The capelin or caplin (''Mallotus villosus'') is a small forage fish of the smelt family found in the

North Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for ...

North Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the contine ...

and

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

oceans. In summer, it grazes on dense swarms of

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

at the edge of the ice shelf. Larger capelin also eat a great deal of krill and other

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s. Among others,

whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...

s, seals,

Atlantic cod The Atlantic cod (: cod; ''Gadus morhua'') is a fish of the family Gadidae, widely consumed by humans. It is also commercially known as '' cod'' or ''codling''.Atlantic mackerel,

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

and

seabird Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...

s prey on capelin, in particular during the spawning season while the capelin migrate south. Capelin spawn on sand and gravel bottoms or sandy beaches at the age of two to six years. When spawning on beaches, capelin have an extremely high post-spawning mortality rate which, for males, is close to 100%. Males reach in length, while females are up to long. They are olive-coloured dorsally, shading to silver on sides. Males have a translucent ridge on both sides of their bodies. The ventral aspects of the males iridesce reddish at the time of spawn. The closest relative of the capelin appears to have been the extinct fossil genus '' Enoplophthalmus'', which inhabited Europe during the

early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

and

early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

Capelin migration

Capelin populations in the Barents Sea and around

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

perform extensive seasonal migrations. Barents Sea capelin migrate during winter and early spring to the coast of northern Norway (

Finnmark Finnmark (; ; ; ; ) is a counties of Norway, county in northern Norway. By land, it borders Troms county to the west, Finland's Lapland (Finland), Lapland region to the south, and Russia's Murmansk Oblast to the east, and by water, the Norweg ...

) and the

Kola Peninsula The Kola Peninsula (; ) is a peninsula in the extreme northwest of Russia, and one of the largest peninsulas of Europe. Constituting the bulk of the territory of Murmansk Oblast, it lies almost completely inside the Arctic Circle and is border ...

(Russia) for spawning. During summer and autumn, capelin migrate north- and north-eastward for feeding. Icelandic capelin move inshore in large schools to spawn and migrate in spring and summer to feed in the

-rich oceanic area between Iceland,

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

, and

Jan Mayen Jan Mayen () is a Norway, Norwegian volcanic island in the Arctic Ocean with no permanent population. It is long (southwest-northeast) and in area, partly covered by glaciers (an area of around the Beerenberg volcano). It has two parts: la ...

. Capelin distribution and migration is linked with

ocean current An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, sh ...

s and water masses. Around Iceland, maturing capelin usually undertake extensive northward feeding migrations in spring and summer, and the return migration takes place in September to November. The spawning migration starts from north of Iceland in December to January. In 2009, researchers from Iceland made an interacting particle model of the capelin stock around Iceland, successfully predicting the spawning migration route for the previous year.

Reproduction

As an r-selected species, capelin have a high reproductive potential and an intrinsic population growth rate. They reproduce by spawning and their main spawning season occurs in spring but can extend into the summer. The majority of capelin are three or four years old when they spawn. The males migrate directly to the shallow water of fjords, where spawning will take place, while the females remain in deeper water until they are completely mature. Once the females are mature, they migrate to the spawning grounds and spawn. This process usually takes place at night. In the North European Atlantic spawning typically occurs over sand or gravel at depths of , but in the North Pacific and waters off

Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...

most spawn on beaches, jumping as far up land as possible, with some managing to strand themselves in the process. Although some other fish species leave their eggs in locations that dry out (a few, such as plainfin midshipman, may even remain on land with the eggs during low tide) or on plants above the water ( splash tetras), jumping onto land '' en masse'' to spawn is unique to the capelin, grunions, and grass puffer. In beach-spawning capelin populations, after the female capelins have spawned, they immediately leave the spawning grounds and can spawn again in the following years if they survive. The males do not leave the spawning grounds and potentially spawn more than once throughout the season. Beach-spawning male capelin are considered to be

semelparous Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered ''semelparous'' if it is characterized by a single reproduction, reproductive episode before death, and ''iteroparous ...

because they die soon after the spawning season is over. In ocean spawning capelin populations, it has been observed that both male and female capelin are semelparous and die after spawning. This difference observed between capelin populations shows that capelin are physiologically capable of an iteroparous or semelparous reproductive mode depending on spawning habitat. Studies on two populations of Newfoundland capelin which spawn in two distinct habitats found a lack of evidence of genetic variability between beach and deep-water spawners. This provides support for the species being facultative spawners. Capelin may select optimal spawning location based on abiotic factors such as temperature range and sediment. The optimal temperature range for capelin eggs that leads to greatest hatching success and offspring quality appears when eggs are incubated between . This optimal temperature range provides support that individual capelin are able to select spawning location based on temperature, as temperature is one of the most variable factors between beach and deep-water spawning habitats for capelin. There is also evidence that shows that temperature is not the only factor at play when it comes to selection of spawning habitat. When both habitats are simultaneously experiencing temperatures in the optimal range, capelin are found to spawn in both habitats. This may be an advantageous strategy that leads to increased fitness. Capelin have been observed to spawn at beaches when deep-water or subtidal habitat is lower than and spawn in deep-water habitats when beach habitats temperature is consistently above .

Diet

Capelin are planktivorous fishes that forage in the pelagic zone. Studies analyzing diet in populations of capelin in both the arctic marine environment as well as in west Greenland waters show that their diet consists upon primarily euphausiids, amphipods, and copepods. As capelin individuals grow, the composition of their diet changes. Smaller capelin primarily consume smaller prey (copepods) and shift their diet towards feeding on primarily larger euphausiids and amphipods as body and gape size increases. The sufficient distribution and abundance of these zooplankton is necessary for capelin to meet energy requirements for progressing through many stages of their life cycle. Capelin occupy a similar dietary niche as polar cod, which leads to a potential for interspecific competition between the two species.

Fisheries

Capelin is an important forage fish, and is essential as the key food of the

Atlantic cod The Atlantic cod (: cod; ''Gadus morhua'') is a fish of the family Gadidae, widely consumed by humans. It is also commercially known as '' cod'' or ''codling''.Atlantic herring in the Barents Sea, capelin seem to be heavily affected. Probably both food competition and herring feeding on capelin larvae lead to collapses in the capelin stock. In some years, though good recruitment of capelin despite a high herring biomass suggests that herring are only one factor influencing capelin dynamics. In the provinces of

Quebec Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...

(particularly in the Gaspé peninsula) and

Newfoundland and Labrador Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the populatio ...

in Canada, it is a regular summertime practice for locals to go to the

beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from Rock (geology), rock, such as sand, gravel, shingle beach, shingle, pebbles, etc., or biological s ...

and scoop the capelin up in nets or whatever is available, as the capelin "roll in" in the millions each year at the end of May or in early June. Commercially, capelin is used for fish meal and oil industry products, but is also appreciated as food. The flesh is agreeable in flavour, resembling herring. Capelin roe (''masago'') is considered a high-value product in Japan. It is also sometimes mixed with

wasabi Wasabi (Japanese language, Japanese: , , or , ) or Japanese horseradish (''Eutrema japonicum'' syn. ''Wasabia japonica'') is a plant of the family Brassicaceae, which also includes horseradish and Mustard plant, mustard in other genus, genera. ...

or green food colouring and wasabi flavour and sold as "wasabi caviar". Often,'' masago'' is commercialised as '' ebiko'' and used as a substitute for '' tobiko'', flying fish roe, owing to its similar appearance and taste, although the mouthfeel is different due to the individual eggs being smaller and less crunchy than tobiko.

Citations

General and cited references

Capelin off Iceland: Biology, exploitation and management
* {{Authority control Canadian cuisine Commercial fish Fish described in 1776 Fish of the Arctic Ocean Greenlandic cuisine Osmeridae