Pacific Herring (Clupea pallasii)
Photo: Mary Whalen, U.S. Geological Survey
Did You Know?
· When Pacific herring migrate inshore to spawn, they do not eat!
ESA Candidate Species - Southeast Alaska DPS
|Weight:||1.2 pounds (550 g)|
|Length:||up to 18 inches (46 cm)|
|Appearance:||dark blue to olive on their backs shading to silver on their sides and belly|
|Lifespan:||up to 19 years|
|Diet:|| young feed mainly on crustaceans, but also eat decapod and mollusk larvae;
adults eat mainly large crustaceans and small fishes
|Behavior:||found in large schools, studies show that Pacific herring stick together, remaining in the same school for years|
The Pacific herring is a coastal schooling species. They are found in large schools in depths from the surface to 1,300 feet (400 m). In addition to schooling, Pacific herring use countershading for protection from predators. They are dark blue to olive on their backs shading to silver on their sides and belly, making them hard to see from above and below. They can reach 18 inches (46 cm) in length and weigh up to 1.2 pounds (550 g). Herring can live up to 19 years.
Adult Pacific herring migrate inshore, entering estuaries to breed once per year, with timing varying by latitude. They do not feed from the start of this migration through spawning, a period of up to two weeks or so. The herring spawn in shallow areas along shorelines, between the subtidal and intertidal zones. Eggs are deposited on kelp, eelgrass (Zostera marina), and other available structures. After spawning, herring return to their summer feeding areas.
It is generally thought that after hatching, herring larvae remain in nearshore waters close to their spawning grounds where they feed and grow in the protective cover of shallow water habitats. After 2 to 3 months, the larvae metamorphose into juveniles. During the summer of their first year, these juveniles form schools in shallow bays, inlets and channels. These schools disappear in the fall and then move to deep water for the next 2 to 3 years.
Herring feed on phytoplankton and zooplankton in nutrient-rich waters associated with oceanic upwelling. Young feed mainly on crustaceans, but also eat decapod and mollusk larvae, whereas adults prey mainly on large crustaceans and small fishes. Although some mixing occurs, tagging studies show that Pacific herring stick together, remaining in the same school for years.
Pacific Herring Range Map
(click for larger view PDF)
Pacific Herring have numerous populations throughout the North Pacific Ocean and adjacent seas. In the western North Pacific, they are found throughout the Western Bering Sea to Kamchatka, in the Sea of Okhotsk, around Hokkaido, Japan, and south and west to the Yellow Sea. In the eastern North Pacific Ocean herring range from Baja California, Mexico, north to the Beaufort Sea, Alaska. Pacific herring are also found in the Russian Arctic from the Chukchi Sea to the White Sea.
Herring population abundance trends are very dynamic and are subject to fairly substantial changes on both large and small geographic scales. The primary cause for such fluctuations in abundance is environmental change that affects herring growth and recruitment. In Southeast Alaska, the Alaska Department of Fish and Game (ADF&G) is responsible for managing the herring fishery on a long-term, sustained yield basis. ADF&G currently monitors the Southeast Alaska Distinct Population Segment (DPS) as nine spawning aggregates including:
- Hoonah Sound
- Seymour Canal
- Tenakee Inlet
- Ernest Sound
- West Behm Canal
- Lynn Canal
The petition to list the Southeast Alaska DPS of Pacific herring under the Endangered Species Act focused on the Lynn Canal stock (see "Regulatory Overview" below). During the winters of 1972 through 1979, biomass estimates for the Lynn Canal, Alaska population (Auke Bay) exceeded 2.27 million kilograms, or approximately 2,500 tons (Carlson 1980). However, since 1981, spawning biomass estimates of the Lynn Canal Stock have been at or below 2,000 tons. From 2001 to 2004, the spawning biomass estimate was less than 1,000 tons, although recent surveys have indicated significant improvement in this stock. Because the Lynn Canal stock does not appear to be separate from other herring stocks in Southeast Alaska, the DPS was extended to include all Southeast Alaskan stocks. Population trends of all Southeast Alaskan herring stocks are currently being assessed.
- The destruction of herring spawning grounds, as well as juvenile and feeding habitat, and rearing/foraging habitat may affect herring populations. Habitat may be degraded or destroyed through decreases in water quality and by activities such as dredging, construction, log storage, and oil spills.
- Global climate change threatens to reduce the amount of phytoplankton and zooplankton prey available to Pacific herring.
- Recovering populations of predators, such as humpback whales or Steller sea lions, may impact herring consumption, further affecting populations.
- Fishing exploitation of Pacific herring in Southeast Alaska began during the late 19th century in the form of reduction fisheries. These essentially unregulated removals significantly reduced populations throughout the region until the industry closed in the 1960s. Current fisheries are managed with a goal of sustainability by ADF&G and include methods that target both adult fish and roe
The ADF&G Herring Management Plan for the eight other spawning aggregates that comprise the Southeast Alaska DPS, requires that biomass estimate meet a designated minimum threshold, preset for each of the stocks, before commercial fishing is allowed to commence. Harvest policies are then guided by a maximum exploitation rate of 20% of the exploitable or mature biomass, which is consistent with other herring fisheries on the west coast of North America. By formal policy, the exploitation rate is considered variable, increasing or decreasing as a function of biomass estimate.
On April 2, 2007, the Juneau group of the Sierra Club submitted a petition to list Pacific herring in the Lynn Canal, Alaska, area as a threatened or endangered "Distinct Population Segment" (DPS) under the criteria of the Endangered Species Act. On April 11, 2008, that petition was denied because the Lynn Canal population was not found to qualify as a DPS. However, the same Federal Register notice (73 FR 19824) announced that NMFS would be initiating a status review for a wider Southeast Alaska DPS of Pacific herring that includes the Lynn Canal population. The Southeast Alaska DPS of Pacific herring extends from Dixon Entrance northward to Cape Fairweather and Icy Point and includes all Pacific herring stocks in Southeast Alaska.
|Initiation of Status Review||73 FR 19824||04/11/2008|
- NMFS Alaska Fisheries Science Center Habitat Assessment Pacific Herring & Oil
- Alaska Department of Fish & Game (ADFG) Pacific Herring Species Profile
Updated: August 8, 2012