What Is Calanus finmarchicus? | Arctic Ruby Oil

Calanus finmarchicus: The Quick Answer

What Is a Copepod?

Copepods are small crustaceans found in marine and freshwater environments throughout the world.

That means Calanus finmarchicus belongs to the same broad animal group as familiar crustaceans such as shrimp, crabs and lobsters, although copepods are vastly smaller.

Calanus finmarchicus belongs to the genus Calanus and the family Calanidae.

It is part of the zooplankton, the diverse community of small animals living in the water column.

The word “plankton” sometimes gives the impression that these organisms simply float passively. In reality, copepods can swim and perform substantial vertical migrations through the water column, although their large-scale geographic movement is strongly influenced by currents.

What makes Calanus finmarchicus especially significant is not its individual size, but its enormous abundance and its central position in the North Atlantic food web.

Where Does Calanus finmarchicus Live?

Calanus finmarchicus is fundamentally a North Atlantic species.

A major scientific review of its distribution documented populations across much of the North Atlantic, from waters near the Gulf of Maine and eastern Canada across the Atlantic to Iceland, the waters around the Faroe Islands, the North Sea and the Norwegian Sea.¹

Important population and overwintering centers have been identified in areas including:

• the Labrador Sea
• the Irminger Basin
• the Iceland Basin
• the Faroe-Shetland Channel
• the Norwegian Sea
• the Norwegian Trench
• deep basins of the Gulf of Maine

Ocean currents play an important part in its distribution. Populations can be transported considerable distances as water masses circulate through the North Atlantic.

The southern Norwegian Sea is particularly important because deep waters there provide a major center for production and overwintering populations. ¹

What Does Calanus finmarchicus Look Like?

To the naked eye, an individual Calanus finmarchicus is tiny. Adults typically measure only about 2–3 millimeters in length. ²

Under magnification, it is clearly recognizable as a small crustacean. It has a translucent, segmented body, long antennae and multiple appendages used in swimming and feeding.

One particularly striking feature can become visible in later developmental stages:

a large internal oil sac.

This oil sac may occupy a substantial portion of the animal's body cavity when its energy reserves are high.

Unlike the fat storage familiar in many terrestrial animals, much of the stored lipid in late-stage Calanus finmarchicus consists of wax esters.

The Life Cycle of Calanus finmarchicus

The life cycle of Calanus finmarchicus is closely synchronized with the seasonal productivity of the North Atlantic.

After hatching from an egg, the animal progresses through six naupliar stages.

It then develops through five juvenile copepodite stages, commonly labeled CI through CV, before reaching the sixth copepodite stage—the adult male or female.^{1, 2}

The first two naupliar stages do not feed. As development continues, the young copepods begin feeding and growing.

Within much of its main North Atlantic range, the life cycle is approximately annual, although timing and number of generations can vary with geography, temperature and food availability.¹

This life cycle contains an extraordinary seasonal strategy.

During the productive part of the year, young Calanus feed, grow and accumulate energy. Later-stage animals can then descend hundreds of meters into deeper water and spend an extended period in a low-metabolism state before returning toward the surface as another productive season begins.

Following the Spring Phytoplankton Bloom

To understand Calanus finmarchicus, it helps to understand the North Atlantic spring bloom.

During winter at high northern latitudes, limited sunlight restricts the growth of phytoplankton.

As daylight increases in spring and conditions become favorable, microscopic phytoplankton can reproduce rapidly, producing a major pulse of biological productivity.

Calanus is adapted to take advantage of this seasonal abundance.

Research has shown a close relationship between Calanus development and the timing of phytoplankton production. ^{1, 3}

By consuming phytoplankton, Calanus takes energy originally captured from sunlight and incorporates it into its own tissues and lipid reserves.

This is one reason Calanus occupies such an important position in northern marine ecosystems.

Why Does Calanus finmarchicus Store Wax Esters?

One of the defining biological characteristics of Calanus finmarchicus is its ability to accumulate large amounts of lipid as wax esters.

A wax ester is formed when a fatty acid is chemically linked to a long-chain fatty alcohol.

This differs from a triglyceride, in which three fatty acids are attached to glycerol.

Studies of Calanus finmarchicus have shown that wax esters become especially important as the animal matures and prepares for its extended period at depth. ^{3, 4, 5}

Wax esters provide a highly concentrated long-term energy reserve.

Researchers studying Arctic and sub-Arctic Calanus species have described them as important converters of energy from phytoplankton into energy-rich wax esters that can then move through the marine food web. ³

The Remarkable Calanus Oil Sac

As later-stage Calanus finmarchicus feed during the productive season, they accumulate lipid inside a conspicuous internal oil sac.

Lipid accumulation begins during the copepodite stages and becomes especially substantial in the later stages as the animal prepares for overwintering. ²

In lipid-rich individuals, this oil sac can occupy a large portion of the body cavity.

Wax esters may account for the great majority of stored lipid in these late-stage animals. Research has reported wax-ester proportions reaching close to 90% of total lipid under some conditions. ⁵

The amount and composition are not constant throughout the year. They vary with developmental stage, season, food supply and geographic location.

This natural oil-storage system is ultimately the biological origin of the wax ester-rich composition found in commercial Calanus oil.

How Calanus Survives the North Atlantic Winter

One of the most remarkable parts of the Calanus life cycle occurs far below the ocean surface.

Many individuals in the fifth copepodite stage, known as CV, descend into deeper water and enter a period of greatly reduced activity and metabolism.

Scientists commonly refer to this dormant or resting period as diapause.

Depending on region, overwintering Calanus may occur hundreds of meters below the surface and, in deep ocean basins, at depths exceeding 1,000 meters.^{1, 6}

During this period, feeding is greatly reduced or absent and metabolism slows substantially.

The animal survives largely on the lipid reserves accumulated during the productive months above.

Those reserves are predominantly wax esters.

When the seasonal cycle turns again, surviving animals return toward productive surface waters, complete development and reproduce.

The wax ester is therefore not an incidental part of Calanus biology. It is closely connected to the species' survival strategy.

Why Is Calanus finmarchicus So Important to the Marine Food Web?

Scientists frequently describe Calanus finmarchicus as a key species in the North Atlantic pelagic ecosystem. ^{1, 7}

The reason is its position between microscopic primary producers and larger animals.

Phytoplankton capture energy through photosynthesis. Calanus consumes phytoplankton and packages some of that energy into nutrient-rich animal biomass and lipids.

Calanus then becomes prey for numerous animals.

In the Norwegian Sea, it is an important food source for commercially important pelagic fish including:

• herring
• mackerel
• blue whiting

Calanus and related zooplankton are also important prey for fish larvae, juvenile fish and other marine predators.

The Norwegian Institute of Marine Research describes Calanus finmarchicus as a keystone species in the Norwegian Sea ecosystem.⁷

In other words, a tiny animal only a few millimeters long helps support organisms millions of times larger than itself.

How Abundant Is Calanus finmarchicus?

Calanus finmarchicus is one of the dominant mesozooplankton species of the North Atlantic and is particularly abundant in the Norwegian Sea.^{1, 8}

Measuring an animal that is only a few millimeters long across an ocean basin is difficult, so estimates vary according to methodology, region and year.

Nevertheless, scientific modeling demonstrates the extraordinary scale of the resource.

A Norwegian Sea ecosystem model published in 2012 estimated annual Calanus finmarchicus production at approximately 29 million metric tons of carbon. ⁸

Norwegian resource assessments and management materials have also cited estimates on the order of approximately 190–290 million metric tons of wet-weight annual production in the Norwegian Sea.

These figures describe production across an immense ecosystem; they should not be confused with the amount commercially harvested.

Commercial catches represent only a fraction of the estimated natural production and are subject to Norwegian management rules and quotas.

Where Do Its Omega-3 Fatty Acids Come From?

The story begins lower in the food web.

Marine primary producers such as phytoplankton are fundamental sources of fatty acids that move through ocean ecosystems.

As Calanus feeds, it acquires and metabolically modifies dietary lipids and stores a substantial portion of its energy in wax esters.

Scientific analyses of Calanus finmarchicus and its oil have identified numerous fatty acids, including the omega-3 fatty acids:

• EPA — eicosapentaenoic acid
• DHA — docosahexaenoic acid
• SDA — stearidonic acid

Unlike conventional fish oil, much of the fatty-acid content of Calanus is stored within wax ester molecules rather than triglycerides.

The long-chain fatty alcohol portion of the wax esters is also an important part of this unusual lipid system.

This is why Calanus oil differs chemically from conventional fish and krill oils even though all three can provide marine omega-3 fatty acids.

How Does Calanus finmarchicus Become Calanus Oil?

Calanus oil is the lipid extract obtained from Calanus finmarchicus.

Because the animal naturally stores so much of its lipid as wax esters, the resulting oil is also predominantly wax ester-based.

Published scientific reviews of commercial Calanus oil describe approximately 80–90% of its lipid fraction as wax esters, although natural composition varies. ⁹

These wax esters contain both fatty acids and long-chain fatty alcohols.

The oil also naturally contains a broad spectrum of fatty acids and carotenoid compounds including astaxanthin.

Calanus oil is therefore not simply purified EPA and DHA extracted from another marine animal.

It reflects the distinctive lipid-storage biology of Calanus finmarchicus.

How Does Zooca Harvest Calanus finmarchicus?

The Calanus oil used in Arctic Ruby Oil is supplied by Zooca® / Calanus AS of Norway.

Zooca has spent more than two decades developing technology for harvesting and processing Calanus finmarchicus.

According to Zooca, the company developed a patented trawl specifically for this unusually small marine resource. ¹⁰

Rather than using conventional fishing gear designed for fish, the harvesting system uses a wide, shallow trawl with mesh designed for collecting Calanus while allowing water to pass through.

Zooca reports that its commercial harvesting season generally runs from approximately May through mid-August in Norwegian waters, although locations and timing vary because Calanus distribution changes with oceanographic conditions.

The harvested material is frozen aboard the vessel before processing.

Zooca completed a dedicated Calanus finmarchicus processing facility in Sortland, Northern Norway, in 2021.

What About Sustainability?

The abundance of Calanus finmarchicus makes it an intriguing marine resource, but abundance alone does not make unrestricted harvesting appropriate.

Calanus is ecologically important precisely because so many other animals depend upon it.

For that reason, commercial harvesting needs to account for both the size of the resource and its function within the food web.

Norway moved from experimental harvesting to a regulated commercial Calanus finmarchicus fishery beginning in 2019.

The fishery operates within Norway's marine-resource management framework, which includes permits, quotas and precautionary management principles.

Zooca states that its harvesting operations comply with these allocated quotas and that its specialized trawling technology is intended to minimize bycatch.¹⁰

Scientific evaluation remains important. Earlier reviews of Calanus utilization specifically emphasized that ecological sustainability should be assessed carefully before large-scale expansion of the fishery. ²

That precaution is appropriate for a species that plays such an important role in the North Atlantic ecosystem.

Calanus finmarchicus and a Changing North Atlantic

Calanus finmarchicus is also important to scientists studying climate-driven changes in the North Atlantic.

Its development, distribution and reproductive success are influenced by factors including:

• water temperature
• ocean circulation
• phytoplankton abundance
• timing of the spring bloom
• seasonal light conditions

Changes in temperature can alter where different Calanus species thrive.

In parts of the northeastern Atlantic and North Sea, warming has been associated with changes in the relative distribution of C. finmarchicus and the more warm-water-associated Calanus helgolandicus.

Because Calanus is a major food source for many fish, changes in its abundance or seasonal timing can potentially affect organisms higher in the food web.

This is one reason Calanus finmarchicus has been studied so extensively by oceanographers and marine ecologists.

What Does Calanus finmarchicus Have to Do With Arctic Ruby Oil?

Calanus finmarchicus is the marine organism from which the Calanus oil in Arctic Ruby Oil is derived.

That distinction matters because Arctic Ruby Oil is therefore not conventional fish oil and it is not krill oil.

Its underlying marine lipid comes from a different organism with a different energy-storage system.

Calanus survives the extreme seasonality of the North Atlantic in part by accumulating large stores of wax ester-rich lipid.

Those naturally occurring lipids contain:

• EPA
• DHA
• SDA
• other marine fatty acids
• long-chain fatty alcohols
• naturally occurring astaxanthin

Zooca® extracts this natural lipid from Calanus finmarchicus for use as Calanus oil.

Arctic Ruby Oil uses that Zooca® Calanus® Oil as its defining marine oil ingredient.

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