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Alosa sapidissima (Wilson, 1811)
American Shad
Family: Clupeidae
Introduction to the Fish

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Map


Distribution of Alosa sapidissima in British Columbia.
Source: Distribution map provided by Don McPhail for E-Fauna BC

Species Information

Dorsal spines (total): 0; Dorsal soft rays (total): 15 - 19; Anal spines: 0; Anal soft rays: 18 - 24; Vertebrae: 51 - 60. Moderately compressed, belly with a distinct keel. Lower jaw not rising steeply within mouth. Gill rakers long and slender (fewer in young). Silvery in color with blue or blue-green metallic luster on back (Ref. 1998). A dark spot on shoulder, sometimes followed by several more, or even a second row. Resembles A. pseudoharengus with lower jaw rising steeply within mouth, eyes larger, and fewer lower gill rakers, as also A. aestivalis and A. mediocris (Ref. 188). Silvery, with a green or bluish back (Ref. 7251). Branchiostegal rays 7 (Ref. 4639).

Source: FishBase. Whitehead, P.J.P. 1985 FAO species catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeioidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings. Part 1 - Chirocentridae, Clupeidae and Pristigasteridae. FAO Fish. Synop. 125(7/1):1-303.

Biology

Species Biology

Spend most of its life at sea, returning to freshwater streams to breed (Ref. 27547). Non-spawning adults are found in schools near the surface of continental shelf waters in spring, summer and fall (Ref. 7135); also found in brackish waters (Ref. 4607). Newly hatched larvae are found in rivers during the summer; by autumn they enter the sea and remain there until maturity. Juveniles form schools at 20-30 mm TL and gradually move downstream (Ref. 4639). Feed on plankton, mainly copepods and mysids, occasionally on small fishes. Feeding ceases during upstream spawning migration and resumes during the downstream post-spawning migration (Ref. 1998). Commercially caught in rivers and estuaries during spawning migration (Ref. 1998). Utilized fresh, salted, or smoked. The roe is esteemed. Eaten pan-fried, broiled, and baked (Ref. 9988). Possibly to 375 m depth (Ref. 6793). Parasites found are nematodes, Acanthocephala, copepods and distomes (Ref. 37032).

Source: FishBase. Whitehead, P.J.P. 1985 FAO species catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeioidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings. Part 1 - Chirocentridae, Clupeidae and Pristigasteridae. FAO Fish. Synop. 125(7/1):1-303.

Distribution

BC Distribution and Notes

This eastern North American species is anadromous (it breeds in fresh water but lives most of its life in the sea). It was introduced into San Francisco Bay in the late 1800s and spread rapidly in the North Pacific. Although shad occasionally enter the Fraser River (as far upstream as Hope), they have never become established in B.C.. They are not necessarily a warm-water species, they do better at warmer temperatures than salmonines. Consequently, if shad do establish themselves in the Fraser River, it may signal that something is seriously wrong with the river. Their history in the Columbia system suggests that once they become established, they can adapt to new conditions and become very numerous over an relatively short time (about 50 years). What millions of new planktivores would do to the ecological balance in the Strait of Georgia is hard to predict, but it probably would not be good.

Source: Information provided by Don McPhail for E-Fauna BC.
Global Distribution

North America: Newfoundland (Ref. 1998), the St. Lawrence River, and Nova Scotia southward to central Florida. Due to introductions into the Sacramento and Columbia Rivers, this species is now found from Cook Inlet, Alaska (Ref. 1998) to Baja California in Mexico and the Kamchatka Peninsula.

Source: FishBase. Whitehead, P.J.P. 1985 FAO species catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeioidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings. Part 1 - Chirocentridae, Clupeidae and Pristigasteridae. FAO Fish. Synop. 125(7/1):1-303.
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Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
ExoticSNAExoticNot Listed



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