body | Hidden under the shell |
| Typical habitat | Open water; whole life pelagic | Mostly on or near the sea floor |
| Feeding | Filters phytoplankton with a leg basket | Mostly omnivore and scavenger |
| Grouping | Enormous swarms | Loose aggregations or solitary |
| Light organs | Present in many species | Rare |
| Size | Mostly 1 to 2 cm; Antarctic krill to 6 cm | A few mm to over 30 cm |
| Role for people | Fishmeal, omega-3 oil, aquaculture feed, bait | Major seafood worldwide |
Krill vs Shrimp: common questions
Are krill just small shrimp?
No, though they are easy to mistake for them. Krill are a separate order of crustaceans, the Euphausiacea, not a size class of shrimp. They differ in anatomy, most obviously in having feathery gills exposed on the outside of the body rather than hidden under the shell, and in lifestyle, spending their entire lives swimming in open water and feeding by filtering microscopic algae, whereas most shrimp live on the bottom and scavenge. The confusion comes from their similar shape and small size and from the fact that krill are harvested and sold in ways similar to small shrimp.
Which is more important to the ocean, krill or shrimp?
Krill, by a large margin, at least in the polar and temperate open ocean. Antarctic krill alone amount to an estimated several hundred million tonnes and form the single link between the phytoplankton of the Southern Ocean and its large animals: baleen whales, crabeater and leopard seals, all the Antarctic penguins, many seabirds, and much of the fish and squid depend on krill directly or at one remove. Shrimp are ecologically important on reefs, in estuaries, and on the deep-sea floor as recyclers and as prey, but no single shrimp species anchors an ecosystem the way Antarctic krill does.
Can you eat krill, and what does it taste like?
Yes, krill is edible and is eaten directly by people in parts of Japan, Russia, and the Philippines, usually the newly caught animals, and krill meal and krill oil are widely sold, the oil as an omega-3 supplement. Krill has a strong, salty, slightly bitter shellfish flavour, more intense and less sweet than shrimp, and the shell is thin. Most of the world catch, though, is not eaten by people at all: it goes into feed for farmed salmon and shrimp, where it improves growth and adds pink colour, and into pet and aquarium food. The shell's high fluoride content and rapid spoilage after catching have limited krill as a mass human food.