Pacific Herring

Clupea pallasii

Pacific Herring

Clupea pallasii

At the Aquarium

Sandy Coast

Appearance

These fish have countershading, with a darker olive or blue back and lighter, silver sides and belly. They have a single dorsal fin on their back and a forked tail.

Habitat

Adults live in open coastal and offshore waters in huge schools of millions of fish. They are deeper in the water column during daylight and rise towards the surface at night.

Diet

Zooplankton and phytoplankton in nutrient-rich waters associated with upwelling

Life History

Migrate into estuaries in winter or spring for group-spawning, depositing eggs on kelp, eelgrass, rocks, and other structures. On average, each female lays 20,000 sticky eggs. This spawning event is so huge that sometimes a milt cloud can be seen for days after. It takes about 10 days for a 0.3 inch larva to hatch. The hatched larvae remain in their spawning grounds for 2-3 months, and then metamorphose into the juvenile form. In the fall, these juveniles then swim to deeper waters. The juveniles school with one another for 2 to 3 years, and then join schools of adult herring when they reach maturity. Pacific herring can reach a maximum length of 10 inches in the Puget Sound and live to 15 years, while herring in the Bering Sea can reach 13 inches long and live up to 20 years.

IUCN Status

Data Deficient

Ecosystem & Cultural Importance

  • These fish are integral to all trophic levels of marine food webs in the Eastern Pacific. The eggs and larvae are a primary food source for many invertebrates, juvenile fishes, and sea ducks and gulls. Juvenile and adult herring are the primary prey of harbor seals, sea lions, Coho and Chinook salmon, Pacific Cod, Pacific Whiting, Lingcod, and Pacific Halibut.
  • These fish are culturally important. Many First Nation communities have traditional stories and songs about Pacific Herring. The fish and its eggs were harvested in large quantities and traded.
  • Pacific Herring have been harvested commercially since the 1800s. It is used for food and as bait.
Beaufort Sea, Alaska to Baja California, Mexico. They are also found in the Western Pacific and in the Russian Arctic from the Chukchi Sea to the White Sea.
These fish might be caught recreationally from docks and piers. Their arrival to spawn in bays is accompanied by the presence of many seabirds looking to eat the fish and/or their eggs.
The sizes and life spans of Pacific Herring vary within their range. Herring in the southern part of the range are smaller, mature earlier, and die younger than those farther north. In addition, the peak spawning time is late winter through spring, with progressively later spawning times farther north. When predators are attacking, these schooling fish may form a ‘bait ball’ or ‘herring ball,’ with the individual fish all trying to get into the center of the ball. Agile and fast divers, such as auklets and guillemots, will dive into the water and attack the school from the sides and underneath, while gulls will try to grab fish when the ball is at the surface. Sea lions, dolphins, and whales are also drawn into the action.

Citations & Other Resources

  • Alaska Department of Fish and Game: https://www.adfg.alaska.gov/index.cfm?adfg=herring.main
  • DeMARTINI, EDWARD E., and PAUL C. SIKKEL. inchesp. 483-523. In: The Ecology of Marine Fishes: California and Adjacent Waters. 2006. LG Allen, DJ Pondella, and MH Horn (eds.). University of California Press, Berkeley, 670 pp.
  • IUCN Redlist website: https://www.iucnredlist.org/species/98471199/98845541
  • NOAA Fisheries: https://www.fisheries.noaa.gov/species/pacific-herring
  • Puget Sound Museum of Natural History: https://www.pugetsound.edu/puget-sound-museum-natural-history/exhibits/marine-panel/pacific-herring
  • USGS website: https://www.usgs.gov/labs/marrowstone-marine-field-station/science/pacific-herring-clupea-pallasii-mmfs