Ocean Fishes
Capelin
Mallotus vilosus
ALSO KNOWN AS
Capelan (french), caplin, capeling, caplain, ceaplin, roller
DISTRIBUTION
Circumpolar in the Arctic, North Atlantic and Pacific Oceans
ECOSYSTEM/HABITAT
Coastal to open ocean
FEEDING HABITS
Filter feeder
TAXONOMY
Order Osmerifromes (true or freshwater smelts & allies); Family Osmeridae (typical smelts)
SHARE
Capelin may be small, but they have a mighty role to play in northern ocean ecosystems. These small fish are a key forage species for countless marine animals. As an important prey source for Atlantic cod, the health of their populations is linked to the health of many cod populations in Atlantic Canada. Capelin are also part of the diet of animals like halibut, salmon, belugas, dolphins, seals and northern gannets. Additionally, capelin eggs are a food source for certain fish, such as winter flounder. Despite the significance of capelin to marine ecosystems in northern oceans, we still have a lot to learn about these small, forage fish.
Capelin may be small, but they have a mighty role to play in northern ocean ecosystems. These small fish are a key forage species for countless marine animals. As an important prey source for Atlantic cod, the health of their populations is linked to the health of many cod populations in Atlantic Canada. Capelin are also part of the diet of animals like halibut, salmon, belugas, dolphins, seals and northern gannets. Additionally, capelin eggs are a food source for certain fish, such as winter flounder. Despite the significance of capelin to marine ecosystems in northern oceans, we still have a lot to learn about these small, forage fish.
Capelin are small, slender fish that have a pointed snout and a slightly protruding bottom jaw. The topside of their body is olive-green, their sides are silvery and their bellies are a silvery-white colour. During the breeding season males and females have different physical characteristics, which is known as sexual dimorphism. The males during breeding season are slightly larger and have overdeveloped pectoral and anal fins, while females can be recognized by their abdomens that have become swollen with eggs. When full-grown, capelin measure on average between 13 and 20 centimetres long, with the largest males found off the coast of Labrador reaching almost 30 centimetres long.
Some populations of capelin spend the majority of their lives in offshore waters, moving inshore only during spawning season, while other populations spend their whole lives offshore and spawn on the seafloor in deep waters. Different populations also spawn at different times of the year, with some spawning in the spring and some in the summer. Those that come inland to spawn do so in large schools right at the shoreline or in very shallow water. The females will lay their sticky, adhesive eggs right on beaches and banks. Each female can lay between 6,000 to 12,000 eggs during a spawning event. After spawning, adult capelin experience high mortality rates with many dying right on shore.
Capelin eggs hatch after a period of about two weeks, where they remain as larvae in nearshore areas for up to a month before they are swept out to sea on surface currents. Capelin exhibit boom and bust population cycles, in which their populations change rapidly due to changes in environmental conditions. Variables, such as sea surface temperature, prey availability, timing of sea-ice retreat and onshore winds, can have a large impact on the survival of baby capelin each year. Capelin reach sexual maturity around three years of age and live to be about five or six years old. Capelin feed almost exclusively on small plankton-sized crustaceans, and in turn are the main food source for numerous species of fish, including Atlantic cod and halibut, marine mammals and seabirds.
As a schooling fish that comes so close to shore in large aggregations, capelin are easy to catch and can be caught in large numbers. In Newfoundland, locals call this phenomenon a “capelin roll.” Female capelin are targeted for their eggs, called roe, and males are targeted for food, bait and fishmeal. They are used as bait fish in other fisheries, as fertilizer for crops and as a food source in coastal communities, where they are commonly eaten dried, salted, fried or fresh. For thousands of years, communities that harvest capelin held feasts and festivals celebrating this small fish, and they’re still celebrated today.
Capelin are commonly caught by recreational fishers from shore using hand nets when they are most abundant during spawning season. They are also caught by commercial and Indigenous inshore fisheries using purse seines, traps and weirs. In Canada, commercial fisheries for capelin operate in the Gulf of St. Lawrence and off the coasts of Newfoundland and Labrador.
Capelin have not been assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), nor have they been listed under the Species At Risk Act (SARA). Under the Precautionary Approach Framework set out by Fisheries and Oceans Canada, capelin stocks in Atlantic Canada have been assessed as Uncertain due to their complicated population dynamics and modelling uncertainties.
As a critical species for so many other marine animals, including others of commercial value like Atlantic cod, harvest advice for capelin should err on the side of caution to ensure their populations remain stable and healthy. Additionally, given that capelin populations are strongly influenced by environmental conditions, management measures must consider the impacts of climate change and how changing ocean conditions will impact these fish.