Pacific Herring

By Archives •  Updated: 07/14/22 •  3 min read

The Pacific herring, Clupea pallasii, is a species in the herring family with non-spined fins and a deeply forked caudal fin. Its name comes from the Latin root clupea meaning ‘herring’. Pallasi refers to Russian naturalist and explorer Simon Pallas.

The Pacific herring in British Columbia spawns along beaches from February to July and mostly in March. Female herring produce about 19000 eggs when they reach 19 cm in length and 30,000 eggs when they reach 22 cm. A large herring weighs about 500 grams.

It is the immense number of herring that school along a few beaches and the enormous number of eggs that they lay that attract so many predators. There are reports of spawning occurring along 250 kilometers of beach in British Columbia.

Eggs are laid between the high tide line to a depth of about 10 meters. The sticky eggs appear like tiny beads adhering to the rocky substrate, waterlogged branches and submerged vegetation.

Pacific Herring Description

There is a single dorsal fin located mid-body and a deeply forked tail-fin. Their bodies are compressed laterally, and ventral scales protrude in a somewhat serrated fashion. Unlike other genus members, they have no scales on their heads or gills.

The Pacific herring can grow up to a length of almost 18 inches in exceptional cases and weigh up to 19 ounces, but a typical adult size is closer to 13 inches. The fish interior is quite bony with oily flesh.


During spawning, for many kilometres around, the water turns milky white with the milt from the males. The eggs hatch after about 10 to 14 days. Larval herring eat diatoms and copepods and fall prey to filter-feeding invertebrates, jellyfish, and other small fish.

The diet of the larval herring includes planktonic barnacles and molluscs, and bryozoans. Large schools of herring begin to form through the summer while the herring grow large feeding on copepods. Young herring are abundant at the edge of the Fraser River plume in May and June where large concentrations of small plankton occur

First-year herring remain in the Strait of Georgia for their first year and swim to the west coast of Vancouver Island at 2 or 3 years of age where they mature into adults. Growth is faster on the west coast of Vancouver Island but it is more dangerous there because of the large number of predators than in the Strait of Georgia.

Thousands of birds and hundreds of marine mammals gather from February to May in southern British Columbia to feast on herring or their eggs. The late winter spectacle of wild animals mingling among the fishing fleet is one of the greatest wildlife spectacles in the North Pacific.

The spawning event repeats many times along the western shore of North America as different schools of fish leave the depths of the ocean for a brief attempt to spawn.


Hourston, A.S. and C.W. Haegele, Herring on Canada’s Pacific Coast, Canadian Special Publications of Fisheries and Aquatic Sciences, Department of Fisheries and Oceans, Ottawa (1980)

J.H.S. Blaxter, The Herring: a Successful Fish?, Journal of Canadian Journal of Fish. Aquatic Sci.(suppl. 1) 42:21-30 (1985)

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