Krill: Uncover the Taxonomy, Ecology, and Uses

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Krill are pretty small, but they’re an important part of the ecosystem. They’re also a great source of omega-3 fatty acids, and humans eat them too.

Krill are small crustaceans found in all oceans of the world. The largest populations are found in the southern ocean of Antarctica, where they can reach up to 500 million tonnes. They’re also bioluminescent, meaning they can produce light.

In this article, I’ll tell you all about krill, their role in the ecosystem, and how they’re harvested.

What are krill

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What in the World are Krill?

Krill is a Norwegian word that means “small fry of fish,” which is attributed to the fact that krill are small crustaceans found in the ocean.

Types of Krill

There are over 80 species of krill, but the most common one is the Antarctic krill (Euphausia superba). Other species of krill can be found in different parts of the world, such as the black krill (Thysanoessa longipes) found in the Pacific Ocean and the bamboo krill (Euphausia pacifica) found in the waters around Rhode Island.

Where Krill are Found

Krill are found in all of the world’s oceans, but the largest populations are found in the Southern Ocean around Antarctica.

The Role of Krill in the Ecosystem

Krill are a vital part of the ocean’s food chain, serving as a food source for many marine animals, including whales, seals, penguins, and fish.

Krill in Different Languages

The word “krill” is used in many languages, including Afrikaans, Arabic, Belarusian, Bulgarian, Catalan, Chinese, Czech, Danish, Dutch, Georgian, German, Hebrew, Icelandic, Indonesian, Italian, Japanese, Kazakh, Korean, Latvian, Lithuanian, Norwegian, Occitan, Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Tagalog, Turkish, Ukrainian, Vietnamese, and Welsh. In Serbian, it is written as “srpskisrpskohrvatski.”

Unusual Facts About Krill

  • Krill can grow up to 6 centimeters long.
  • Krill are bioluminescent, meaning they can produce light.
  • Krill are filter feeders, using their legs to filter tiny organisms from the water.
  • Krill are a rare source of omega-3 fatty acids, which are essential for human health.
  • Krill are sometimes called “ocean’s cattle” because of their abundance and importance in the food chain.

What Causes Krill to Thrive?

Krill thrive in cold, nutrient-rich waters. They are most abundant in areas where there is upwelling, which is the movement of cold, nutrient-rich water from the deep ocean to the surface.

The Role of Krill in Human Life

Krill are used in some countries as a food source for humans, but they are more commonly used as a food source for animals. Krill oil is also used as a dietary supplement because of its high concentration of omega-3 fatty acids.

What’s in a Name? The Taxonomy of Krill

Krill, those small crustaceans that occur in oceans all over the world, are known by a number of different names. In Japan, for example, they are called okiami, while in Russia they are known as kril. But regardless of what they are called, krill are an important source of food for many animals, including fish, whales, and penguins. In fact, it is estimated that the largest krill species, Euphausia superba, can occur in numbers of up to 500 million tonnes in the Southern Ocean alone.


Krill belong to the order Euphausiacea, which includes a number of different families and genera. The two main genera of krill are Euphausia and Thysanoessa, with Euphausia being the largest and most commonly found. Within these genera, there are a number of different species, including Euphausia superba, which is the species most commonly associated with krill fishing operations.

Physical Characteristics

Krill are small crustaceans, typically measuring between 1 and 6 centimeters in length. They have a long, slender body with a thoracic exoskeleton and a number of legs attached to their thorax. Krill are able to filter feed on small particles of food, including phytoplankton and other small animals, and are known for their highly developed compound eyes.

Distribution and Habitat

Krill occur in oceans all over the world, with the largest populations found in the Southern Ocean around Antarctica. They are also found in the Pacific and Atlantic Oceans, as well as in the waters around Japan and other regions. Krill are able to live at depths of up to 1,000 meters, although they are most commonly found in the upper layers of the ocean.

Harvesting and Conservation

Krill have been harvested for food and other purposes for many years, with the Soviet Union and Russia being the largest krill fishing nations in the world. Today, krill are harvested for a number of different purposes, including as a food source for humans and animals, as well as for the production of krill oil, which is a popular dietary supplement. However, there are concerns about the impact of krill harvesting on the environment, and a number of conservation and experimental operations have been started to foster sustainable krill harvesting practices.

Ecology of Krill: The Small but Mighty Players in the Ocean’s Food Chain

Krill are unique in their ability to convert large amounts of carbon from phytoplankton into a form that can be consumed by other animals. They do this by actively consuming phytoplankton and other small particles, filtering them through their fine, hair-like structures called setae. This process is known as the “biological pump,” and it plays a key role in the ocean’s carbon cycle. Krill also actively transport dissolved organic carbon from the surface to deeper waters, where it can be consumed by other organisms.

The Physical Characteristics and Distribution of Krill

Krill are typically found in large groups, or swarms, that can contain millions of individuals. They are physically adapted to survive in the harsh Antarctic environment, with a unique set of features that allow them to thrive in the cold, dark waters. These features include large compound eyes that can detect both white and dark objects, and a circulatory system that allows them to filter out particular elements from the water. Krill are also able to vertically migrate through the water column, depending on the availability of food and suitable environmental conditions.

The Different Species of Krill and Their Morphology

There are over 85 species of krill, which are placed in the superorder Eucarida and the family Euphausiidae. The most common species of krill is Euphausia superba, which is found in the Southern Ocean. Other species include Bentheuphausia amblyops, Thysanoessa inermis, and Nemato-brachion boops. Krill have a unique morphology that includes a segmented body, two pairs of antennae, and a long, thin tail. They are also known for their bright, translucent coloration, which helps them to blend in with their surroundings.

The Impact of Krill on the Ocean’s Food Web and Research on Krill Consumption

Krill are an important food source for many animals in the ocean, and changes in their population can have a significant impact on the food web. Research has shown that krill consumption by larger animals such as fish can be affected by changes in the availability of krill, resulting in changes to the entire ecosystem. Despite their importance, krill are still relatively rare and poorly understood. Further research is needed to fully understand the role that krill play in the ocean’s ecosystem and how they can be better protected.

From Ocean to Plate: Krill in the Kitchen

Krill is literally the main ingredient in some dishes, especially in Asian cuisine. Here are some examples:

  • Krill soup: A popular soup in Korea made with dried krill, vegetables, and seasonings.
  • Shrimp and krill dumplings: A dim sum dish in China made with shrimp, krill, and other ingredients.
  • Krill fried rice: A simple yet flavorful dish made with rice, krill, and vegetables.
  • Bagoong paste: Filipino cuisine uses krill in a special paste that flavors a lot of dishes.

Krill as a Feed for Plants and Animals

Krill is not only used in cooking but is also an essential food source for many animals and plants. Here are some examples:

  • Whales and baleen whales: These animals feed on krill to survive.
  • Oceanic life: Many oceanic creatures, such as penguins, seals, and squid, depend on krill as a food source.
  • Plants: Krill is also used as a fertilizer for plants because it is high in nitrogen and carbon dioxide.

Is Krill a Healthy Addition to Your Diet?

Multiple studies have shown that krill oil can have a positive impact on health. Some of the research has found:

  • Krill oil can help reduce symptoms of pain and inflammation, including joint pain and menstrual pain.
  • Krill oil can help reduce levels of triglycerides, which are a type of fat that can increase the risk of heart disease.
  • Krill oil can help improve brain function and reduce symptoms of depression and anxiety.

How Krill Oil Compares to Fish Oil

Krill oil and fish oil are both sources of omega-3 fatty acids, but there are some key differences between the two. Krill oil:

  • Contains higher levels of EPA and DHA in a form that is more easily absorbed by the body.
  • Contains phospholipids, which are not found in fish oil.
  • Is less likely to cause negative side effects, such as fishy burps or digestive issues.

The Importance of Choosing a High-Quality Krill Oil

Not all krill oil supplements are created equal. When choosing a krill oil supplement, it’s important to look for:

  • A high concentration of EPA and DHA.
  • A high concentration of phospholipids.
  • A supplement that has been tested for purity and contaminants.

Possible Negative Effects of Krill Oil

While krill oil is generally considered safe, there are some potential negative effects to be aware of:

  • Krill oil can increase the risk of bleeding, especially when taken in combination with blood-thinning medications.
  • Krill oil can cause digestive issues, such as diarrhea or upset stomach.
  • Krill oil can be expensive compared to other supplements.

How to Incorporate Krill Oil into Your Diet

Krill oil supplements are sold in a variety of forms, including capsules and liquid. They can be found in health food stores and online. Krill oil can also be found in some prepared foods, such as energy bars and convenience foods.

If you want to add more krill to your diet, you can also try:

  • Eating more seafood, such as shrimp or crab.
  • Following a diet that includes a variety of natural, whole foods.
  • Taking a high-quality krill oil supplement.

Krill: Fascinating Facts You Didn’t Know

  • The word “krill” comes from the Norwegian word “krill” which means “small fry of fish”.
  • In some languages, krill is called “Euphausiacea”, which is derived from the Greek words “eu” meaning “good” and “phausis” meaning “light”, referring to the bioluminescent body of the animal.

Krill Species and Composition

  • Krill is actually composed of several species, belonging to the family Euphausiidae.
  • The largest species of krill is called Bentheuphausia amblyops and can measure up to 6 inches in length.
  • Krill is a type of crustacean and is closely related to shrimp and lobsters.

Krill’s Importance in the Ocean

  • Krill is a critical item in the marine food web, as it is a major source of food for many animals, including whales, seals, penguins, and birds.
  • Despite its small size, krill is found in large swarms and can actually be one of the most abundant animal populations on Earth, with some estimates putting the population size in the trillions.
  • Krill is also important for the ocean’s plants, as it is a major source of the nutrient iron.

Krill’s Distinctive Features

  • One of the most distinctive features of krill is its bioluminescent body, which can emit light in response to certain behaviors.
  • Krill also has a gestation period of just a few days, which is one of the shortest of any animal.
  • Krill can be found in both coastal and deep waters, making it a versatile animal.

Krill’s Role in Changing Climate and Habitat

  • Krill is a threatchanging climate and habitat, as it is highly dependent on the presence of sea ice for its habitat.
  • Krill regularly migrate in massive swarms, traveling deeper during the daytime and shallower at night, which is a behavior known as diel vertical migration.
  • Krill is also an important food source for humans, as it is an omnivore and can eat a variety of different foods.


Krill are small, crustacean-like animals found in the oceans of the world. They’re a vital part of the ecosystem and a food source for many marine animals, including whales and penguins. You can’t avoid them, so just be glad they’re there!

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Bitemybun's family recipes with complete meal planner and recipe guide.

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Joost Nusselder, the founder of Bite My Bun is a content marketer, dad and loves trying out new food with Japanese food at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.